user`s guide – High Frequency Structure Simulator

user`s guide – High Frequency Structure Simulator
Ansoft
HFSS
High Frequency Structure Simulator
10
electronic design automation software
user’s guide – High Frequency Structure Simulator
ANSOFT CORPORATION • 225 West Station Square Dr. Suite 200 • Pittsburgh, PA 15219-1119
The information contained in this document is subject to change without notice.
Ansoft makes no warranty of any kind with regard to this material, including,
but not limited to, the implied warranties of merchantability and fitness for a
particular purpose. Ansoft shall not be liable for errors contained herein or for
incidental or consequential damages in connection with the furnishing, performance,
or use of this material.
© 2005 Ansoft Corporation. All rights reserved.
Ansoft Corporation
225 West Station Square Drive
Suite 200
Pittsburgh, PA 15219
USA
Phone: 412-261-3200
Fax: 412-471-9427
HFSS and Optimetrics are registered trademarks or trademarks of Ansoft Corporation.
All other trademarks are the property of their respective owners.
New editions of this manual will incorporate all material updated since the previous
edition. The manual printing date, which indicates the manual’s current
edition, changes when a new edition is printed. Minor corrections and updates
which are incorporated at reprint do not cause the date to change.
Update packages may be issued between editions and contain additional and/or
replacement pages to be merged into the manual by the user. Note that pages
which are rearranged due to changes on a previous page are not considered to
be revised.
Edition: REV1.0
Date: 21 June 2005
Software Version: 10.0
Ansoft High Frequency Structure Simulator v10 User’s Guide
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Contents
Contents
This document discusses some basic concepts and terminology used throughout
the Ansoft HFSS application. It provides an overview of the following topics:
0. Fundamentals
Ansoft HFSS Desktop
Opening a Design
Setting Model Type
1. Parametric Model Creation
1.1 Boundary Conditions
1.2 Excitations
2. Analysis Setup
3. Data Reporting
4. Solve Loop
4.1 Mesh Operations
5. Examples – Antenna
6. Examples – Microwave
7. Examples – Filters
8. Examples – Signal Integrity
9. Examples – EMC/EMI
10. Examples – On Chip Components
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Ansoft HFSS Fundamentals
What is HFSS?
HFSS is a high-performance full-wave electromagnetic(EM) field simulator for
arbitrary 3D volumetric passive device modeling that takes advantage of the
familiar Microsoft Windows graphical user interface. It integrates simulation,
visualization, solid modeling, and automation in an easy-to-learn environment
where solutions to your 3D EM problems are quickly and accurately obtained.
Ansoft HFSS employs the Finite Element Method(FEM), adaptive meshing, and
brilliant graphics to give you unparalleled performance and insight to all of your
3D EM problems. Ansoft HFSS can be used to calculate parameters such as SParameters, Resonant Frequency, and Fields. Typical uses include:
Package Modeling – BGA, QFP, Flip-Chip
PCB Board Modeling – Power/Ground planes, Mesh Grid Grounds,
Backplanes
Silicon/GaAs - Spiral Inductors, Transformers
EMC/EMI – Shield Enclosures, Coupling, Near- or Far-Field Radiation
Antennas/Mobile Communications – Patches, Dipoles, Horns, Conformal
Cell Phone Antennas, Quadrafilar Helix, Specific Absorption Rate(SAR),
Infinite Arrays, Radar Cross Section(RCS), Frequency Selective
Surfaces(FSS)
Connectors – Coax, SFP/XFP, Backplane, Transitions
Waveguide – Filters, Resonators, Transitions, Couplers
Filters – Cavity Filters, Microstrip, Dielectric
HFSS is an interactive simulation system whose basic mesh element is a
tetrahedron. This allows you to solve any arbitrary 3D geometry, especially those
with complex curves and shapes, in a fraction of the time it would take using
other techniques.
The name HFSS stands for High Frequency Structure Simulator. Ansoft
pioneered the use of the Finite Element Method(FEM) for EM simulation by
developing/implementing technologies such as tangential vector finite elements,
adaptive meshing, and Adaptive Lanczos-Pade Sweep(ALPS). Today, HFSS
continues to lead the industry with innovations such as Modes-to-Nodes and FullWave Spice™.
Ansoft HFSS has evolved over a period of years with input from many users and
industries. In industry, Ansoft HFSS is the tool of choice for high-productivity
research, development, and virtual prototyping.
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Installing the Ansoft HFSS Software
System Requirements
Microsoft Windows XP(32/64), Windows 2000, or Windows 2003 Server. For upto-date information, refer to the HFSS Release Notes.
Pentium –based computer
128MB RAM minimum
8MB Video Card minimum
Mouse or other pointing device
CD-ROM drive
NOTE:
NOTE You should make backup copies of all HFSS projects created with a
previous version of the software before opening them in HFSS v10
Installing the Ansoft HFSS Software
For up-to-date information, refer to the HFSS Installation Guide
Starting Ansoft HFSS
1.
2.
Click the Microsoft Start button, select Programs,
Programs and select the Ansoft, HFSS 10
program group. Click HFSS 10.
10
Or Double click on the HFSS 10 icon on the Windows Desktop
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Converting Older Files
Converting Older HFSS file to HFSS v10
Because of changes to the HFSS files with the development of HFSS v10,
opening a HFSS document from an earlier release may take more time than you
are used to experiencing. However, once the file has been opened and saved,
subsequent opening time will return to normal
Ansoft HFSS v10 provides a way for you to automatically convert your HFSS
projects from an earlier version to the HFSS v10 format.
To access HFSS projects in an earlier version.
From HFSS v10,
v10
1. Select the menu item File > Open
2. Open dialog
1. Files of Type: Ansoft Legacy EM Projects (.cls
(.cls)
cls)
2. Browse to the existing project and select the .cls file
3. Click the Open button
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Getting Help
Getting Help
If you have any questions while you are using Ansoft HFSS you can find answers
in several ways:
Ansoft HFSS Online Help provides assistance while you are working.
To get help about a specific, active dialog box, click the Help button
in the dialog box or press the F1 key.
Select the menu item Help > Contents to access the online help
system.
Tooltips
Tooltip are available to provide information about tools on the
toolbars or dialog boxes. When you hold the pointer over a tool for a
brief time, a tooltip appears to display the name of the tool.
As you move the pointer over a tool or click a menu item, the Status
Bar at the bottom of the Ansoft HFSS window provides a brief
description of the function of the tool or menu item.
The Ansoft HFSS Getting Started guide provides detailed
information about using HFSS to create and solve 3D EM projects.
Ansoft Technical Support
To contact Ansoft technical support staff in your geographical area,
please log on to the Ansoft corporate website, www.ansoft.com and
select Contact.
Contact
Your Ansoft sales engineer may also be contacted in order to
obtain this information.
Visiting the Ansoft Web Site
If your computer is connected to the Internet, you can visit the Ansoft Web site to
learn more about the Ansoft company and products.
From the Ansoft Desktop
Select the menu item Help > Ansoft Corporate Website to access
the Online Technical Support (OTS) system.
From your Internet browser
Visit www.ansoft.com
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Getting Help
For Technical Support
The following link will direct you to the Ansoft Support Page. The Ansoft Support
Pages provide additional documentation, training, and application notes.
Web Site: http://www.ansoft.com/support.cfm
Technical Support:
9-4 EST:
Pittsburgh, PA
(412) 261-3200 x0 – Ask for Technical Support
Burlington, MA
(781) 229-8900 x0 – Ask for Technical Support
9-4 PST:
San Jose, CA
(408) 261-9095 x0 – Ask for Technical Support
Portland, OR
(503) 906-7944 or (503) 906-7947
El Segundo, CA
(310) 426-2287 – Ask for Technical Support
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WebUpdate
WebUpdate
This new feature allows you to update any existing Ansoft software from the
WebUpdate window. This feature automatically scans your system to find any
Ansoft software, and then allows you to download any updates if they are
available.
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Ansoft Terms
Ansoft Terms
The Ansoft HFSS window has several optional panels:
A Project Manager which contains a design tree which lists the structure of
the project.
A Message Manager that allows you to view any errors or warnings that
occur before you begin a simulation.
A Property Window that displays and allows you to change model
parameters or attributes.
A Progress Window that displays solution progress.
A 3D Modeler Window which contains the model and model tree for the
active design. For more information about the3D Modeler Window, see
chapter 1.
Menu
bar
Toolbars
3D Modeler
Window
Project
Manager
with project
tree
Progress
Window
Message
Manager
Status
bar
Coordinate Entry Fields
Ansoft High Frequency Structure Simulator v10 User’s Guide
Property Window
9
Ansoft Terms
Project Manager
Project Manager Window
Project
Design
Design Setup
Design Automation
•Parametric
•Optimization
•Sensitivity
•Statistical
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Design Results
10
Ansoft Terms
Property Window
Property Window
Property
buttons
Property
table
Property tabs
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Ansoft Terms
Ansoft 3D Modeler
3D Modeler Window
Graphics
area
Model
3D Modeler
design tree
Context menu
Edge
Vertex
Coordinate System (CS)
Plane
Origin
Face
Model
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Ansoft Terms
3D Modeler Design Tree
Material
Object
Object Command History
Grouped by Material
Object View
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Design Windows
Design Windows
In the Ansoft HFSS Desktop, each project can have multiple designs and each
design is displayed in a separate window.
You can have multiple projects and design windows open at the same time.
Also, you can have multiple views of the same design visible at the same time.
To arrange the windows, you can drag them by the title bar, and resize them by
dragging a corner or border. Also, you can select one of the following menu
options: Window >Cascade, Window >Tile Vertically, or Window > Tile
Horizontally.
To organize your Ansoft HFSS window, you can iconize open designs. Click the
Iconize ** symbol in the upper right corner of the document border. An icon
appears in the lower part of the Ansoft HFSS window. If the icon is not visible, it
may be behind another open document. Resize any open documents as
necessary. Select the menu item Window > Arrange Icons to arrange them at
the bottom of the Ansoft HFSS window.
Select the menu item Window > Close All to close all open design. You are
prompted to Save unsaved designs.
Iconize
Symbol
Design icons
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Toolbars
Toolbars
The toolbar buttons are shortcuts for frequently used commands. Most of the
available toolbars are displayed in this illustration of the Ansoft HFSS initial
screen, but your Ansoft HFSS window probably will not be arranged this way.
You can customize your toolbar display in a way that is convenient for you.
Some toolbars are always displayed; other toolbars display automatically when
you select a document of the related type. For example, when you select a 2D
report from the project tree, the 2D report toolbar displays.
To display or hide individual toolbars:
Right-click the Ansoft HFSS window frame.
A list of all the toolbars is displayed. The toolbars with a check mark
beside them are visible; the toolbars without a check mark are hidden.
Click the toolbar name to turn its display on or off
To make changes to the toolbars, select the menu item Tools > Customize. See
Customize and Arrange Toolbars on the
Ansoft HFSS
next page.
panels
Toolbars
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Toolbars
Customize and Arrange Toolbars
To customize toolbars:
Select the menu item Tools > Customize, or right-click the Ansoft HFSS
window frame and click Customize at the bottom of the toolbar list.
In the Customize dialog, you can do the following:
View a Description of the toolbar commands
1. Select an item from the Component pull-down list
2. Select an item from the Category list
3. Using the mouse click on the Buttons to display the
Description
4. Click the Close button when you are finished
Toggle the visibility of toolbars
1. From the Toolbar list, toggle the check boxes to control the
visibility of the toolbars
2. Click the Close button when you are finished
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Overview
Ansoft HFSS Desktop
The Ansoft HFSS Desktop provides an intuitive, easy-to-use interface for
developing passive RF device models. Creating designs, involves the following:
1. Parametric Model Generation – creating the geometry, boundaries and
excitations
2. Analysis Setup – defining solution setup and frequency sweeps
3. Results – creating 2D reports and field plots
4. Solve Loop - the solution process is fully automated
To understand how these processes co-exist, examine the illustration shown
below.
Design
Solution Type
1.1. Boundaries
1. Parametric Model
Geometry/Materials
1.2. Excitations
4.1 Mesh
Operations
2. Analysis
Solution Setup
Frequency Sweep
Mesh
Refinement
Analyze
Solve
3. Results
2D Reports
Fields
NO
Converged
4. Solve Loop
YES
Update
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Finished
17
Opening a Design
Opening a HFSS project
This section describes how to open a new or existing project.
Opening a New project
To open a new project:
1. In an Ansoft HFSS window, select the menu item File > New.
2. Select the menu Project > Insert HFSS Design.
Opening an Existing HFSS project
To open an existing project:
1. In an Ansoft HFSS window,
select the menu File > Open.
Use the Open dialog to select
the project.
2. Click Open to open the project
Opening an Existing Project from Explorer
You can open a project directly from the Microsoft Windows Explorer.
To open a project from Windows Explorer, do one of the following:
following:
Double-click on the name of the project in Windows Explorer.
Right-click the name of the project in Windows Explorer and select
Open from the shortcut menu.
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Set Solution Type
Set Solution Type
This section describes how to set the Solution Type. The Solution Type defines
the type of results, how the excitations are defined, and the convergence. The
following Solution Types are available:
1. Driven Modal - calculates the modal-based S-parameters. The S-matrix
solutions will be expressed in terms of the incident and reflected powers of
waveguide modes.
2. Driven Terminal - calculates the terminal-based S-parameters of multiconductor transmission line ports. The S-matrix solutions will be expressed
in terms of terminal voltages and currents.
3. Eignemode – calculate the eigenmodes, or resonances, of a structure. The
Eigenmode solver finds the resonant frequencies of the structure and the
fields at those resonant frequencies.
Convergence
Driven Modal – Delta S for modal S-Parameters. This was the only
convergence method available for Driven Solutions in previous versions.
Driven Terminal – Delta S for the single-ended or differential nodal SParameters.
Eigenmode - Delta F
To set the solution type:
1. Select the menu item HFSS > Solution Type
2. Solution Type Window:
1. Choose one of the following:
1. Driven Modal
2. Driven Terminal
3. Eigenmode
2. Click the OK button
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1
Parametric Model Creation
Parametric Model Creation
The Ansoft HFSS 3D Modeler is designed for ease of use and flexibility. The
power of the 3D Modeler is in its unique ability to create fully parametric designs
without editing complex macros/model history.
The purpose of this chapter is to provide an overview of the 3D Modeling
capabilities. By understanding the basic concepts outlined here you will be able
to quickly take advantage of the full feature set offered by the 3D Parametric
Modeler.
Overview of the 3D Modeler User Interface
The following picture shows the 3D Modeler window.
3D Modeler Design Tree – The 3D Modeler Design Tree is an essential part
of the user interface. From here you may access the structural elements in
addition to any object dependencies and attributes.
Context Menus – Context menus are a flexible way of accessing frequently
used menu commands for the current context. The contents of these
menus change dynamically and are available throughout the interface by
clicking the right mouse button.
Graphics Area – The graphics area is used to interact with the structural
elements.
Graphics
area
Model
3D Modeler
design tree
Context menu
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Parametric Model Creation
Overview of the 3D Modeler User Interface (Continued)
When using the 3D Modeler interface you will also interact with two additional
interfaces:
Property Window – The Property Window is used to view or modify the
attributes and dimensions of structural objects
Property
buttons
Property
table
Property tabs
Status Bar/Coordinate Entry – The Status Bar on the Ansoft HFSS Desktop
Window displays the Coordinate Entry fields that can be used to define
points or offsets during the creation of structural objects
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Parametric Model Creation
Grid Plane
To simplify the creation of structural primitives, a grid or drawing plane is used.
The drawing plane does not in any way limit the user to two dimensional
coordinates but instead is used as a guide to simplify the creation of structural
primitives. The drawing plane is represented by the active grid plane (The grid
does not have to be visible). To demonstrate how drawing planes are used,
review the following section: Creating and Viewing Simple Structures.
Structures
Active Cursor
The active cursor refers to the cursor that is available during object creation. The
cursor allows you to graphically change the current position. The position is
displayed on the status bar of the Ansoft HFSS Desktop Window.
When objects are not being constructed, the cursor remains passive and is set
for dynamic selection. See the Overview of Selecting Objects for more details.
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Parametric Model Creation
Creating and Viewing a Simple Structure
Creating 3D structural objects is accomplished by performing the following steps:
1. Set the grid plane
2. Create the base shape of the object
3. Set the Height
Create a Box
We will investigate creating a box to demonstrate these steps. These steps
assume that project and a HFSS design have already been created. Three
points are required to create the box. The first two form the base rectangle
and the third sets the height.
Point 1: Defines the start point of the base rectangle
Point 2: Defines the size of the base rectangle
Point 3: Defines the height of the Box
Point 1
Grid Plane
Point 3
Base Rectangle
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Point 2
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Parametric Model Creation
Create a Box (Continued)
1. Select the menu item 3D Modeler > Grid Plane > XY
2. Use the mouse to create the base shape
1. Set the start point by positioning the active cursor and click the left
mouse button.
2.
3.
Position the active cursor and click the left mouse button to set the
second point that forms the base rectangle
Set the Height by positioning the active cursor and clicking left mouse
button.
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Parametric Model Creation
Specifying Points
Grid
From the example, we saw that the simplest way to set a point is by
clicking its position on the grid plane. To set the precision of the grid plane,
select the menu item View > Grid Settings. From here you may specify the
Grid Type, Style, Visibility, and Precision. By pressing the Save As Default
button, you can set the default behavior for future HFSS Designs.
Coordinate Entry
Another way to specify a coordinate is to use the Coordinate Entry fields
which are located on the status bar of the Ansoft HFSS Desktop. The
position may be specified in Cartesian, Cylindrical,
Cylindrical or Spherical
coordinates. Once the first point is set, the Coordinate Entry will default to
Relative coordinates. In Relative mode the coordinates are no longer
absolute (measured from the origin of the working coordinate system), but
relative to the last point entered.
Equations
The Coordinate Entry fields allow equations to be entered for
position values. Examples: 2*5, 2+6+8, 2*cos(10*(pi/180)).
Variables are not allowed in the Coordinate Entry Field
Note:
Note Trig functions are in radians
Relative mode
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Parametric Model Creation
Specifying Points (Continued)
Object Properties
By default the Properties dialog will appear after you have finished
sketching an object. The position and size of objects can be modified from
the dialog. This method allows you to create objects by clicking the
estimated values using the mouse and then correcting the values in the
final dialog.
The Property dialog accepts equations, variables, and units. See the
Overview of Entering Parameters for more detail.
Every object has two types of properties
1. Command – Defines the structural primitive
2. Attributes – Defines the material, display, and solve properties
Commands
Attributes
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Parametric Model Creation
Overview of Draw
Primitives
In solid modeling, the basic element or object is often called a primitive.
Examples of primitives are boxes, cylinders, rectangles, circles, etc. There
are two types of primitives: 3D primitives or solids, and 2D primitives or
surfaces. By placing a collection of primitives in the correct location and of
the correct size we can create a represent complex structural objects.
To create complex objects, primitives can be used as “tools” to cut holes,
carve away, or join. The operations that are performed with these “tools”
are often referred to as Boolean operations.
2D primitives can be swept to create arbitrarily shaped solid primitives
2D Draw Objects
The following 2D Draw objects are available:
Rectangle, Circle, Line, Point, Spline, Ellipse, Regular Polygon (v8.5
circle)
3D Draw Objects
The following 3D Draw objects are available:
Box, Cylinder, Sphere, Torus, Helix, Bond Wire, Cone, Regular
Polyhedron (v8.5 cylinder)
True Surfaces
Circles, Cylinders, Spheres, etc are represented as true surfaces. In
versions prior to release 9, these primitives would be represented as
faceted objects. If you wish to use the faceted primitives (Cylinders or
Circles), select the Regular Polyhedron or Regular Polygon.
To control the mesh generation of true surfaces objects, see the section on
Mesh Control.
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Parametric Model Creation
Overview of Draw (Continued)
Snap Mode
As an aid for graphical selection, the
modeler provides Snap options. The
default is to snaps are shown here. The
shape of the active cursor will dynamically
change as the cursor is moved over the
snap positions.
Moving
By default all active cursor movement is in three dimensions. The modeler
can also be set to allow the active cursor to only move in a plane or out of
plane. These are set from the menu item 3D Modeler > Movement Mode.
In addition, the movement can be limited to a specific direction (x, y, or z)
by holding down the x, y, or z key. This prevents movement in the other
directions.
Pressing the CTRL+Enter key sets a local reference point. This can be
useful for creating geometry graphically that is based on an existing
objects. This is outlined on the next page:
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Parametric Model Creation
Moving (Continued)
Step 1: Start Point
Step 3: CTRL+Enter Keys set a local reference
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Step 2: Hold X key and select vertex point
Step 4: Hold Z key and set height
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Parametric Model Creation
Overview of Draw
Import
In 3D modeler you can import a drawing file from outside.
Choose option 3D Modeler -> Import . Here is the list of import files that we
support. For some of these import option you will need an add-on translator
feature in your license file.
Healing
Automated healing for imported solid models
Post-translation user controlled healing
3D Model Analysis – 3D Modeler/Analyze
Face, Object , Area analysis based on user inputs
List of problems (faces, edges, vertices)
Auto Zoom In into region where problem exists
Remove Face
Remove Edge
Remove Sliver
Remove Vertices
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Parametric Model Creation
Selecting Previously Defined Shapes
You may select an object by moving the mouse over the object in the graphics
area and clicking on it. The default mode is Dynamic selection which will display
the object to be selected with a unique outline color. Please note that after
selecting (Clicking on the object) the object it will be displayed solid pink while all
other objects are drawn transparent.
Types of Selection
The default is to select objects. Sometimes is necessary to select faces,
edges, or vertices. To change the selection mode, select the menu item
Edit > Select and choose the appropriate selection mode. The shortcut
keys o (Object selection) and f (face selection) are useful for quickly
switching between the most common selection modes
Multiple Select or Toggle Selection
Multiple objects can be selected graphically by holding down the CTRL key
while selecting. In addition, with the CTRL key pressed, the selection of an
object can be toggled between selected or unselected.
Blocked Objects
If the object you wish to select is located behind another object, select the
object that is blocking the desired object and press the b key or right-click
and select Next Behind from the context menu. You may repeat this as
many times as needed to select the correct object.
Select All Visible
You can select all visible objects by pressing the CTRL+a key or by
selecting the menu item Edit > Select All Visible.
Select by Name
To select objects by Name you can use anyone of the following:
Select the menu item Edit > Select > By Name
Select the menu item HFSS > List
Select the Model tab
Select objects from the list
Use the Model Tree. See the next page
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Parametric Model Creation
Selecting Previously Defined Shapes (Continued)
Model Tree
After an object has been created, it is automatically added to the Model
Tree. All objects can be found in the Model Tree. If you open the Model
folder you will find the objects sorted by Object or by Material. You can
toggle between the views by toggling the menu item 3D Modeler > Group
Object by Material.
Sorted by Object
Sorted by Material
As stated previously, every object has two types of properties:
Attributes
You may select an object by clicking on the corresponding
item in the Model Tree.
When the object is selected the attributes will be displayed in
the Property Window. Double-clicking on the object will open
a properties dialog. Use the Property Window or properties
dialog to modify the attributes.
Commands
From the Model Tree, the Command Properties can be
selected by expanding the object folder to display the
command list. Using the mouse, select the corresponding
Attributes
command from the tree. The properties will be displayed in
Commands
the Property Window. Double-clicking on the command will
open a properties dialog. Use the Property Window or
properties dialog to modify the command.
When the command is selected, the object will be outlined
with bold lines in the 3D Model Window. Since an object can
be a combination of several primitives, the command list may
contain several objects. Anyone of these commands can be
selected to visualize or modify the object.
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Parametric Model Creation
Selecting Previously Defined Shapes (Continued)
Model Tree
Geometry in the 3D modeler is also grouped according to their model
definition. Objects, Sheets, Lines, and Points are all separated so that they
can be easily identified in the model tree
If a boundary condition or an excitation is defined on a sheet object, then
those 2D objects will be further separated according to their assignment.
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Parametric Model Creation
Object Attributes
An objects attributes set the following user defined properties:
Name – User defined name. Default names start with the primitive type
followed by an increasing number: Box1, Box2, etc.
Material – User defined material property. The default property is vacuum.
This can be changed by using the material toolbar
Solve Inside – By default HFSS only solves for fields inside
dielectrics. To force HFSS to solve inside conductors, check
solve inside.
Orientation
Model Object – Controls if the object is included in the solve
Display Wireframe – Forces the object to always be displayed as wireframe
Color – Set object color
Transparency – Set the transparency of an object. 0–Solid, 1- Wireframe
Note: Visibility is not an object property.
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Parametric Model Creation
Materials
By clicking on the property button for the material name, the material definition
window will appear. You can select from the existing database or define a
custom project material.
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Parametric Model Creation
Materials (Continued)
User Defined Project Material
To define a custom material click the Add Material button from the material
definition window. The following dialog will appear. Enter the material
definitions and click the OK button.
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Parametric Model Creation
Changing the View
You can change the view at any time (even during shape generation) by using
the following commands:
Toolbar
Rotate – The structure will be rotated around the coordinate system
Pan – The structure will be translated in the graphical area
Dynamic Zoom – Moving the mouse upwards will increase the zoom factor
while moving the mouse downwards will decrease the zoom factor
Zoom In/Out – In this mode a rubber band rectangle will be defined by
dragging the mouse. After releasing the mouse button the zoom factor will
be applied.
Pan
Zoom In/Out
Rotate
Dynamic Zoom
Context Menu
Right click in the graphics area and select the menu item View and choose
from the options outlined in the Toolbar section. The context menu also
offers the following:
Fit All – This will zoom the defined structure to a point where it fits in
the drawing area
Fit Selection – This fits only the selected objects into the drawing
area.
Spin – Drag the mouse and release the mouse button to start the
object spinning. The speed of the dragging prior to releasing the
mouse controls the speed of the spin.
Animate – Create or display the animation of parametric geometry
Shortcuts
Since changing the view is a frequently used operation, some useful
shortcut keys exist. Press the appropriate keys and drag the mouse with
the left button pressed:
ALT + Drag – Rotate
In addition, there are 9 pre-defined view angles that can be
selected by holding the ALT key and double clicking on the
locations shown on the next page.
Shift + Drag - Pan
ALT + Shift + Drag – Dynamic Zoom
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Parametric Model Creation
Shortcuts - Predefined Views
These 9 pre-defined views can be seen by holding the ALT key and double
clicking the left mouse button on the locations shown below.
Top
Predefined View Angles
Right
Left
Bottom
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Parametric Model Creation
Changing the View (Continued)
Visibility
The visibility of objects, Boundaries, Excitations, and Field Reports can be
controlled from the menu item View > Visibility
Hide Selection
The visibility of selected objects can be set hidden by selecting the
object(s) and choosing the menu View > Hide Selection > All Views.
Rendering
To change the rendering select the menu item View > Render > Wireframe
or View > Render > Smooth Shaded
Coordinate System
To control the view of the coordinate system, select the menu item:
Visibility:
Toggle the menu item View > Coordinate System > Hide
(Show)
Size:
Size
Toggle the menu item View > Coordinate System > Small
(Large)
Background Color
To set the background color, select the menu item View > Modify Attributes
> Background Color
Addition View Seetings
Additional attributes of the view such as the projection, orientation, and
lighting can be set from the menu item View > Modify Attributes
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Parametric Model Creation
Enhancements and New Features
Selection
Select Connected Vertices
Select Connected Faces
Select Connected Edges
Select Edge Chain
Select Face Chain
Select Uncovered Loops
Healing
Purge History – makes an object appear as an
imported entity so that healing can be
performed on it
Remove Faces
Remove Edges
Remove Vertices
Align Faces
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Parametric Model Creation
Enhancements and New Features
Visibility
Hide selected objects in Active View
Hide selected objects in All Views
Show selected objects in Active View
Show selected objects in All Views
3D User Interface Options
When there is a selection
Selection is always visible
Set transparency of selected objects
Set transparency of non-selected objects
Default Rotation About
Screen Center
Current Axis
Model Center
3D Modeler Options
Visualize history of objects
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Parametric Model Creation
Applying Structural Transformations
So far we have investigated hot to model simple shapes and how to change the
view of the model. To create more complicated models or reduce the number of
objects that need to be created manually we can apply various transformations.
The following examples assume that you have already selected the object(s) that
you wish to apply a transformation.
You can select the transformation options from the menu item Edit >
Arrange >
Move – Translates the structure along a vector
Rotate – Rotates the shape around a coordinate axis by an angle
Mirror – Mirrors the shape around a specified plane
Offset – Performs a uniform scale in x, y, and z.
Duplicate >
Along Lines – Create multiple copies of an object along a vector
Around Axis – Create multiple copies of an object rotated by a fixed
angle around the x, y, or z axis
Mirror - Mirrors the shape around a specified plane and creates a
duplicate
Scale – Allows non-uniform scaling in the x, y, or z direction
The faces of an object can also be moved to alter the shape of an existing object.
To move the faces of an object select the menu item 3D Modeler > Surfaces >
Move Faces and select Along Normal or Along Vector.
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Parametric Model Creation
Combine Objects by Using Boolean Operations
Most complex structures can be reduced to combinations of simple primitives.
Even the solid primitives can be reduced to simple 2D primitives that are swept
along a vector or around an axis(Box is a square that is swept along a vector to
give it thickness). The solid modeler supports the following Boolean operations:
Unite – combine multiple primitives
Unite disjoint objects
Separate Bodies to separate
Subtract – remove part of a primitive from another
Split – break primitives into multiple parts
Intersect–
Intersect keep only the parts of primitives that overlap
Sweep – turn a 2D primitive into a solid by sweeping: Along a Vector,
Around an Axis, Along a Path
Connect – connect 2D primitives. Use Cover Surfaces to turn the
connected object into a solid
Section – generate 2D cross-sections of a 3D object
Most Boolean operations require a base primitive in which the Boolean operation
is performed. Only the base object will be preserved.
The Boolean functions provide the option to Clone objects.
Split Crossing Objects – When a group of objects
are selected, a Boolean split is performed on
ANY objects that overlap
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Parametric Model Creation
Local Coordinate Systems
The ability to create local coordinate systems adds a great deal of flexibility to the
creations of structural objects. In previous sections we have only discussed
objects that are aligned to the global coordinate system. The local coordinate
system simplifies the definition of objects that do not align with the global
coordinate system. In addition, the object history is defined relative to a
coordinate system. If the coordinate system is moved, the geometry will
automatically move with it. The definition of coordinate systems are maintained
in the Model Tree.
Working Coordinate System
The working coordinate system is the currently selected CS. This can be a
local or global CS
Global CS
The default fixed coordinate system
Relative CS
User defined local coordinate system.
Offset
Rotated
Both
Face CS
User defined local coordinate system. It is tied to the location of the object
face it was created on. If the size of the base object changes, all objects
created relative to the face CS will be updated automatically.
Continued on Next Page
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Parametric Model Creation
Local Coordinate Systems (Continued)
Face CS (Continued)
To create a face CS, select the menu item 3D Modeler > Coordinate
System > Face
1.
2.
3.
Graphically select Face (Highlighted in model)
Select Origin for Face CS
Set X-Axis
Step 1: Select Face
Step 3: Set X-Axis
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Step 2: Select Origin
New Working CS
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Parametric Model Creation
Local Coordinate Systems (Continued)
Example of Face CS
Cone is created with Face CS
Change the size of the box and
the Cone is automatically
moved with the Face CS
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Parametric Model Creation
Parametric Geometry
The parametric modeler capability allows us to define variables in replace of a
fixed position or size. Once this has been defined the variable can be changed
by the user or by Optimetrics. Optimetrics can then be used to perform
automatic Optimization, Parametric Sweeps, Statistical, or Sensitivity Analysis.
Defining Parameters
Select the command to parameterized
Choose the value to change
Enter a variable in replace of the fixed value
Define the variable using any combination of math functions or design
variables.
The model will automatically be updated
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Parametric Model Creation
Parametric Geometry (Continued)
Variables
There are two types of variables that can be defined in the HFSS Desktop
Design Properties – Local to model. To access the local variables
select the menu item HFSS > Design Properties
Project Variables – Global to all models in project. Start with $. To
access the global or project variables, select the menu item Project
> Project Variables
Units
When defining variables they must contain units. The default units
for variables is meters.
Equations
The variables can contain complex equations. See the Online Help
for a complete list of math functions
Equation based Curves and Surfaces
Any curve/surface that can be described
by an equation in three dimensions
can be drawn.
Animation
Right-Click in the 3D Model Window & Choose Animate to preview
the parameterization
Note: depending on the quality of your graphics card you have the
option of exporting ether AVI or GIF animation files.
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Boundary Conditions
Boundary Conditions
This chapter describes the basics for applying boundary conditions. Boundary
conditions enable you to control the characteristics of planes, faces, or interfaces
between objects. Boundary conditions are important to understand and are
fundamental to solution of Maxwell’s equations.
Why they are Important
The wave equation that is solved by Ansoft HFSS is derived from the differential
form of Maxwell’s Equations. For these expressions to be valid, it is assumed
that the field vectors are single-valued, bounded, and have continuous
distribution along with their derivatives. Along boundaries or sources, the fields
are discontinuous and the derivatives have no meaning. Therefore boundary
conditions define the field behavior across discontinuous boundaries.
As a user of Ansoft HFSS you should be aware of the field assumptions made by
boundary conditions. Since boundary conditions force a field behavior we want
to be aware of the assumptions so we can determine if they are appropriate for
the simulation. Improper use of boundary conditions may lead to inconsistent
results.
When used properly, boundary conditions can be successfully utilized to reduce
the model complexity. In fact, Ansoft HFSS automatically uses boundary
conditions to reduce the complexity of the model. Ansoft HFSS can be thought of
as a virtual prototyping world for passive RF devices. Unlike the real world
which is bounded by infinite space, the virtual prototyping world needs to be
made finite. In order to achieve this finite space, Ansoft HFSS applies a
background or outer boundary condition which is applied to the region
surrounding the geometric model.
The model complexity usually is directly tied to the solution time and computer
resources so it is a competitive advantage to utilize them whenever possible.
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Boundary Conditions
Common Boundary Conditions
There are three types of boundary conditions. The first two are largely the users
responsibility to define them or ensure that they are defined correctly. The
material boundary conditions are transparent to the user.
1. Excitations
Wave Ports (External)
Lumped Ports (Internal)
2. Surface Approximations
Symmetry Planes
Perfect Electric or Magnetic Surfaces
Radiation Surfaces
Background or Outer Surface
3. Material Properties
Boundary between two dielectrics
Finite Conductivity of a conductor
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Boundary Conditions
How the Background Affects a Structure
The background is the region that surrounds the geometric model and fills any
space that is not occupied by an object. Any object surface that touches the
background is automatically defined to be a Perfect E boundary and given the
boundary name outer. You can think of your structure as being encased with a
thin, perfect conductor.
If it is necessary, you can change a surface that is exposed to the background to
have properties that are different from outer:
To model losses in a surface, you can redefine the surface to be either a
Finite Conductivity or Impedance boundary. A Finite Conductivity
boundary can be a lossy metal, with loss as a function of frequency and
defined using conductivity and relative permeability parameters. An
Impedance boundary has real or complex values that by default remain
constant over frequency.
To model a surface to allow waves to radiate infinitely far into space,
redefine the surface to be radiation boundary.
The background can affect how you make material assignments. For example, if
you are modeling a simple air-filled rectangular waveguide, you can create a
single object in the shape of the waveguide and define it to have the
characteristics of air. The surface of the waveguide is automatically assumed to
be a perfect conductor and given the boundary condition outer, or you can
change it to a lossy conductor.
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Boundary Conditions
Boundary Condition Precedence
The order in which boundaries are assigned is important in HFSS. Latter
assigned boundaries take precedence over former assigned boundaries.
For example, if one face of an object is assigned to a Perfect E boundary, and a
hole which lies in the same plane as this surface is assigned a Prefect H
boundary, then the Perfect H will override the Perfect E in the area of the hole,
and the E field will pass through the hole. If this operation were performed in the
reverse order, then the Perfect E boundary would cover the Perfect H boundary,
and no field would penetrate.
Once boundaries have been assigned, they can be re-prioritized by selecting
HFSS > Boundaries > ReRe-prioritize. The order of the boundaries can be changed
by clicking on a boundary and dragging it further up or down in the list. NOTE:
Ports will always take the highest precedence.
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Boundary Conditions
Technical Definition of Boundary Conditions
Excitation – An excitation port is a type of boundary condition that permits energy
to flow into and out of a structure. See the section on Excitations.
Perfect E – Perfect E is a perfect electrical conductor, also referred to as a perfect
conductor. This type of boundary forces the electric field (E-Field) perpendicular
to the surface. There are also two automatic Perfect E assignments:
Any object surface that touches the background is automatically defined to
be a Perfect E boundary and given the boundary condition name outer.
Any object that is assigned the material pec (Perfect Electric Conductor) is
automatically assigned the boundary condition Perfect E to its surface and
given the boundary condition name smetal.
Perfect H – Perfect H is a perfect magnetic conductor. Forces E-Field tangential
to the surface.
Natural – for a Perfect H boundary that overlaps with a perfect E boundary,
this reverts the selected area to its original material, erasing the Perfect E
boundary condition. It does not affect any material assignments. It can be
used, for example, to model a cut-out in a ground plane for a coax feed.
Finite Conductivity –A Finite Conductivity boundary enables you to define the
surface of an object as a lossy (imperfect) conductor. It is an imperfect E
boundary condition, and is analogous to the lossy metal material definition. To
model a lossy surface, you provide loss in Siemens/meter and permeability
parameters. Loss is calculated as a function of frequency. It is only valid for
good conductors. Forces the tangential E-Field equal to Zs(n x Htan). The
surface impedance (Zs) is equal to, (1+j)/(δσ), where:
δ is the skin depth, (2/(ωσµ))0.5 of the conductor being modeled
ω is the frequency of the excitation wave.
σ is the conductivity of the conductor
µ is the permeability of the conductor
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Boundary Conditions
Technical Definition of Boundary Conditions (Continued)
Impedance – a resistive surface that calculates the field behavior and losses
using analytical formulas. Forces the tangential E-Field equal to Zs(n x Htan).
The surface impedance is equal to Rs + jXs, where:
Rs is the resistance in ohms/square
Xs is the reactance in ohms/square
Layered Impedance – Multiple thin layers in a structure can be modeled as an
impedance surface. See the Online Help for additional information on how to use
the Layered Impedance boundary.
Lumped RLC – a parallel combination of lumped resistor, inductor, and/or
capacitor surface. The simulation is similar to the Impedance boundary, but the
software calculate the ohms/square using the user supplied R, L, C values.
Infinite Ground Plane – Generally, the ground plane is treated as an infinite,
Perfect E, Finite Conductivity, or Impedance boundary condition. If radiation
boundaries are used in a structure, the ground plane acts as a shield for far-field
energy, preventing waves from propagating past the ground plane. to simulate
the effect of an infinite ground plane, check the Infinite ground plane box when
defining a Perfect E, Finite Conductivity, or Impedance boundary condition.
NOTE: Enabling the Infinite Ground Plane approximation ONLY affects postprocessed far-field radiation patterns. It will not change the current flowing on the
ground plane.
Radiation – Radiation boundaries, also referred to as absorbing boundaries,
enable you to model a surface as electrically open: waves can then radiate out of
the structure and toward the radiation boundary. The system absorbs the wave at
the radiation boundary, essentially ballooning the boundary infinitely far away
from the structure and into space. Radiation boundaries may also be placed
relatively close to a structure and can be arbitrarily shaped. This condition
eliminates the need for a spherical boundary. For structures that include radiation
boundaries, calculated S-parameters include the effects of radiation loss. When
a radiation boundary is included in a structure, far-field calculations are
performed as part of the simulation.
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Boundary Conditions
Technical Definition of Boundary Conditions (Continued)
Symmetry - represent perfect E or perfect H planes of symmetry. Symmetry
boundaries enable you to model only part of a structure, which reduces the size
or complexity of your design, thereby shortening the solution time. Symmetry
boundaries, as opposed to a simple Perfect E or H plane, should be used when
the plane cuts across a port. In this instance, the port has a different amount of
power, voltage, and current associated with it, and thus a different impedance. To
make a port with a symmetry plane look like a full-sized port, you must use the
Impedance Multiplier in the boundary wizard.
For a single Symmetry H boundary, the Impedance Multiplier is 0.5.
For a single Symmetry E boundary, the Impedance Multiplier is 2.
Other considerations for a Symmetry boundary condition:
A plane of symmetry must be exposed to the background.
A plane of symmetry must not cut through an object drawn in the 3D
Modeler window.
A plane of symmetry must be defined on a planar surface.
Only three orthogonal symmetry planes can be defined in a problem
Master / Slave - Master and slave boundaries enable you to model planes of
periodicity where the E-field on one surface matches the E-field on another to
within a phase difference. They force the E-field at each point on the slave
boundary match the E-field to within a phase difference at each corresponding
point on the master boundary. They are useful for simulating devices such as
infinite arrays. Some considerations for Master/Slave boundaries:
They can only be assigned to planar surfaces.
The geometry of the surface on one boundary must match the geometry
on the surface of the other boundary.
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Boundary Conditions
Arbitrary Wave Sources
Polarized plane waves (circular, elliptical)
Evanescent plane waves
Gaussian beams
Hertzian Dipole and Line Source
Linear antenna
.
glass
air
Incident Gaussian Beam
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Total Fields
1.1-8
1.1
Boundary Conditions
Frequency Selective Surfaces
Automated Reflection & Transmission computation
interpolating sweep may be applied !
.
Frequency Selective Surfaces: Theory and Design,
Design
Ben A. Munk, Fig 2.15, pg 38
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1.2
Excitations
Technical Overview
Ports are a unique type of boundary condition that allow energy to flow into and
out of a structure. You can assign a port to any 2D object or 3D object face.
Before the full three-dimensional electromagnetic field inside a structure can be
calculated, it is necessary to determine the excitation field pattern at each port.
Ansoft HFSS uses an arbitrary port solver to calculate the natural field patterns or
modes that can exist inside a transmission structure with the same cross section
as the port. The resulting 2D field patterns serve as boundary conditions for the
full three-dimensional problem.
By default Ansoft HFSS assumes that all structures are completely
encased in a conductive shield with no energy propagating through it. You
apply Wave Ports to the structure to indicate the area were the energy
enters and exits the conductive shield.
As an alternative to using Wave Ports,
Ports you can apply Lumped Ports to a
structure instead. Lumped Ports are useful for modeling internal ports
within a structure.
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Excitations
Wave Port
The port solver assumes that the Wave Port you define is connected to a semiinfinitely long waveguide that has the same cross-section and material properties
as the port. Each Wave Port is excited individually and each mode incident on a
port contains one watt of time-averaged power. Wave Ports calculate
characteristic impedance, complex propagation constant, and generalized SParameters.
Wave Equation
The field pattern of a traveling wave inside a waveguide can be determined
by solving Maxwell’s equations. The following equation that is solved by
the 2D solver is derived directly from Maxwell’s equation.
 1

∇ ×  ∇ × E ( x, y ) − k02ε r E ( x, y ) = 0
 µr

where:
E(x,y) is a phasor representing an oscillating electric field.
k0 is the free space wave number,
µr is the complex relative permeability.
εr is the complex relative permittivity.
To solve this equation, the 2D solver obtains an excitation field pattern in
the form of a phasor solution, E(x,y). These phasor solutions are
independent of z and t; only after being multiplied by e-γz do they become
traveling waves.
Also note that the excitation field pattern computed is valid only at a single
frequency. A different excitation field pattern is computed for each
frequency point of interest.
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Excitations
Modes
For a waveguide or transmission line with a given cross section, there is a series
of basic field patterns (modes) that satisfy Maxwell’s Equations at a specific
frequency. Any linear combination of these modes can exist in the waveguide.
Mode Conversion
In some cases it is necessary to include the effects of higher-order modes
because the structure acts as a mode converter. For example, if the mode
1 (dominant) field at one port is converted (as it passes through a structure)
to a mode 2 field pattern at another, then it is necessary to obtain the Sparameters for the mode 2 field.
Modes, Reflections, and Propagation
It is also possible for a 3D field solution generated by an excitation signal of
one specific mode to contain reflections of higher-order modes which arise
due to discontinuities in a high frequency structure. If these higher-order
modes are reflected back to the excitation port or transmitted onto another
port, the S-parameters associated with these modes should be calculated.
If the higher-order mode decays before reaching any port—either because
of attenuation due to losses or because it is a non-propagating evanescent
mode—there is no need to obtain the S-parameters for that mode.
Modes and Frequency
The field patterns associated with each mode generally vary with
frequency. However, the propagation constants and impedances always
vary with frequency. Therefore, when a frequency sweep has been
requested, a solution is calculated for each frequency point of interest.
When performing frequency sweeps, be aware that as the frequency
increases, the likelihood of higher-order modes propagating also increases.
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Excitations
Modes and S-Parameters
When the Wave Ports are defined correctly, for the modes that are included
in the simulation, there is a perfect matched condition at the Wave Port.
Because of this, the S-Parameters for each mode and Wave Port are
normalized to a frequency dependent impedance. This type of SParameter is referred to as Generalized S-Parameter.
Laboratory measurements, such as those from a vector network analyzer,
or circuit simulators use a constant reference impedance (i.e. the ports are
not perfectly matched at every frequency).
To obtain results consistent with measurements or for use with
circuit simulators, the generalized s-parameters calculated by Ansoft
HFSS must be renormalized to a constant characteristic impedance.
See the section on Calibrating Wave Ports for details on how to
perform the renormalization.
Note: Failure to renormalize the generalized S-Parameters may
result in inconsistent results. For example, since the Wave Ports
are perfectly matched at every frequency, the S-Parameters do not
exhibit the interaction that actually exists between ports with a
constant characteristic impedance.
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1.2
Excitations
Wave Port Boundary Condition
The edge of a Wave Port can have the following boundary conditions:
Perfect E or Finite Conductivity – by default the outer edge of a Wave Port
is defined to have a Perfect E boundary. With this assumption, the port is
defined within a waveguide. For transmission line structures that are
enclosed by metal, this is not a problem. For unbalanced or non-enclosed
lines, the fields in the surrounding dielectric must be included. Improper
sizing of the port definition will result in erroneous results.
Symmetry – the port solver understands Perfect E and Perfect H symmetry
planes. The proper Wave Port impedance multiplier needs to be applied
when using symmetry planes.
Impedance – the port solver will recognize an impedance boundary at the
edges of the ports.
Radiation – the default setting for the interface between a Wave Port and a
Radiation boundary is to apply a Perfect E boundary to the edge of the
ports.
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Excitations
Calibrating Wave Ports
Wave Ports that are added to a structure must be calibrated to ensure consistent
results. This calibration is required in order to determine direction and polarity of
fields and to make voltage calculations.
Solution Type: Driven Modal
For Driven Modal simulations, the Wave Ports are calibrated using
Integration Lines. Each Integration Line is used to calculate the following
characteristics:
Impedance – As an impedance line, the line serves as the path over
which Ansoft HFSS integrates the E-field to obtain the voltage at a
Wave Port. Ansoft HFSS uses the voltage to compute the
characteristic impedance of the Wave Ports, which is needed to
renormalize generalized S-matrices to specific impedances such as
50 ohms.
Note: If you want to be able to renormalize S-parameters or
view the values of Zpv or Zvi, you must apply Integration
Lines to the Wave Ports of a structure.
Calibration – As a calibration line, the line explicitly defines the up or
positive direction at each Wave Port. At any Wave Port, the
direction of the field at ωt = 0 can be in at least one of two directions.
At some ports, such as circular ports, there can be more than two
possible directions, and you will want to use Polarize E-Field. If you
do not define an Integration Line, the resulting S-parameters can be
out of phase with what you expect.
Tip You may need to run a ports-only solution first to help determine how
the Integration Lines need to be applied to a Wave Port and their direction.
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Excitations
To calibrate a Wave Port, that has already been defined, with an
Integration Line:
1. From the Project Tree,
Tree expand Excitations and double click on the
Wave Port to be calibrated
2. Select the Modes tab.
3. From the table, select the Integration Line column for the first mode
and choose New Line.
Line
4. Enter the position and length of the line using one of the following
methods
Type the start and stop points of the line directly into the x, y,
or z axis fields, referenced to the working coordinates. For
more information on coordinates, refer to “Getting Oriented in
the Drawing Space” in Chapter **, Drawing Basics and Tips.
Graphically pick the points in the Design Window’s graphics
area. The line is displayed as a vector; the vector indicates
direction. From the Integration Line column, select Swap
Endpoints to reverse the direction of the line, if necessary.
5. Repeat steps 3 and 4 to define and apply lines to other modes of the
current Wave Port.
6. Click the OK button when you are finished defining Integration Lines
7. Repeat steps 1-6 to apply lines to other Wave Ports.
Step 3: Create New Line
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Excitations
About Impedance Lines
The S-matrices initially calculated by Ansoft HFSS are generalized Smatrices normalized to the impedances of each port. However, it is often
desirable to compute S-matrices that are normalized to specific
impedances such as 50 ohms. To convert a generalized S-matrix to a
renormalized S-matrix, Ansoft HFSS first computes the characteristic
impedance at each port. There are several ways to compute the
characteristic impedance (Zpi, Zpv, Zvi).
Ansoft HFSS will always calculate Zpi. The impedance calculation using
power and current is well defined for a Wave Port. The other two methods
– Zpv and Zvi – require a line of integration to determine voltage. By defining
an Integration Line for each mode, the voltage can be computed.
In general, the impedance line should be defined between two points at
which the voltage differential is expected to be a maximum. If you are
analyzing multiple modes, define a separate Integration Lines for each
mode since the orientation of the electric field will vary.
About Calibration Lines
When the excitation field pattern at a Wave Port is computed, the direction
of the field at ωt=0 is arbitrary and can point in one of at least two ways.
The Integration Lines calibrate the port by defining the preferred direction
or the reference orientation. Be sure to define Integration Lines for each
Wave Port so that the preferred direction is the same relative to other ports
having identical or similar cross-sections. In this way, the results of
laboratory measurements (in which the setup is calibrated by removing the
structure and connecting two ports together) can be duplicated.
Because the calibration lines only determine the phase of the excitation
signal and the traveling wave, the system ignores them during the PortsOnly solution
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1.2
Excitations
Solution Type: Driven Terminal
The Modal S-matrix solution computed by Ansoft HFSS is expressed in
terms of the incident and reflected powers of the waveguide modes. This
description does not lend itself to problems where several different quasitransverse electromagnetic (TEM) modes can propagate simultaneously.
For structures like coupled transmission lines or connectors, which support
multiple, quasi-TEM modes of propagation, it is often desirable to compute
the Terminal S-Parameters.
To calibrate a Wave Port, that has already been defined, with Terminal
Lines:
1. From the Project Tree,
Tree expand Excitations and double click on the
Wave Port to be calibrated
2. Select the Terminals tab.
3. From the table, select the Terminal Line column for the first terminal
and choose New Line.
Line
4. Enter the position and length of the line using one of the following
methods
Type the start and stop points of the line directly into the x, y,
or z axis fields, referenced to the working coordinates. For
more information on coordinates, refer to “Getting Oriented in
the Drawing Space” in Chapter **, Drawing Basics and Tips.
Graphically pick the points in the Design Window’s graphics
area. The line is displayed as a vector; the vector indicates
direction. From the Terminal Line column, select Swap
Endpoints to reverse the direction of the line, if necessary.
5. Repeat steps 3 and 4 to define and apply lines to other terminals of
the current Wave Port.
6. Click the OK button when you are finished defining Terminal Lines
7. Repeat steps 1-6 to apply lines to other Wave Ports.
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Excitations
About Terminal Lines
The Terminal S-Parameters represent the linear combination of nodal
voltages and currents for the Wave Port. From the nodal voltages and
currents, the admittance, impedance, and pseudo-S-matrices can be
determined.
By defining a Terminal Line for each conductor across a port, Ansoft HFSS
will automatically convert the Modal Solution to its equivalent Terminal
Solution.
In general a single terminal line is created from the reference or
“ground” conductor to each port-plane conductor.
The polarity reference for the voltage is established by the arrow
head(+) and the base(-) of the terminal line. If you decide to create
terminal lines, they must be defined for every port and every terminal
on the port
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Excitations
Considerations for Defining Wave Ports
Wave Port Locations
It is recommended that only surfaces that are exposed to the background
be defined as Wave Ports. The background is given the boundary name
outer. Therefore a surface is exposed to the background if it touches the
boundary outer. You can locate all regions of outer by selecting the menu
item HFSS, Boundary Display (Solver View). From the Solver View of
Boundaries,
Boundaries check the Visibility for outer.
Interior Wave Ports
If you want to apply Wave Ports to the interior of a structure, you
must create an inner void or select the surface of an interior object
that is assign a perfect conductor material property. Inner voids are
automatically assigned the boundary outer. You can create an inner
void by surrounding one object entirely with another object, then
subtracting the interior object.
Ports are Planar
A port must lie in a single plane. Ports that bend are not allowed. For
example, if a geometric model has a curved surface exposed to the
background, that curved surface cannot be defined as a port.
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1.2
Excitations
Wave Ports Require a Length of Uniform Cross Section
Ansoft HFSS assumes that each port you define is connected to a semiinfinitely long waveguide that has the same cross section as the Wave Port.
When solving for S-parameters, the simulator assumes that the structure is
excited by the natural field patterns (modes) associated with these cross
sections. The following figures illustrate cross sections. The first figure
shows regions that have been defined as Wave Ports on the outer
conductive surface of a structure.
Port 1
Port 4
Port 3
Port 2
In the next figure, cross sections must be added to the structure. The
waveguide on the left is not modeled correctly because it does not contain
a length of uniform cross section at either Wave Port. To model it correctly,
add a length of uniform cross section at each Wave Port, as shown on the
waveguide to the right.
no uniform cross section
at Wave Ports
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uniform cross section
added for each Wave Port
1.2-12
1.2
Excitations
The length of the uniform cross section must be long enough to allow nonpropagating modes to die out. This ensures accurate simulation results. For
example, if a non-propagating mode takes approximately one-eighth of a
wavelength to die out, either because of losses or because it is an
evanescent mode, then you should make the uniform cross section oneeighth of a wavelength. Otherwise, you must include the effects of that
higher-order mode in the simulation.
Discontinuities placed close to the port may also cause non-propagating
modes to reach the port. Placing the port too close to discontinuities will
cause erroneous results since the boundary condition at the port will
prevent the simulated solution from matching the actual solution (i.e. The
system forces the field at each port to be a linear combination of the modes
you request). The energy from the non-propagating modes that reach the
port will affect the apparent energy in the dominate mode and produce
erroneous results.
The modes attenuate as a function of e-αz, assuming the wave propagates
in the z-direction. Therefore, the required distance (uniform port length)
depends on the value of the modes propagation constant.
When the Wave Ports lengths are correct, for modes that are included in
the simulation there is a perfect matched condition at a Wave Port, as if the
waveguide extended to infinity. For modes that are not included in a
simulation, a Wave Port appears as a perfect conductor.
Wave Ports and Multiple Propagating Modes
Each higher-order mode represents a different field pattern that can
propagate down a waveguide. In general, all propagating modes should be
included in a simulation. In most cases, you can accept the default of 1
mode, but where propagating higher-order modes are present you need to
change this to include higher-order modes. If there are more propagating
modes than the number specified, erroneous results will be generated. The
number of modes can vary among ports.
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Excitations
Propagating Modes
Propagating modes are those that have a propagation constant, β (rad/m),
that is greater than their attenuation constant, α (Np/meter). One way to
determine which modes need to be modeled is to set up the problem with
multiple modes and generate a solution with no adaptive passes. Then,
inspect the complex propagation constant, γ = α + β, associated with each
mode. To inspect the complex propagation constant (Gamma) after an
analysis has been performed:
1. From the HFSS, Analysis Setup menu, select Matrix Data.
2. A dialog similar to the one shown below will appear, check Gamma
and change the display type to Real/Imaginary.
Each additional mode at a port results in an additional set of S-parameters.
For example, if you are analyzing two modes at each port in a three-port
structure, the final result is a 6x6 S-matrix. In general, an n-port solution is
the total number of excitations of all ports, the number of modes, plus the
number of sources.
If you choose not to include some higher-order modes in a simulation,
make sure the cross sections on the Wave Ports are long enough so that
the modes die out and are not reflected back.
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Excitations
Wave Ports and Symmetry Planes – The Impedance Multiplier
When a ports size is reduced because of a symmetry plane, the impedance
needs to be adjusted to account for the loss of voltage and power-flow.
A Perfect E Symmetry plane must be adjusted by a factor of 2.
Such models have half the voltage differential and half the
power flow of the full structure, resulting in impedances that
are half of those for the full structure.
A Perfect H Symmetry plane must be adjusted by a factor of 0.5.
Such models have the same voltage differential but half the
power flow of the full structure, resulting in impedances that
are twice those for the full structure.
If the structure has a combination of Perfect E and Perfect H
Symmetry planes, adjust accordingly.
For instance, you do not have to enter an impedance
multiplier for a structure with both a Perfect E and Perfect H
boundary since you would be multiplying by 0.5 and 2.
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2
Analysis Setup
Analysis Setup
This chapter provides details on Analysis in the Ansoft HFSS v.10.0 software
such as:
Add Solution Setup
Adapt Frequency
Convergence Criteria
Initial Mesh Options
Adaptive Options
Low-Order Basis Functions
Setup
Properties
Add Sweep
Sweep – Properties and Types of Sweeps
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Analysis Setup
Adaptive Meshing
The adaptive meshing constructs a mesh that conforms to the electrical
performance of the device. By employing adaptive meshing, the mesh is
automatically tuned to give the most accurate and efficient mesh possible.
Without adaptive meshing, the responsibility of generating the correct mesh
would be left to the user. This is both error prone and tedious. With Adaptive
Meshing you will know the answer is right the first time.
How it Works
The adaptive meshing algorithm searches for the largest gradients in the Efield or error and sub-divides the mesh in those regions. It also targets
singularities, such as the edge of a conductor, as locations to add extra
elements.
The mesh growth for each adaptive pass is controlled by the Tetrahedron
Refinement in Setup Solution (Advanced Tab).
Tab) You should notice, that the
Tet.
Tet. Refinement is a percentage. This ensures that between each pass the
mesh is sufficiently perturbed and guarantees that you will not receive false
convergences.
After the mesh has been refined, a full solution is performed and the
process is repeated until convergence
Convergence
After each adaptive pass, HFSS compares the S-Parameters from the
current mesh to the results of the previous mesh. If the answers have not
changed by the user defined value or Delta S, then the solution has
converged and the current or previous mesh can be used to perform a
frequency sweep. If the solution has converged, then technically, the
previous mesh is as good as the current mesh. In this case, Ansoft HFSS
will use the previous mesh to perform frequency sweeps if they have been
requested.
Delta S
The Delta S is the default criteria used to determine mesh/solution
convergence. The Delta S is defined as the maximum change in the
magnitude of the S-parameters between two consecutive passes:
Maxij[mag(SNij – S(N-1)ij)], where i and j cover all matrix entries and N
represents the pass number
Since this is the magnitude of a vector quantity, it can vary between
0 and 2
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Analysis Setup
Adaptive Meshing (Continued)
Since the adaptive meshing is based on the E-field, choosing the proper adapt
frequency can be critical. Like anything in engineering, there are exceptions to
every rule, but in general, the following tips will help you select the correct
adaptive frequency.
Broadband Structures
For broadband structures, the end frequency should be used since the finer
mesh should be valid at all lower frequency points.
Filters
For filters or narrow-band devices, a frequency within the pass-band or
operating region should be used since in the stop-band the E-field is only
present at the ports.
Fast Frequency Sweeps
For Fast Frequency Sweeps, typically use the center of the frequency
band. The Fast Frequency Sweep uses the mesh/solution at the adaptive
frequency point. Since the error in the Fast Frequency Sweep typically
increases as you move away from this point, the center of the frequency
band is usually the preferred solution frequency to extrapolate the entire
band from. It is also important to center the frequency sweep around a
center point that will produce an adequate mesh. This is especially true for
very high Q devices such as narrow-band filters. If the center frequency is
not in the filters pass-band, the bandwidth and resonant frequency will not
be accurate.
Full-Wave Spice Export
For Full-Wave Spice problems, use the Knee Frequency
(Fknee≈0.5/rise_time) to adapt to convergence. Then perform 2-5 more
frequency points to adapt at. The additional points should be selected
between the Knee Frequency and the maximum frequency (Only needs 2-3
passes per frequency point).
Frequencies below the Knee Frequency should have the largest
impact on the time-domain, therefore the Knee Frequency is used
for the primary adaptive meshing. Unfortunately, the mesh needed
at the higher frequencies may not be resolved enough without
performing the additional adaptive mesh passes.
Due to the large bandwidths, typically you will use an Interpolating
Sweep. Using multiple frequency sweeps and combining the results
may also be useful.
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Analysis Setup
Adaptive Meshing (Continued)
High-Speed Digital/Signal Integrity
For high-speed digital simulations you are interested in the performance
over a broad frequency range. To determine the frequency bandwidth that
you need to simulate over, the following guide is recommended:
BW ≥ 5*Fknee, where Fknee ≈ 0.5/rise_time
In general, all of the frequencies below the Fknee frequency have the largest
impact on the digital signal. Therefore a good high-speed digital design will
have a clean, well matched response up to at least Fknee.
High-Speed Digital (SPICE Export)
To export to SPICE, for transient simulations, a large bandwidth is required
(≥5*Fknee). The reason for this is that the Fknee is an approximation, plus you
want more then 1 sample point over the rise-time.
When exporting to SPICE, the low frequency is also important. You want
to get as close to DC as possible. Every port setup and every problem is a
little different with regards to how low you can solve in Ansoft HFSS. 99%
of the time you can simulate to at least 100MHz. Below that is trial an
error. When you export to Full-Wave SPICE, the DC component will be
extrapolated from the lowest frequency in the solve. Therefore, going from
1GHz to DC is not going to give a very accurate extrapolation.
Frequency spacing. The setup for Full-Wave Spice recommends that the
minimum frequency be used as the spacing. This usually results in 10003000 points depending on the bandwidth of the sweep.
High-Speed Digital (Adaptive Meshing)
Since the simulation bandwidths can be so large, determining the proper
adaptive mesh frequency can be very difficult. The following technique is
recommended:
1. Adapt at the Fknee until convergence (Delta S 0.02 to 0.01)
2. Pick 2-3 frequency points above Fknee to adapt at
Don’t run these to convergence, just do 3-5 passes
3. Solve the Frequency Sweep
For large bandwidths, either break up the frequency sweep
and/or use Interpolating Sweeps
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Analysis Setup
Adaptive Meshing (Continued)
High-Speed Digital (Why this technique?)
If the frequency points below Fknee have the biggest impact on the digital
response, then meshing at that frequency should produce an accurate
mesh for all frequency points below it.
If you simulate most passive devices over a large enough bandwidth, they
start to exhibit a low pass filter response. So the higher frequency content
contributes less to the time-domain simulation in addition to being filtered
out by the devices frequency response. This is why we don't worry as
much about the higher frequency adaptive passes converging. To
appreciate the significance of this you also have to take into account how
HFSS does its adaptive meshing. It is done by finding the highest gradient
of the electric field. So if the device behaves as a filter and we are
adapting outside the pass band of the filter, we are focusing most of the
mesh only at the ports.
Now if your device performs well beyond Fknee, there is no harm in
adapting at a higher frequency until convergence. Unfortunately, for real
problems(10-40Gb/s) the design challenge is to get the device to work at
least up to the knee frequency.
For these large Bandwidth sweeps, use the Interpolating Sweep. This
sweep is based on the discrete sweep, but it adaptively picks discrete
points and curve fits. So it takes less discrete points to represent a large
bandwidth. The interpolating sweep can use either a polynomial fit or a
rational function. So it can help to break up the sweep. Up to the knee
frequency works good for a polynomial fit and above that the rational
function will work better. The interpolation sweep will always pass through
the start/end frequency points so if you don't change the mesh and make
sure the start and end frequency points match up for your sweeps, they
combine together without a problem.
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Analysis Setup
Adaptive Meshing (Continued)
High-Speed Digital (Design Flow)
Up until this point, the entire discussion of High Speed Digital was based
on the assumption that you are exporting every simulation to SPICE.
There are many stages in the design cycle and going to SPICE is not
required for every part of the design. If you have resonance's, mismatch,
coupling, etc below the Fknee, these should be addressed in the field
solver prior to running SPICE simulations. Therefore, the sweep only
needs to be done to 1.5-2x Fknee to investigate the performance. In
addition, for engineering design purposes, you may not need to go below
1GHz.
During these early stages of design, you may also want to use the Fast
Frequency Sweep since you can get S-Parameters and fields for every
frequency in the Sweep. This allows you to visualize any resonance or
coupling you may be seeing in the S-Parameters.
Another useful tool for package/board analysis is the EigenMode solver. In
many instances, resonances caused by the power and ground plane nets
are the largest contributor to designs problems. By removing everything
except the power/ground nets, the Eigenmode solver can be used to
quickly identify resonances.
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Analysis Setup
HFSS v10 Mesh Algorithm Improvements
Fault Tolerant Meshing
HFSS v10 introduces new feature when it comes to meshing 3D
geometries. It is called Fault Tolerant Meshing. By default the Classical
mesh maker is still default mesh maker since it has been improved over the
years. If the classical mesh maker fails Fault Tolerant mesh maker will get
invoked. You will notice that mesh3D_init_FT line in your profile file
whenever Fault Tolerant mesher gets invoked. By default if the classical
mesh maker was used the profile file will contain only mesh3D_init line.
Model Resolution length (MRL)
The model resolution length can be thought as a post initial mesh feature. It
is a feature that could not be supported in the classical mesh maker. So if
the user set the MRL, only the Fault Tolerant mesher will be used. Model
resolution length enables model convergence. In the previous versions of
HFSS the number of tetrahedrons as a basic mesh element could get too
large so the solver would run out of memory. With the MRL we are able to
reduce the number of tetrahedrons using a less memory resources while
keeping he same accuracy as before.
MRL Default values
The model resolution length is the length to which mesh will resolve the
model. The default values are 100 times the absolute resolution length
(ResAbs) used by ACIS. ACIS uses 1.0 e-6 user units as the default
ResAbs. Recommended values are of on the order of 0.1 to 0.05 of your
wavelength. You can simply start with values from 0.1 and then try 0.01
and 0.001 and see if they improve the mesh sizes. If the user specifies the
length that the mesh grossly misinterprets the model or changes the
contacts between the objects HFSS will detect this and report this as an
error ( “ MRL too large or object_name lost all surface triangles”)
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Analysis Setup
Setting Convergence
It is very common to request too much accuracy when defining the Delta S.
Remember! The manufacturing process, the laboratory equipment, and the
measurement process all have inherent errors associated with them. Asking
HFSS to provide a level of accuracy that is orders of magnitudes greater then
what you can obtain in the real-world does not buy you anything other then extra
simulation time. Instead, use the Convergence Monitoring and good engineering
judgment to determine when to terminate the adaptive meshing process and how
to set the Delta S. In general a Delta S of 0.02(2%), which is the default, or as
low as 0.01(1%), is sufficient.
Solution Convergence – S-Matrix vs. Fields
The convergence criteria is based on the S-Matrix. Typically, the S-Matrix
converges prior to field quantities. That is to say if you are looking for the
absolute field value within the problem region, chances are you will need to solve
several more adaptive passes in order to see the same convergence that was
obtained for the S-Matrix. This will also depend on the field quantity you are
solving for. Ansoft HFSS solves for the E-field directly. From the E-field it
calculates the H-field and from the H-field it calculates current. Therefore, the
field quantities will also converge with varying mesh densities.
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Analysis Setup
Adding a Solution Setup
In order to perform an Analysis in Ansoft HFSS a Solution Setup must be added.
To do this, right click on Analysis in the Ansoft HFSS model tree.
By default, the General Tab will be displayed. The Solution Frequency and the
Convergence Criteria are set here.
Enabling/Disabling a Solution Setup
When adding a new solution setup, by default, it will be enabled. To disable any
setups, right click on the setup and remove the check mark next to Enable by left
clicking once. Once a solution is disables, it will be grayed out in the project tree.
To enable a disabled project, right click on the disbaled setup and place a check
mark next to Enable by left clicking once.
Enabled
Disabled
Enabled
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Analysis Setup
Adding a Solution Setup (Continued)
General Tab
Solution Frequency – This frequency point is used by the adaptive mesher
to automatically refine the mesh to electrical performance of the device.
Solve Ports Only - The Port Solution uses an arbitrary, adaptive 2D
eigenmode solver to determine the natural frequencies or modes
that will be used to excite the structure. The ports only solution can
be used to calculate only the modal field patterns for the 2D cross
sections defined to be ports. This is useful for determining the
number of modes, modal fields, the port length, and/or proper port
setup prior to running a full solution.
Adaptive Solutions
Maximum Number of Passes - This number controls the maximum
number of passes the adaptive mesh routine will perform as it
attempts to satisfy the convergence criteria.
Maximum Delta S Per Pass – This number defines the convergence
criteria for the adaptive meshing process.
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Analysis Setup
Adding a Solution Setup (Continued)
Options Tab
Initial Mesh Options
Lambda Refinement - The Initial Mesh is based only on the 3D solid
model, it has no bearing on the electrical performance of the device
to be simulated. The Lambda Refinement process refines the Initial
Mesh until most mesh element lengths are approximately onequarter wavelength for air and one-third wavelength for dielectrics.
A wavelength is based on the Single Frequency value entered in the
Solution Frequency.
Frequency In almost all cases Lambda Refinement should
be used.
Use Free Space Lambda – This will force the lambda refinement to
target a mesh size approximately one-quarter of a wavelength for
air. The material properties of objects will be ignored. This may be
useful in applications that have dielectrics with very high
conductivities. Brain tissue or salt water are examples of materials
that will produce very high mesh counts even though the RF
penetration into the material will be limited to a region very close to
the surface.
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Analysis Setup
Adding a Solution Setup (Continued)
Options Tab
Adaptive Options
Refinement Per Pass -The mesh growth for each adaptive pass is
controlled by the Refinement Per Pass. The Refinement Per Pass is
a percentage. This ensures that between each pass the mesh is
sufficiently perturbed and guarantees that you will not receive false
convergences.
Minimum Number of Passes - An adaptive analysis will not stop
unless the minimum number of passes you specify has been
completed, even if convergence criteria have been met
Minimum Converged Passes - An adaptive analysis will not stop
unless the minimum number of converged passes you specify has
been completed. The convergence criteria must be met for at least
this number of passes before the adaptive analysis will stop
Use Matrix Convergence - You can specify different stopping criteria
for specific entries in the S-matrix. This is done by checking the Use
Matrix Convergence box. The adaptive analysis will continue until
the magnitude and phase of the entries change by an amount less
than the specified criteria from one pass to the next, or until the
number of requested passes is completed.
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Analysis Setup
Adding a Solution Setup (Continued)
Options Tab (Continued)
Use LowLow-Order Solution Basis – The Low Order Basis Functions reduce the
default second-order basis function to a linear basis function. It is intended
for simulations in which the edge to edge spacing between tetrahedron is
electrically small. In this situation, the basis function, and hence the
number of unknowns, can be reduced. For this assumption to be valid, the
edge lengths for all tetrahedron in the model should be on the order of
1/20th of a wavelength. In versions prior to v10.0, this was set with a
system environment variable called ZERO_ORDER.
Common Applications :
On-Chip Spiral Inductors, Capacitors, Transformers, etc.
Package Analysis – Flip-Chip, BGA, etc.
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Analysis Setup
Adding a Solution Setup (Continued)
Advanced Tab
Port Adapt Options
Port Field Accuracy - Usually, the default Port Field Accuracy value
is adequate. You may want improved port accuracy under the
following conditions:
You are interested primarily in the port impedances. Port
impedances are computed as part of the port solution.
You need to lower the noise floor to catch S-parameters that
are expected to be in the -70 dB range.
Refining the mesh at the ports causes HFSS to refine the mesh for
the entire structure as well. This occurs because it uses the port field
solutions as boundary conditions when computing the full 3D
solution. Therefore, specifying too small a port field accuracy can
result in an unnecessarily complex finite element mesh
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Analysis Setup
Adding a Solution Setup (Continued)
Solution Setp (Continued)
Set Min/Max Triangles
The mesh for each model port will be adaptively refined until it
includes the minimum number of triangles. Refinement will then
continue until the port field accuracy or the maximum number of
triangles is reached.
To specify the minimum and maximum number of triangles in
the port mesh, uncheck the Automatically Set Min/Max
Triangles option.
Enter a value for the Minimum Number of Triangles.
Triangles The
default value is 25 for models with lumped gap ports and 90
for models with wave ports.
Enter a value for the Maximum Number of Triangles.
Triangles The
default value is 400.
If you leave Automatically Set Min/Max Triangles selected, HFSS
will determine the reasonable values for the minimum and maximum
number of triangles based on the port’s setup.
Defaults Tab
The Defaults tab allows you to save the current settings as the defaults for
future solution setups or revert the current settings to the standard setting.
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Analysis Setup
Frequency Sweeps
Using the converged mesh or initial mesh if no adaptive passes were requested,
the swept frequency response of the device can be obtained. Ansoft HFSS
provides several methods for calculating the frequency response:
Discrete – performs a full solution at every frequency using the current
mesh. The time required is the single frequency solve times the number of
frequency points. Fields can be displayed at any frequency within the
sweep range if the Save Fields Box is checked.
Fast – uses an Adaptive Lanczos-Pade Sweep(ALPS) based solver to
extrapolate an entire bandwidth of solution information from the center
frequency. Very good for high-Q devices but it can not be used to solve for
devices that pass through cut-off. Once the band has been extrapolated, a
high number of frequency points can be calculated without a penalty. In
addition, the Fields can be displayed at any frequency within the sweep
range. The time and memory required to solve a fast frequency sweep
may be much larger then the single frequency solve.
Interpolating – performs solves at discrete frequency points that are fit by
interpolating. Ansoft HFSS determines the frequency points to solve at
based on the error in the interpolation between consecutive passes. The
interpolation error and maximum number of points is defined by the user in
the Edit Sweep. As with the fast frequency sweep, the Interpolating Sweep
can generate a larger number of frequency points. But you only have the
field solution for the last solved frequency. The maximum solution time is
the single frequency solve times the maximum number of points.
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Analysis Setup
Add Sweep
After a Solution Setup has been added you can also add a Frequency Sweep.
To do this, right-click on Setup in the HFSS Model Tree. The Edit Sweep window
will appear
Sweep Type
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Analysis Setup
Add Sweep (Continued)
Frequency Setup
After the sweep type has been chosen, the frequencies of interest must be
specified.
There are three Frequency Setup Options:
Linear Step -- specify a linear range of values with a constant step size
Linear Count -- specify a linear range of values and the number, or count,
of points within the variable range
Single Points -- specify a single values for the sweep definition
Saving Fields
It is possible to save the Field data for every point in the Fast Sweep and
the Discrete Sweep. To save the Field information make sure that the
Save Fields (All Frequencies) box is checked.
For the Interpolation Sweep, only the Field data for the last solved
frequency will be available for post-processing.
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Analysis Setup
Add Sweep (Continued)
DC Extrapolation Options
When exporting Spice subcircuits it is necessary to include the DC point.
Since Ansoft HFSS does not solve down to DC we can use DC
Extrapolation. The DC Extrapolation option is available in the Discrete and
Interpolating Sweeps.
Time Domain Calculation
Ansoft HFSS can calculate the maximum frequency required to obtain an
accurate time domain result. HFSS uses the following equation:
Max. Freq. = (0.5/Signal Rise Time) x Time Steps Per Rise Time
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Analysis Setup
Frequency Sweeps (Continued)
Adding Points to a Fast or Interpolating Sweep
After the Fast or Interpolating sweeps have completed, additional
frequency points can be added by changing the number of points in Edit
Sweep Clicking on Analyze will not resolve the entire frequency sweep, it
will just calculate the additional frequency points.
Adding Solutions to Interpolating Sweeps
If the interpolating sweep does not converge with the requested passes or
you wish to change the target convergence, the values can be changed
and resolved. The interpolating sweep will recalculate the two end
frequencies but after that it will use the previously calculated points and
continue trying to reach the target convergence.
Ports Only and Frequency Sweeps
A discrete or interpolating frequency sweep can be used with the Ports
Only solution.
Fast Frequency Sweep Ports Solve
The Fast Frequency sweep can not be used on ports that pass through cutoff. You may also experience problems if the sweep frequency approaches
cut-off.
Combining Multiple Frequency Sweeps
For very large bandwidths, breaking the band into smaller frequency
sweeps can improve the results. Since the Fast Frequency Sweep is
extrapolated from the center frequency different error curves at the end
frequencies will prevent the sweeps from aligning. The interpolating sweep
will not have this problem since the solution always passes through the end
frequencies (Assuming the same mesh is used).
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Analysis Setup
Enhancements and New Features
Mesh Re-use
Copy geometric equivalent meshes – For optimetrics analysis setups you
can request HFSS to copy a mesh that was calculated for one sweep
variation for reuse on a geometrically-equivalent sweep variation.
Initial Mesh Options
Use mesh from current design – enables the use of a
mesh from a previous setup.
Use mesh from other project – enables the use of a
mesh from another model that has the same geometry
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Analysis Setup
Enhancements and New Features
Matrix Convergence Options – allows the ability to define other convergence
criteria
Output Variable Convergence – Allows the creation of an output variable to
be used for the convergence criteria. In order to use this, an output variable
expression has to be created, then this field will become active
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Ansoft HFSS Data Reporting
Overview
Ansoft HFSS has very powerful and flexible data management and plotting
capabilities. Once understood, it will make the whole solution process much
easier, and will help craft the entire problem setup.
Topics of Discussion
Data management
2D Plotting
3D Plotting
Antenna characteristics
Field Plotting
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Data Management
With every model variation that is solved, a new data entry is stored within the
project results directory. This capability has implications in that the user can
perform a parametric sweep of a model without needing an Optimetrics license.
NOTE: Automatic parametric sweeps along with the other Optimetrics
functions, Optimization, Sensitivity, and Statistical analyses, DO require an
Optimetrics license.
The dataset validity can be checked by selecting HFSS > Results > Browse
Solutions
By examining this dialog, the user can determine which parametric instances
have been solved, and how many adaptive passes were necessary.
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Data Management
Post-processing steps can also be performed in the new interface for HFSS. The
common operations that were previously performed in the Matrix Data module of
previous releases are:
Port Impedance Renormalization
Port DeDe-embedding
Differential pair analyses
Other post-processing operations that used to require the Matrix Data module
that are now computed by default in HFSS version 9.0 are the Y- and ZZ-matrices.
matrices
Also, given that the Solution Type defined early on in the process, negate the
necessity of computing Terminal S-parameters from Modal S-parameters.
Port Impedance Renormalization
Within the new interface, many calculations are made automatically without
user intervention. The wave port renormalization impedances are specified
with the port wizard. By simply editing the properties of a port once a
solution is completed, the port can be re-normalized.
Port DeDe-embedding
This same dialog can be used to change the distance that a port will be deembedded. The user can go back and edit this value as many times as
necessary. Each time the OK button is pressed, the data, and also the plots
if they exist, will be updated with the newly de-embedded data.
Positive values of de-embedding will move the reference plane into the
model
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Data Management
Differential pair analyses
For multiple terminals per port, differential pairs can be created to look at
differential S-parameters instead of single-ended S-parameters. This can
be useful for investigating the possible conversion between differential and
common mode within a given structure.
Within the wave port dialog, the Differential Pairs tab controls the creation
of the pairs from the individual Terminals
1. To create a differential pair, select New Pair,
Pair and select the terminal
lines that represent the positive and negative sides
2. From here, you can also change the Differential and Common mode
impedance setting for each pair.
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Data Management
Importing Data from other solutions
Often it is desirable to compare the results of one simulation to the results
of another simulation, HFSS, circuit, or planar, or even measurements.
This can be accomplished readily within the HFSS version 9.0 desktop
environment.
To import solutions into HFSS Desktop:
NOTE: The minimum requirements for importing a solution are an
existing model with at least one port.
1. Select HFSS > Results > Import Solutions, and the following dialog
will appear:
2.
The import options are Import Solutions and Import Table.
Table
Solutions represent S-parameter matrices in standard forms
such as Touchstone and Ansoft legacy data in .szg file
format. Tables are simply files containing rows and columns
of data.
Selecting Import Solution will bring up the following dialog:
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Data Management
From this window, select Browse to find the file to be imported. The
acceptable file formats are: .sNp, .szg, .flp, .yNp, .zNp, and .tou.
4. Click Open to load the file.
5. Click Import to bring the data into the HFSS desktop
6. Click OK when you are done importing solutions
All solutions will appear in the report editor under the Sweep category
(more on this later)
3.
For Import Table, the following dialog will appear:
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Plotting Data
Data plotting can take a variety of forms. The most often used format is 2D
Cartesian plotting, but we also have the capability to plot in 3D as well. Below is a
list of all the quantities that can be plotted on various graphs. For definitions of
each of these quantities, see the online help.
Eigenmode solution
Eigenmode Parameters (modes)
Driven Modal Solution
S-parameters
Y-parameters
Z-parameters
VSWR
Gamma (complex propagation constant)
Port Zo
Driven Terminal Solution
S-parameters
Y-parameters
Z-parameters
VSWR
Power (at port)
Voltage Transform matrix (T)
Terminal Port Zo
Fields
Mag_E
Mag_H
Mag_Jvol
Mag_Jsurf
ComplexMag_E
ComplexMag_H
ComplexMag_Jvol
ComplexMag_Jsurf
Local_SAR (Specific Absorption Rate)
Average_SAR
NOTE:
NOTE For all Field plots, a polyline or surface must be selected before
creating the Field plot.
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Plotting Data
Types of Plots:
Rectangular Plot
Polar Plot
3D Rectangular Plot
3D Polar Plot
Smith Chart
Data Table
Radiation Pattern
To Create a Plot:
1. Select HFSS > Results > Create Report
2. Select Report Type and Display Type from the selections above
3. Click OK and the Report Editor will be displayed – we will go over the
options in this dialog on the next page.
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Plotting Data
Creating a Plot (cont’d)
4. Context
Design – choose from available designs within a project
Sweep – choose from available sweeps including adaptive passes
and imported data
Domain – defaults to Sweep, but can be switched to Time domain for
plotting S-parameters with an impulse or step response.
5. Sweep / X / Y Tabs
Sweep – controls the source of the independent variable in the plot.
NOTE: By default, the Report editor selects Use Current
Design and Project variable values.
values This will select the
primary sweep of frequency usually, and the current
simulated values of the project variables
To display a plot with multiple traces for different variable
values, change this setting to Sweep Design and Project
variable values You can then change the primary sweep from
frequency to a variable if desired. This is useful for looking at
S21 versus stub length, for example. Simply select the value
in the Name column next to primary sweep,
sweep and change the
value to whatever you desire.
You can also uncheck the All Points block to select which
values of a variable are to be plotted.
X – controls any functional operator on the independent variable
Y – select the value to be plotted and any operator
6. Select Add Trace for as many values as you would like to plot
7. Select Done when finished
An example of a multi-trace plot of the sweep tab shown on the previous page is
shown next
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Ansoft HFSS Data Reporting
Plotting Data
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Plotting Data
3D Plots – simply add a third dimension such that instead of plotting a family of
curves, you can plot a 3D surface that represents your data changing with two
independent variables. Below is a 3D plot of the previous family of curves.
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Ansoft HFSS Data Plotting
Plotting Data
Output Variables
In addition to being able to plot the built-in solved quantities, you can also
create your own by using output variables.
Clicking on the Output Variables button in the Traces dialog shown before,
brings up the following dialog:
To create an output variable:
Type a name into the Name box
Create an equation in the Expression box
Click Add
In the example show above, we have created an output variable that makes
an approximation for Inductance of a spiral inductor. We could also have
created an equation to calculate Q as well.
NOTE:
NOTE These output variables can also be used for optimization.
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Ansoft HFSS – Data Reporting
Data Plotting – Special Case – Antenna Parameters
Since antenna parameters require a special computation setup to determine the
region over which the fields are to be computed, displaying antenna parameters
is a two step process.
Create an Infinite Sphere setup:
1. Select HFSS > Radiation > Insert Far Field Setup > Infinite Sphere
2.
3.
4.
5.
Enter the values and steps for Theta and Phi
You can also change the coordinate system to calculate based upon a
shifted or rotated coordinate system. Select the Coordinate System tab,
and switch to the new CS.
You can also change the Radiation Surface over which the far fields are
computed by simply switching to the Radiation Surface tab, and select a
new surface from any that were previously defined.
Click OK
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Ansoft HFSS – Data Reporting
Data Plotting – Antenna Parameters
Creating a 2D plot:
1. Select HFSS > Results > Create Report
2. Select Far Field form the Report Type pulldown
3. Select Radiation Pattern from the Display Type pulldown
4. Select the quantity to be plotted from the Traces dialog
Note: If multiple Infinite Sphere setups exist, make sure you select
the appropriate one
5. Select Add Trace and Done
For a definition of the available antenna parameters, see the online help
Below is an example of the 2D slices of a patch antenna for LHCP and RHCP
directivity.
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Ansoft HFSS – Data Reporting
Data Plotting – Antenna Parameters
Creating a 3D Plot:
Follow the procedures above for the 3D plot, except change the Phi and
Theta quantities to match the far field calculation. Also choose an antenna
quantity to plot.
Below is an example of a 3D plot for a patch antenna:
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Ansoft HFSS Data Reporting
Data Plotting – Antenna Parameters
Special Case – Antenna Arrays
When using master and slave boundary condition pairs to emulate an
antenna array, you might want to apply an array factor to the computation
of the antenna patterns. This can easily be done in Ansoft HFSS
To create an Antenna Array Factor calculation:
1. Select HFSS > Radiation > Antenna Array Setup
2. Select No,
No Regular,
Regular or Custom Array
3. Switch to the next tab, and enter the characteristics of the array, or
enter the filename that contains the element locations
4. Once you click OK, any plots or calculations that are displayed will
be updated with the array factor calculation. To go back to the single
element calculations, select No Array Setup
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Ansoft HFSS Data Reporting
Data Plotting – Antenna Parameters
Antenna array – Shown below are field patterns of a single element and an array
setup scanned to 30 degree angle.
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Ansoft HFSS Data Reporting
Data Manipulation
Sometimes, the built-in calculated quantities are not adequate even given the
output variable capability. Because of this, Ansoft HFSS has the flexibility built in
with an arbitrary fields calculator.
You can use the Fields Calculator to manipulate field quantities to obtain any
number of values. One common use is to evaluate power flow within a structure.
This can be accomplished by integrating the Poynting vector over a geometric
surface. This can easily be accomplished within the field calculator.
To access the fields calculator:
Select HFSS > Fields > Calculator
For a more detailed explanation of the functions within the field calculator, visit
our online technical support at http://www.ansoft.com.ots
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Ansoft HFSS Data Reporting
Field Overlay Plotting
Previously mentioned was the capability to plot field quantities over a geometry
within a 2D plot, but this doesn’t give us a lot of insight. One of the main benefits
of HFSS is that we can visualize what is going on with the electromagnetic fields
within a structure, something that cannot be measured directly.
Field plots can be applied to geometry selection within the 3D modeler, and can
be modified given different stimulus amplitude, frequency, and phase. We can
also visualize how a field propagates throughout the volume by animating this
plot versus phase, which essentially adds a time base.
To create a 2D / 3D Field Overlay Plot:
1. Select a face of an object, an entire object, or even multiple object
2. Select HFSS > Fields > Plot Fields >
3.
You can then change the frequency of the stimulus or phase with the
resultant dialog box:
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Ansoft HFSS Data Reporting
Field Overlay Plots
Resultant modeler window for Magic “T” model with Mag_E plotted on Global:XY
plane
Selecting the object “arm”, and plotting within the volume yields:
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Ansoft HFSS Data Reporting
Field Overlay Plots
The 3D plot shown on the previous page is called an Isoval surface plot. This is
not the default
To change the field plot type:
1. Selecting: HFSS > Fields > Modify Plot Attributes
2. Switch to the Plot tab
3. Select the applicable Plot from the pulldown
4. Select the IsoValSurface radio button
You can also leave the default of cloud plot and adjust the cloud
density and point size until the plot looks acceptable
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Ansoft HFSS Data Reporting
Field Overlay plots – Source Stimulus
Sometimes it might be desirable to have multiple ports excited at the same time,
perhaps out of phase. This is useful for evaluating power combiners. You might
even want need to calculate the incident or reflected power for a plane wave
source.
To change the Field Plot stimulus:
Select HFSS > Fields > Edit Sources
The following field d overlay plots shows what happens to the Magic “T”
when we have a 90 degree phase shift at the 2 E-plane end inputs. The
component doesn’t isolate one port.
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Ansoft HFSS Data Reporting
Field Overlay Plot – Phase animation
The final step in field overlay plots is creating animation. This essentially shows
you how a wave propagates through the structure as you vary phase (time).
To create an animated 3D field plot:
1. Select HFSS > Field > Animate
2. Typically, you can accept the defaults, but you may want to change the
number of steps to limit computation time.
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Ansoft HFSS Data Reporting
Mesh Overlay Plot
Another plot that can be valuable in evaluating a simulation is the mesh overlay
plot. Once created, you can tell which areas of the structure may need more
tetrahedra for an improved quality of mesh.
To create a Mesh overlay plot:
1. Select the face, plane, or object to plot the mesh
2. Select HFSS > Fields > Plot Mesh
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Ansoft HFSS Data Reporting
Viewing in the 3D modeler
With the ability to plot field quantities and mesh within the 3D modeler, it can
sometimes get crowded, and model details can be obscured by the plots. You
can reduce the clutter by turning off the visibility of objects and even field plots.
To turn off the visibility of field overlay plots:
1. Select View > Visibility
2. Select the Fields Reporter tab, and check, , or uncheck, , the fields plot
you want displayed.
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Solve Loop
Solve Loop
Unlike pre-processing, the solution process is very automated. Once the
problem has been defined properly, HFSS will take over and step through several
stages of the solution process. To start the solution process, right click on
Analysis in the HFSS Model Tree and select Analyze.
Analyze
It is important to review this section since the solution setup has a direct impact
on the automated solution process. A closer look at the solution process reveals
it consists of three components:
Initial Solution – includes the mesh generation, ports solution, and a full
solution at a single frequency
Adaptive Refinement Loop – refines the mesh and performs a full solution at
the Initial solution frequency until convergence
Frequency Sweep – calculates the swept frequency response using a mesh
generated by the Adaptive Refinement Loop
Mesh ReRe-use
Copy geometric equivalent meshes – For optimetrics analysis setups you
can request HFSS to copy a mesh that was calculated for one sweep
variation for reuse on a geometrically-equivalent sweep variation.
Initial Mesh Options
Use mesh from current design – enables the use of a
mesh from a previous setup.
Use mesh from other project – enables the use of a
mesh from another model that has the same geometry
The illustration on the following page outlines the steps performed by the solution
process.
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Solve Loop
Initial Solution
Initial Mesh
Ports Only &
Frequency Sweep
Seeding and
Lambda Refinement
(Single Frequency)
Port Solution
Full Volumetric Solution
(S(S-Parameters/EParameters/E-Fields)
No Adaptive Meshing
Adaptive Mesh Loop
Refine Mesh
(Gradient of EE-Field
at Single Frequency)
No
Check Convergence
(Delta S)
YES
Frequency Sweep
Full Volumetric Solution
(S(S-Parameters/EParameters/E-Fields)
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Solve Loop
Improved Analysis Configuration
Configurable default execution priority
To set this option, go to Tools >
Options > HFSS Options > Solver
Remote Analysis
heterogeneous platform support
Queuing
Queue Projects, Designs, Parametric Sweeps, Frequency Sweeps
To enable this feature, go to Tools > Options > General Options > Analysis
Options > Que all Simulations
To view queued projects, go to Tools > Show Queued Simulations
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Solve Loop
Distributed Analysis
10X Analysis Speed-Up
An automated client-server implementation
little/no overhead
setup easily via remote analysis capability
For Optimetrics instances and partitioned frequency sweeps
An optional license to augment
10 “dependent analyses”
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Solve Loop
Monitoring Convergence
You can view the Convergence of the entire solution process. Right click on
Analysis/Setup in the HFSS model tree. The Convergence Tab can be used to
display a table or a plot.
Matrix Convergence Options – allows the ability to define other
convergence criteria
All – default
Diagonal
Off-Diagonal
Selected Entries
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Solve Loop
Profile
At any time during or after the solution process, you can examine the computing
resources - or profile data - that were used by HFSS during the analysis. The
profile data is essentially a log of the tasks performed by HFSS during the
solution. The log indicates the length of time each task took and how much
RAM/disk memory was required
Task -- lists the software module that performed a task during the solution
process, and the type of task that was performed. For example, for the task
mesh3d_adapt, Mesh3d is the software module that adaptively refined the mesh.
Real Time -- the amount of real time required to perform the task.
CPU Time -- the amount of CPU time required to perform the task.
Memory -- the peak amount of memory used by your machine while performing
the task. This value includes all of the applications running at the time; it is not
limited to HFSS..
Information -- general information about the solution, including the number of
tetrahedra used in the mesh.
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Solve Loop
Matrix Data
After the Solution is complete the Matrix Data can be viewed by clicking on
Analysis/Setup. Right click on Setup and select Matrix Data.
Data The Solution Data
window will appear.
In the Simulation pull-down list, click the solution setup and solved pass adaptive, single frequency solution, or frequency sweep - for which you want to
view matrices.
Select the type of matrix to view.
S-matrix
Y-matrix
Z-matrix
Gamma
Zo (characteristic impedance.)
The available types depend on the solution type
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Solve Loop
Matrix Data (cont.)
Data can be displayed in the following formats:
Magnitude/ Phase
Real/ Imaginary
dB/ Phase
Magnitude
Phase
Real
Imaginary
dB
The available formats depend on the matrix type being displayed.
You can also select solved frequencies that you would like to display
To display the matrix entries for all solved frequencies, choose All Freqs.
Freqs
To show the matrix entries for one solved frequency, clear All Frequencies
and then select the solved frequency that you want to view.
For adaptive passes, only the solution frequency specified in the Solution
Setup dialog box is available. For frequency sweeps, the entire frequency
range is available.
To insert of delete one or more displayed frequencies, click Edit Freqs.
Freqs
This command is only available if the sweep type is Fast or Interpolating. If you
choose to export the matrix data for the Fast or Interpolating sweep after
modifying the frequencies in the Edit Frequencies dialog box, only those
frequencies displayed under the Matrix Data tab will be exported.
Exporting Matrix Data
A number of export formats are available:
Touchstone (*.sNp)
Data Table (*.tab)
Planar EM/HFSS v6+ (*.szg)
Neutral Model Format (*.nmf)
MATLAB (*.m)
Citifile (*.cit)
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Equivalent Circuit Export
It is possible to export Full-Wave Spice, Lumped Element and Partial Fraction
Expansion models from Ansoft HFSS. To do this, click on Analysis/Setup/Matrix
Data/Equivalent Circuit Export.
Export
The Equivalent Circuit Export Options window will appear
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If you have a Driven Terminal solution you can export to PSpice,
PSpice, HSPICE,
Spectre, or Maxwell Spice.
Spice You must have a frequency sweep solution and five
or more frequency points to successfully export an equivalent circuit data file.
Select Lumped Element Export (Low Bandwidth) if you want to save the data as
a low-frequency circuit model using simple lumped elements (resistors,
capacitors, inductors, and dependent current sources).
Select Partial Fraction Expansion for Matlab to create a *.m file
Click Combine Sweeps if you want to combine the data from two or more
frequency sweeps into one file. The end points of the sweep ranges can touch,
but may not overlap.
The S-matrices are written to the data file that you specified in the equivalent
circuit data format.
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Solve Loop
List
To view Model Parameters, Boundaries, Excitations, Mesh Operations and
Analysis Setup right click on Analysis in the Ansoft HFSS model tree and select
List
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4.1
Mesh Operations
Mesh Operations
This chapter provides details on meshing in the Ansoft HFSS v.10.0 software. It
discusses the default meshing of curvature, user control thereof, and the new
volume correction capabilities used in matrix solution. The following topics are
discussed:
Curved Geometry Mesh Adaptation
Faceting Default Settings
Volume Perturbation in FEM Solutions
User-Defining Surface Approximations
Application Recommendations
Model Resolution
Applying Mesh Operations
Examples/Benchmarks
The following examples are provided to demonstrate the topics discussed
in the chapter:
Standard Pillbox Resonator
Hemispherical Dielectric Resonator Antenna with Cavity
Accelerator Spoke-Cavity Application
Circular WG Quadrature Ortho-mode Junction (OMJ)
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Mesh Operations
Curve Mesh Adaptation in HFSS v10.0
HFSS v10.0 meshes handles curved surfaces differently than prior versions of
HFSS. Proper understanding of the differences in curved mesh handling and the
advantages of new capabilities in the HFSS v10.0 solver are essential to
obtaining accurate results.
The new graphical drawing interface encourages the use of true-curved
drawing, by removing the option to assign a facet count to the construction
of primitives such as circles, cylinders, spheres, and ellipses.
Faceted primitives are available however as polyhedrons and
polyhedral solids, if still desired.
Initial meshing is constrained by faceting decisions made by the first pass
of the meshing algorithms. In prior versions of HFSS however, adaptive
mesh points could be placed ‘anywhere’ on the true-surface of the affected
object(s), as shown in the before and after images below. (Initial mesh left,
adapted at right. Note that regular faceting was not maintained after
adaptive mesh alteration.)
For HFSS v10.0, however, in order to provide more robust meshing with
respect to more complex geometries, the initial faceting selections made
for curved objects are respected throughout the adaptation process, so that
the adapted mesh is a subdivided variation of the same meshed volume as
the initial mesh. An adapted mesh from HFSS v10.0 is shown below.
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4.1
Mesh Operations
Faceter Default Settings
In order to keep initial meshes at reasonable sizes, the initial faceting default
setting is to constrain the mesh surface normals to fall within 30degrees of the
true-curved surface normals.
This means that a cylindrical surface would be ‘faceted’ into 16 segments
about its circumference, as illustrated below.
The normal for each flat segment cannot be off by more than 30 degrees
from the normal for the curved true surface which that segment’s face is
approximating.
Although aided by the Volume Perturbation technique now used in HFSS
v10.0, it is not anticipated that this default faceting will be ‘enough’ for
extremely high-accuracy analysis of resonant cavity volumes, spheroids,
etc.
The faceting default does not include a stringent aspect ratio default (note
long triangles on top and bottom cylindrical faces).
The default however is sufficient for most applications in which the curved
geometry is not itself highly critical to the simulation result, yet where more
faceting would result in an extremely large initial mesh
E.g. Applicable for:
…meshing of transmission line models with both signal and nonsignal vias present to prevent parallel-plate modes in stripline or
CPW configurations
…Coaxial applications, where both the inner and outer radius faceting
maintains an effectively congruent distance for characteristic
impedance results.
…cylinders or spheres used as radiation boundaries.
Less Applicable for:
….cylindrical cavity resonances to 0.001% frequency accuracy
…elliptical waveguide coupling irises
…circular waveguides
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4.1
Mesh Operations
Introduction of Volume Perturbation to HFSS Solutions
Despite lower faceting ‘compliance’ to the true-curved geometry as the
adaptation process adds mesh points, HFSS v10.0 introduces a new solution
technology that should result in a more accurate solution from far smaller mesh
counts than in prior versions. This technology is referred to as Volume
Perturbation or Volume Correction.
Correction.
In a faceted mesh of a cylindrical solid, small arc-section volumes are ‘lost’
to the cylinder volume and become part of the volume of the cylinder’s
surroundings.
Since the true geometry definition is known before faceting, the deltavolumes represented by each of these sliver regions is computable
The meshing algorithm in HFSS v10.0 can provide ‘adjustment factors’ to
both the tetrahedral center-edge node locations and to the appropriate
volumes of the tetrahedra on either side of the curved boundary, so that the
FEM solution proceeds with the right terms even for a loosely-discretized
mesh
The end result is higher accuracy from the same mesh, even before the
benefits of adaptive mesh refinement are taken into account.
Volume Perturbation solutions are always on. No user setting is required to
active them.
Sliver Region (only top surface
mesh outline shown)
Ansoft High Frequency Structure Simulator v10 User’s Guide
4.1-4
4.1
Mesh Operations
User Control of Curved Mesh Faceting
Since Volume Perturbation alone is not always enough, users can control the
fidelity to which the initial mesh faceting conforms to geometric curvature by
assigning Mesh Operation Surface Approximations to appropriate objects and/or
object faces
Mesh Operations can be assigned from the HFSS menu, from the Design
Tree,
Tree or from the geometry interface’s context-sensitive menu.
The Surface Approximation options are shown below right. Definitions
follow:
Surface Deviation is the maximum spacing,
in drawing units, that the tetrahedral surfaces
may be from the true-curved geometry’s
surface.
Normal Deviation is the maximum angular
difference, in degrees, that a tetrahedral
face’s normal can have from the surface
normal for the true geometry which it is
meant to represent.
Aspect Ratio refers to the maximum allowed
aspect ratio of all faces of all tetrahedra of
the selected object or face. This setting
influences mesh quality rather than actual
meshed volume or surface locations.
Ansoft High Frequency Structure Simulator v10 User’s Guide
4.1-5
4.1
Mesh Operations
Each Setting can be forced, left at the default, or turned off entirely
Ignore means no evaluation of this
constraint will be done in generation of
the initial meshing, not even to the
“built-in” settings HFSS follows without
surface approximation instructions
Use Defaults leaves that constraint at the
built-in settings, and is selected if you do
not wish to tighten this constraint but also
do not wish to deactivate it.
Set… is of course used to apply a user
constraint value which may be tighter or
looser than the built-in constraint used
in the absence of specific instructions.
Setting looser constraints than the
default may require also setting
adjoining objects to the same
looser constraint so that the
default does not take precedence
at interfaces.
Usage Suggestions
Do not overspecify.
overspecify.
It is always easier to ‘add’ than subtract mesh, by running more adaptive
passes or by adding supplemental mesh instructions
Too stringent a setting (e.g. Normal Deviation of 1 degree) can result in
poor mesh qualities due to aspect ratios, poor mesh gradients to
surrounding objects, etc.
Use Aspect Ratio settings along with Normal or Surface Deviation settings
For cylindrical type objects where curved and planar faces meet, the
normal and surface deviation settings apply to the curved faces only.
Setting an aspect ratio limit as well (e.g. 4:1) will force a few additional
triangles on the planar faces and help preserve a cleaner overall mesh
Consider using Polyhedrons or Polygons instead if using to ‘reduce’ mesh
If your design has many curved objects which you want only very coarsely
meshed (e.g. a whole fence of ground vias, for which 30 degree default
normal deviation is unnecessary), and the geometry is not imported,
consider drawing the vias as hexagonal or even square solids instead,
rather than having to ‘remember’ to reduce the meshing fidelity on them all.
Ansoft High Frequency Structure Simulator v10 User’s Guide
4.1-6
4.1
Mesh Operations
Model Resolution
Model resolution enables model convergence and reduce solve times. If in
previous versions the tetrahedron count got too large, the solver could run out of
memory. It would be trying to add meshing elements to areas of the model that
are not important. Now with model resolution, we are able to crank down the
mesh size in order to actually get convergence before memory becomes an
issue.
Model resolution is a length based value that modifies the initial mesh. This
meshing operation allows the user to specify a minimum edge length of any
tetrahedron used for the mesh. By specifying a minimum edge length for a
tetrahedron, the mesher will have to coarsely mesh geometric detail that may not
be electrically important. This saves the solver a tremendous amount of solution
time since the initial mesh is smaller, and the mesher does not have to add mesh
elements to areas that are not electrically important.
When dealing with models that have very high aspect ratios due to small
geometric detail, use a model resolution of 1/10 to 1/20 of the thinnest conductor
to start with. Then adjust the value accordingly.
A Complex Connector
Enabled Convergence
(previously unsolvable)
one half the mesh
two thirds the memory
one third the time
Ansoft High Frequency Structure Simulator v10 User’s Guide
4.1-7
4.1
Mesh Operations
Model Resolution Con’t
Practical Example
This is part of a complex design that benefited from model resolution. The
grey outline is the reduced model. The pink lines were the original model
details that were removed due to the mesh operation. The original model
had an initial mesh of 184,675 tets. After model resolution, the initial mesh
was 24,691 tets.
Ansoft High Frequency Structure Simulator v10 User’s Guide
4.1-8
4.1
Mesh Operations
Applying Mesh Operations
If you want to refine the mesh on a face or volume but don’t want to generate a
solution, do the following after defining mesh operations:
If a current mesh has been generated, HFSS will refine it using the defined
mesh operations.
If a current mesh has not been generated, HFSS will apply the mesh
operations to the initial mesh.
If an initial mesh has not been generated, HFSS will generate it and apply
the mesh operations to the initial mesh.
If the defined mesh operations have been applied to the selected face or
object, the current mesh will not be altered.
Define a new mesh operation rather than modify an existing mesh
operation. HFSS will not re-apply a modified mesh operation. Applying
mesh operations without solving enables you to experiment with mesh
refinement in specific problem regions without losing design solutions. You
cannot undo the applied mesh operations, but you can discard them by
closing the project without saving them.
Ansoft High Frequency Structure Simulator v10 User’s Guide
4.1-9
4.1
Mesh Operations
Source: (Canonical)
Description
A pillbox resonator is a simple cylindrical cavity, the exact resonance of which is
solved analytically as:
f
TE mnp
r
f
TM mnp
r
c
= ε
2
c
= ε
2
2
 qnm
p2 
+ 2

2
l 
(
)
π
b

2
 pnm
p2 
+ 2

2
l 
 (πb )
Equations for TE and TM modes of order (n, m, p) where p is the
number of half-wave variations in the cavity axis direction
pnm and qnm represent the zeros of the Bessel functions or their
derivatives
b is cavity radius, and l is cavity height
cε is the speed of light in the enclosed volume media
Benchmark
A pillbox project with b = 10 cm and l = 10 cm was constructed.
Volume of cavity was vacuum; wall boundaries were perfect conductors
Solution was requested for 3 eigenmodes, with Surface Approximations set to
vary the Normal Deviation
norm was varied from 5 to 45 degrees by 5 degree steps
Aspect ratio was set at 5:1; Surface Deviation setting was “Ignore”
Solution setup was 0.25 GHz starting frequency (to assure a starting
frequency did not add mesh beyond those set by the surface approximation
settings
Solutions were continued to 0.01% delta-f (real part) or 10 passes,
whichever came first
Tabulated results vs. theoretical computations are shown on the page following
Bessel zeros were computed to about 5 digits (e.g. p11 = 1.84118)
Speed of light used was 299792458 m/s
Ansoft High Frequency Structure Simulator v10 User’s Guide
4.1-10
4.1
Mesh Operations
Results:
Normal
Deviation
(deg)
5
10
15
20
25
30
35
40
45
HFSS
TM010
Result
(GHz)
1.147406
1.147345
1.147124
1.146748
1.146623
1.146196
1.145602
1.144962
1.144962
HFSS
Delta vs.
TE111
Theory
Result 1
(%)
(GHz)
0.001482 1.7361
0.006798 1.73307
0.026058 1.72758
0.058827 1.7192
0.069721 1.71165
0.106935 1.69707
0.158703 1.68868
0.214481 1.67654
0.214481 1.67654
HFSS
TE111
Result 2
(GHz)
1.736118
1.733154
1.727638
1.719607
1.712348
1.697355
1.688798
1.677916
1.677916
Avg.
Final
Final Delta-f
Delta vs.
Tetrahedra Convergence
Theory
Count
(%)
(%)
0.0756005
3347
0.0067755
0.2480399
2670
0.0077428
0.5647448
1882
0.022301
1.0370537
1060
0.042848
1.4632887
1087
0.040982
2.3142622
1008
0.052023
2.8019963
890
0.12154
3.4645009
887
0.033112
3.4645009
887
0.033112
Observations:
With higher-order modes, absolute error is higher in order of ascending frequency
regardless of normal deviation faceting applied
This is expected due to some solution dependence on ‘starting’ frequency.
Added adaptive elements are ‘shared’ among modes. Yet higher order
modes have more ‘focused’ field peaks as compared to more fundamental
modes. Therefore more rapid improvement for lower order modes are an
artifact of the adaptation technique and not one volume correction can
strongly influence.
Note that for higher-accuracy analysis of the higher frequency modes, the
solution can be executed with solution settings that will find that as the
lowest frequency mode.
Even 22.5 degree setting will result in better than 0.05% error for the
fundamental mode solution.
40 and 45 degree cases had identical meshes and results
When used to ‘reduce’ mesh, other quality checks may still constrain the
result to more than just the surface approximation settings requested.
Conclusions:
For simple canonical shapes and fundamental modes, increased faceting is
unnecessary unless extremely tight accuracy deviations are required
Ansoft High Frequency Structure Simulator v10 User’s Guide
4.1-11
4.1
Mesh Operations
Source:
K. K. So and K. W. Leung, “Annular Slot Excited Dielectric Resonator Antenna
with a Backing Cavity,” Proceedings of the 2002 IEEE Antennas and Propagation
Society International Symposium, San Antonio, TX, June 2002, Volume 4
Description:
A hemispherical dielectric resonator antenna (DRA) is fed by a coaxial cable
across an annular ring slot, which couples the DRA to a hemispherical cavity
beneath it. This project has a combination of spherical and planar-circle curves
which should give good evidence of the utility of the volume correction approach.
The source provides both author-derived analytical results and measurement
results.
Benchmark:
An image of the modeled geometry is shown (below, right).
Symmetry was used (1 plane).
Cavity (vacuum filled) is 25mm radius; DRA is 12.5 mm radius.
DRA material has εr = 9.5
Annular ring outer radius is 5.8 mm, 1 mm width
Feed is generated using a lumped gap source port spanning the annular
ring (see detail image)
A 30mm radius by 35mm height polyhedron (16 sides) is used for the
radiation boundary.
Bottom ground plane is treated as
‘infinite ground’ boundary condition
Feed Detail
Solution requested using only default surface approximations
10 adaptive passes or to delta-S of 0.01 at adaptive frequency of
3.75 GHz
2.5 – 5 GHz fast sweep requested
Ansoft High Frequency Structure Simulator v10 User’s Guide
4.1-12
4.1
Mesh Operations
Results:
Plots of S11 vs. frequency and real and imaginary Z11 vs. frequency are shown
Results conformed almost exactly to source’s reported measured results, and
were closer to measurements than source analysis
HFSS v8.5 solved to effectively the same result, but required about 4 times the
mesh
3324 at pass 8 (v10) vs. 13,300 tetrahedra at pass 11 (v8.5)
Conclusions:
This provides an example of a project for which the volume perturbation is
extremely well-suited, by providing the proper dielectric resonance volume
Past experiments with as many as 24 facets per circumference without
volume perturbation demonstrated a noticable frequency error, therefore
the role of the new solution capability in this success is clear.
Solution accuracy was excellent in absolute terms even with default settings, and
greatly exceeded HFSS v8.5’s capabilities
A second simulation with Normal Deviation set to 15 degrees solved to the
same results and excellent convergence, still beating the HFSS v8.5 mesh
required
Ansoft High Frequency Structure Simulator v10 User’s Guide
4.1-13
4.1
Mesh Operations
Source:
http://www.jlab.org/~piller/spoke/spoke.htm
Description:
A Spoke cavity is used in accelerators for ion beams. This variant is a ‘low Beta’
type. The cavity consists of a cylindrical volume with spherical sections
subtracted from the flat ends. The ‘spoke’ is a smaller cylinder with its axis
orthogonal to the main cavity’s axis that cuts through the cavity centerline on a
diameter. There is an input/output beam pipe that runs coaxial with the main
cavity and exits the two concave spheroid ends. Due to symmetry these cavities
are usually analyzed in 1/8 sections with PHC boundary conditions
Benchmark:
An image of the modeled cavity geometry from the HFSS graphical interface is
shown (below, right).
Main cavity 21.908 cm radius by 25.4cm height
Spherical subtractions have radius 64.572 cm
Spoke is 3.81 cm radius; beam pipe 1.359 cm radius
Solved for Normal Deviations from 5 to 30 degrees (as parametric sweep)
Solution settings 10 passes or to delta-f of 0.01%(real)
The beam ports were left as PHC bondaries, so port loading is not
included in these simulation results
Results:
A plot of solved resonant frequency vs. the Normal Deviation surface
approximation setting used is shown above left. Tabulated results are on the
page following, with mesh and error statistics
The reference website indicates that a different solution method for the cavity
obtained a resonance frequency of 338.048 MHz, yet the measurement obtained
348.578 MHz. Deltas to both are shown in the table.
Ansoft High Frequency Structure Simulator v10 User’s Guide
4.1-14
4.1
Mesh Operations
Results, cont.
Normal
Deviation f_r (MHz)
(deg)
5 339.332
10 341.486
15 344.907
20 347.903
25 347.353
30 352.195
Final Delta-f
Delta vs.
Delta vs. Ref.
Final
Ref.
Measurement Tetrahedra Convergence
Count
(%)
Analysis (%)
(%)
0.379827717
2.652490978
21160
0.0021053
1.017015335
2.034551808
9425
0.011095
2.029001799
1.053135884
4246
0.10175
2.915266471
0.19364389
3356
0.1472
2.752567683
0.351427801
3757
0.016916
4.184908652
1.037644372
2601
0.3341
Observations:
Since the reference analysis and measurement do not match, neither can be
taken as an absolute accuracy validator for comparison to the HFSS results.
The measurement was of a cavity with port loading at the beam pipe(s) and
a probe loop which will themselves perturb results slightly
The trend of resonant frequency shift with tighter normal deviation restriction is
quite nearly linear
Tighter initial faceting results in better reported convergence for the same pass
count
V8.5 convergence was still not at low levels after the last solved pass. Therefore
it was only coincidentally near the most-refined HFSS v10 solution. Carrying the
HFSS v8.5 solution to good convergence rather than a limited number of
tetrahedra took more mesh than reported for HFSS v10.
Conclusions:
None of the meshes resulted in inadequate volume filling or clearly incorrect
solutions. This is a geometry type for which increased faceting merely fine-tunes
the resulting convergence and final solution outputs.
Ansoft High Frequency Structure Simulator v10 User’s Guide
4.1-15
4.1
Mesh Operations
Source:
Henry Z. Zhang, “A Wideband Orthogonal-Mode Junction using Ridged Sectoral
Waveguides,” Proceedings of the 2002 IEEE Antennas and Propagation Society
International Symposium, San Antonio, TX, June 2002, Volume 4
Description:
This quadrature orthomode junction (OMJ) uses a tapered septum to convert a
circular, coaxial, quad-ridge waveguide into four contoured ridge waveguides which
have modes analagous to rectangular single-ridge waveguide. The use of tapered
septums intersecting with circular cross-sections necessitates drawing in true
curvature.
Benchmark:
The geometry is shown above. Dimensions are as follows:
Outer radius 160 mm, Ridge diameter 150mm, center diameter 60mm
Ridges subtend 45 degrees, evenly spaced at 90 degree intervals
Septums subtend 2 degrees and extend half the length of the modeled section
(400mm)
Two small ‘perturbers’ of εr = 1.001 (in red) are inserted at the singlewaveguide end to provide stabilization of the degenerate mode order
The HFSS v10 project was generated by direct translation of the v8.5 project, and
solved mesh surface approximation settings.
900 MHz adapt, swept from 400 – 950 MHz
10 passes or to a Delta-S of 0.009
10 and 15 degree normal deviation allowance
Ansoft High Frequency Structure Simulator v10 User’s Guide
4.1-16
4.1
Mesh Operations
Results
Solution results are shown below, focusing on return loss.
Results for 15 degree normal deviation are still unstable
Delta-S of 0.0342; final mesh of 16,177 tetrahedra
Results for 10 degree normal deviation are excellent
Delta-S of 0.00752; final mesh of 15,897 tetrahedra (shown)
Conclusions:
Due to very narrow annular gaps at the ridge peaks, this geometry type is poorly
meshed without user-guidance in the form of tighter surface approximation
settings, providing an example for which such guidance is required
However, with 10 degree faceting the solution convergence was better and to a
smaller final mesh than with 15 degree faceting. Therefore in geometric cases
where surface approximations are required for a good answer, they do not
necessarily imply a longer solution time.
Ansoft High Frequency Structure Simulator v10 User’s Guide
4.1-17
Examples - Contents
Chapter 5.0 – Antenna Examples
5.1 – UHF Probe
5.2 – Circular Waveguide Horn
5.3 – Probe Feed Patch
5.4 – Slot Coupled Patch
5.5 – Specific Absorption Rate
5.6 – CPW Feed Bowtie Antenna
5.7 – Endfire Array
Chapter 6.0 – Microwave Examples
6.1 – Magic T
6.2 – Coax Bend
6.3 – Ring Hybrid
6.4 – Coax Stub
Includes Optimetrics Example
6.5 – Microstrip - Wave Ports
Includes Optimetrics Example
6.6 – Dielectric Resonator
Chapter 7.0 – Filter Examples
7.1 – Bandpass Filter
7.2 – Bandstop Filter
Chapter 8.0 – Signal Integrity Examples
8.1 – LVDS Differential Pair
Includes Optimetrics Example
8.1a – LVDS Differential Pair Transient Simulation (Ansoft Designer)
8.2 – Segmented Return Path
8.2a – Segmented Return Path TDR (Ansoft Designer)
8.3 – Non-Ideal Planes
8.4 – Return Path
Chapter 9.0 – EMC/EMI Examples
9.1 – Heat Sink
9.2 - Enclosure
Chapter 10.0 – On Chip Component Examples
10.1 – Spiral Inductor
Ansoft High Frequency Structure Simulator v10 User’s Guide
Chapter 5.0
Chapter 5.0 – Antenna Examples
5.1 – UHF Probe
5.2 – Circular Waveguide Horn
5.3 – Probe Feed Patch
5.4 – Slot Coupled Patch
5.5 – Specific Absorption Rate
5.6 – CPW Feed Bowtie Antenna
5.7 – Endfire Array
Ansoft High Frequency Structure Simulator v10 User’s Guide
1
5.1
Example – UHF Probe
The Ultra-High Frequency (UHF) Probe
This example is intended to show you how to create, simulate, and analyze a
UHF probe, using the Ansoft HFSS Design Environment.
Ansoft High Frequency Structure Simulator v10 User’s Guide
5.1-1
5.1
Example – UHF Probe
Ansoft HFSS Design Environment
The following features of the Ansoft HFSS Design Environment are used to
create this passive device model
3D Solid Modeling
Primitives: Cylinders, Boxes
Boolean Operations: Unite, Subtract
Boundaries/Excitations
Ports: Wave Ports
Analysis
Sweep:: Fast Frequency
Results
Cartesian plotting
Field Overlays:
3D Far Field Plots
Ansoft High Frequency Structure Simulator v10 User’s Guide
5.1-2
5.1
Example – UHF Probe
Getting Started
Launching Ansoft HFSS
1.
To access Ansoft HFSS, click the Microsoft Start button, select Programs,
Programs and select
the Ansoft, HFSS 10 program group. Click HFSS 10.
10
Setting Tool Options
To set the tool options:
Note: In order to follow the steps outlined in this example, verify that the
following tool options are set :
1. Select the menu item Tools > Options > HFSS Options
2. HFSS Options Window:
1. Click the General tab
Use Wizards for data entry when creating new boundaries:: Checked
Duplicate boundaries with geometry:: Checked
2. Click the OK button
3. Select the menu item Tools > Options > 3D Modeler Options.
Options
4. 3D Modeler Options Window:
1. Click the Operation tab
Automatically cover closed polylines:: Checked
2. Click the Drawing tab
Edit property of new primitives:: Checked
3. Click the OK button
Ansoft High Frequency Structure Simulator v10 User’s Guide
5.1-3
5.1
Example – UHF Probe
Opening a New Project
To open a new project:
1. In an Ansoft HFSS window, click the On the Standard toolbar, or
select the menu item File > New.
2. From the Project menu, select Insert HFSS Design.
Set Solution Type
To set the solution type:
1. Select the menu item HFSS > Solution Type
2. Solution Type Window:
1. Choose Driven Terminal
2. Click the OK button
Ansoft High Frequency Structure Simulator v10 User’s Guide
5.1-4
5.1
Example – UHF Probe
Creating the 3D Model
Set Model Units
To set the units:
1. Select the menu item 3D Modeler > Units
2. Set Model Units:
1. Select Units: in (inches)
2. Click the OK button
Set Default Material
To set the default material:
1. Using the 3D Modeler Materials toolbar, choose Select
2. Select Definition Window:
1. Type copper in the Search by Name field
2. Click the OK button
Ansoft High Frequency Structure Simulator v10 User’s Guide
5.1-5
5.1
Example – UHF Probe
Creating Annular Rings
Creating a ring is accomplished by creating a cylinder that represents the outer
radius and a cylinder that represents the inner radius. By performing a Boolean
subtraction, the resulting geometry is a ring.
For this model, two sets of rings are necessary. Instead of manually creating
both rings, we will create one ring, copy it, and edit the dimensions of the copy.
Create Ring 1
1. Select the menu item Draw > Cylinder
2. Using the coordinate entry fields, enter the cylinder position
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the radius:
dX: 0.31,
0.31 dY: 0.0,
0.0 dZ: 0.0, Press the Enter key
4. Using the coordinate entry fields, enter the height:
dX: 0.0,
0.0 dY: 0.0,
0.0 dZ: 5.0, Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: ring_inner
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View. Or press the CTRL+D
key
Ansoft High Frequency Structure Simulator v10 User’s Guide
5.1-6
5.1
Example – UHF Probe
Creating Annular Rings (Continued)
Create Ring 1 (Continued)
1. Select the menu item Draw > Cylinder
2. Using the coordinate entry fields, enter the cylinder position
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the radius:
dX: 0.37,
0.37 dY: 0.0,
0.0 dZ: 0.0,
0.0 Press the Enter key
4. Using the coordinate entry fields, enter the height:
dX: 0.0,
0.0 dY: 0.0,
0.0 dZ: 5.0,
5.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: ring_1
3. Click the OK button
To select objects to be subtracted:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: ring_1, ring_inner
2. Click the OK button
To subtract:
1. Select the menu item 3D Modeler > Boolean > Subtract
2. Subtract Window
Blank Parts: ring_1
Tool Parts: ring_inner
Clone tool objects before subtract: Unchecked
Click the OK button
Ansoft High Frequency Structure Simulator v10 User’s Guide
5.1-7
5.1
Example – UHF Probe
Creating Annular Rings (Continued)
Create Ring 2
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: ring_1
2. Click the OK button
3. Select the menu item Edit > Copy
4. Select the menu item Edit > Paste
Change the dimensions of Ring 2
1. To change the dimensions of ring_2, expand the model tree as shown
below. It should be noted that order of the editing is important. If you make
the inner radius > then the outer radius, a invalid object will result and it will
be removed from the model.
2. Using the mouse, double click the left mouse button on the CreateCylinder
command for ring_2
3.
Properties dialog
1. Change the radius to: 0.5 in
2. Click the OK button
4. Using the mouse, double click the left mouse button on the CreateCylinder
command for ring_inner1
5.
Properties dialog
1. Change the radius to: 0.435 in
2. Click the OK button
Ansoft High Frequency Structure Simulator v10 User’s Guide
5.1-8
5.1
Example – UHF Probe
Create Arm_1
To create Arm_1
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: -0.1,
0.1 Y: -0.31,
0.31 Z: 5.0,
5.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the base
rectangle:
dX: 0.2,
0.2 dY: -4.69,
4.69 dZ: -0.065,
0.065 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Arm_1
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Group Conductors
To group the conductors:
1. Select the menu item Edit > Select All Visible. Or press the CTRL+A key
2. Select the menu item, 3D Modeler > Boolean > Unite
Ansoft High Frequency Structure Simulator v10 User’s Guide
5.1-9
5.1
Example – UHF Probe
Create the Center pin
To create the center pin
1. Select the menu item Draw > Cylinder
2. Using the coordinate entry fields, enter the cylinder position
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the radius:
dX: 0.1,
0.1 dY: 0.0,
0.0 dZ: 0.0,
0.0 Press the Enter key
4. Using the coordinate entry fields, enter the height:
dX: 0.0,
0.0 dY: 0.0,
0.0 dZ: 5.1,
5.1 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: center_pin
3. Click the OK button
Ansoft High Frequency Structure Simulator v10 User’s Guide
5.1-10
5.1
Example – UHF Probe
Create Arm_2
To create Arm_2
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: -0.1,
0.1 Y: 0.0,
0.0 Z: 5.1,
5.1 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the base
rectangle:
dX: 0.2,
0.2 dY: 5.0,
5.0 dZ: -0.065,
0.065 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Arm_2
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
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5.1
Example – UHF Probe
Create the Grounding Pin
To create the grounding pin
1. Select the menu item Draw > Cylinder
2. Using the coordinate entry fields, enter the cylinder position
X: 0.0,
0.0 Y: 1.0,
1.0 Z: 0.0, Press the Enter key
3. Using the coordinate entry fields, enter the radius:
dX: 0.0625,
0.0625 dY: 0.0,
0.0 dZ: 0.0,
0.0 Press the Enter key
4. Using the coordinate entry fields, enter the height:
dX: 0.0,
0.0 dY: 0.0,
0.0 dZ: 5.1,
5.1 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: pin
3. Click the OK button
Group Conductors
To group the conductors:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Arm_2, center_pin,
center_pin, pin
Note: Use the Ctrl + Left mouse button to select multiple
objects
2. Click the OK button
3. Select the menu item, 3D Modeler > Boolean > Unite
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5.1
Example – UHF Probe
Create the Wave port
To create a circle that represents the port:
1. Select the menu item Draw > Circle
2. Using the coordinate entry fields, enter the center position
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the radius of the circle:
dX: 0.31,
0.31 dY: 0.0,
0.0 dZ: 0.0,
0.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: p1
3. Click the OK button
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5.1
Example – UHF Probe
Set Default Material
To set the default material:
Using the 3D Modeler Materials toolbar, choose vacuum
Create Air
To create Air
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: -5.0,
5.0 Y: -10.0,
10.0 Z: 0.0, Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the base
rectangle:
dX: 10.0,
10.0 dY: 20.0,
20.0 dZ: 12.0,
12.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Air
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Create Radiation Boundary
To create a radiation boundary
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Air
2. Click the OK button
3. Select the menu item HFSS > Boundaries >Assign> Radiation
4. Radiation Boundary window
1. Name: Rad1
2. Click the OK button
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5.1
Example – UHF Probe
Create Wave Port Excitation 1 (Continued)
To select the object p1:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: p1
2. Click the OK button
To assign wave port excitation
1. Select the menu item HFSS > Excitations > Assign > Wave Port
2. Wave Port : General
1. Name: p1,
p1
2. Click the Next button
3. Wave Port : Terminals
1. Number of Terminals: 1,
2. For T1,
T1 click the Undefined column and select New Line
3. Using the coordinate entry fields, enter the vector position
X: 0.31, Y: 0.0, Z: 0.0, Press the Enter key
4. Using the coordinate entry fields, enter the vertex
dX:
dX: -0.21, dY:
dY: 0.0, dZ:
dZ: 0.0, Press the Enter key
5. Click the Next button
4. Wave Port : Differential Pairs
1. Click the Next button
5. Wave Port : Post Processing
1. Reference Impedance: 50
6. Click the Finish button
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5.1
Example – UHF Probe
Create Infinite Ground Plane
To create an Infinite ground
1. Select the menu item Edit > Select > Faces
2. Graphically select the face of the Air object at Z=0
3. Select the menu item HFSS > Boundaries > Assign> Finite Conductivity
4. Finite Conductivity Boundary window
1. Name: gnd_plane
2. Use Material: Checked
3. Click the vacuum button
4. Select Definition Window:
1. Type copper in the Search
by Name field
2. Click the OK button
5. Infinite Ground Plane: Checked
6. Click the OK button
Create a Radiation Setup
To define the radiation setup
1. Select the menu item HFSS > Radiation > Insert Far Field Setup > Infinite
Sphere
2.
Far Field Radiation Sphere Setup dialog
1. Infinite Sphere Tab
1. Name: ff_2d
2. Phi: (Start: 0, Stop: 90, Step Size: 90)
3. Theta: (Start: -180, Stop: 180, Step Size: 2)
2. Click the OK button
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5.1
Example – UHF Probe
Analysis Setup
Creating an Analysis Setup
To create an analysis setup:
1. Select the menu item HFSS > Analysis Setup > Add Solution Setup
2. Solution Setup Window:
1. Click the General tab::
Solution Frequency:: 0.55 GHz
Maximum Number of Passes: 10
Maximum Delta S per Pass: 0.02
2. Click the OK button
Adding a Frequency Sweep
To add a frequency sweep:
1. Select the menu item HFSS > Analysis Setup > Add Sweep
1. Select Solution Setup: Setup1
2. Click the OK button
2. Edit Sweep Window:
1. Sweep Type:: Fast
2. Frequency Setup Type:: Linear Count
Start: 0.35GHz
Stop:: 0.75GHz
Count:: 401
Save Fields: Checked
3. Click the OK button
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5.1
Example – UHF Probe
Save Project
To save the project:
1. In an Ansoft HFSS window, select the menu item File > Save As.
2. From the Save As window, type the Filename: hfss_uhf_probe
3. Click the Save button
Analyze
Model Validation
To validate the model:
1. Select the menu item HFSS > Validation Check
2. Click the Close button
Note: To view any errors or warning messages, use the Message
Manager.
Analyze
To start the solution process:
1. Select the menu item HFSS > Analyze All
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5.1
Example – UHF Probe
Solution Data
To view the Solution Data:
1. Select the menu item HFSS > Results > Solution Data
To view the Profile:
1. Click the Profile Tab.
To view the Convergence:
1. Click the Convergence Tab
Note: The default view is for convergence is Table.
Table Select
the Plot radio button to view a graphical representations of
the convergence data.
To view the Matrix Data:
1. Click the Matrix Data Tab
Note: To view a real-time update of the Matrix Data, set the
Simulation to Setup1, Last Adaptive
2. Click the Close button
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5.1
Example – UHF Probe
Create Reports
Create Terminal SS-Parameter Plot - Magnitude
To create a report:
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Terminal S Parameters
2. Display Type: Rectangular
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: Sweep1
2. Domain: Sweep
3. Click the Y tab
1. Category: Terminal S Parameter
2. Quantity: St(p1,p1),
3. Function: dB
4. Click the Add Trace button
4. Click the Done button
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5.1
Example – UHF Probe
Far Field Overlays
Create Far Field Overlay
To create a 2D polar far field plot :
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Far Fields
2. Display Type: Radiation Pattern
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: LastAdaptive
2. Geometry: ff_2d
3. In the Sweeps tab, select Phi under the Name column, and on the
drop list, select Theta.
Theta This changes the primary sweep to Theta.
4. In the Mag tab
1. Category: Gain
2. Quantity: GainTotal
3. Function: dB
4. Click the Add Trace button
5. Click the Done button
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5.2
Example – Conical Horn
Dual Mode Conical Horn
This example is intended to show you how to create, simulate, and analyze a
waveguide horn antenna using the Ansoft HFSS Design Environment.
Ansoft High Frequency Structure Simulator v10 User’s Guide
5.2-1
5.2
Example – Conical Horn
Ansoft HFSS Design Environment
The following features of the Ansoft HFSS Design Environment are used to
create this passive device model:
3D Solid Modeling
Primitives: Cylinders
Boolean: Union, Subtract, Connect
Boundaries/Excitations
Excitations: Wave Ports
Boundaries: Radiation
Results
Plotting: Radiation Pattern
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5.2
Example – Conical Horn
Design Review
Port Size/Type
Since the port is external to the model we could use a Wave Port. The
size of the port is determined by the physical dimensions of the
waveguide. Because the waveguide is circular, we must Polarize the EField for the port definition.
Free Space
Since we are evaluating a radiating structure, we need to create a free
space environment for the device to operate in. This can be achieved by
using the Radiation Boundary condition or a Perfectly Matched Layer
(PML). We will use a Radiation Boundary since the surface will be
cylindrical.
The Radiation Boundary needs to be placed at least λ/4 from radiating
devices. For our example we will assume that ~λ/4 (0.6in)
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5.2
Example – Conical Horn
Getting Started
Launching Ansoft HFSS
1.
To access Ansoft HFSS, click the Microsoft Start button, select Programs,
Programs and select
the Ansoft, HFSS 10 program group. Click HFSS 10.
10
Setting Tool Options
To set the tool options:
Note: In order to follow the steps outlined in this example, verify that the
following tool options are set :
1. Select the menu item Tools > Options > HFSS Options
2. HFSS Options Window:
1. Click the General tab
Use Wizards for data entry when creating new boundaries:: Checked
Duplicate boundaries with geometry:: Checked
2. Click the OK button
3. Select the menu item Tools > Options > 3D Modeler Options.
Options
4. 3D Modeler Options Window:
1. Click the Operation tab
Automatically cover closed polylines:: Checked
2. Click the Drawing tab
Edit property of new primitives:: Checked
3. Click the OK button
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5.2
Example – Conical Horn
Opening a New Project
To open a new project:
1. In an Ansoft HFSS window, click the On the Standard toolbar, or
select the menu item File > New.
2. From the Project menu, select Insert HFSS Design.
Set Solution Type
To set the solution type:
1. Select the menu item HFSS > Solution Type
2. Solution Type Window:
1. Choose Driven Modal
2. Click the OK button
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5.2
Example – Conical Horn
Creating the 3D Model
Set Model Units
To set the units:
1. Select the menu item 3D Modeler > Units
2. Set Model Units:
1. Select Units: in
2. Click the OK button
Set Default Material
To set the default material:
Using the 3D Modeler Materials toolbar, choose vacuum
Create Circular Waveguide
Create waveguide
1. Select the menu item Draw > Cylinder
2. Using the coordinate entry fields, enter the cylinder position
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0 Press the Enter key
3. Using the coordinate entry fields, enter the radius:
dX: 0.838,
0.838 dY: 0.0,
0.0 dZ: 0.0 Press the Enter key
4. Using the coordinate entry fields, enter the height:
dX: 0.0,
0.0 dY: 0.0,
0.0 dZ: 3.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Waveguide
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Or press the CTRL+D key
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5.2
Example – Conical Horn
Create Offset Coordinate System
Create CS
1. Select the menu item 3D Modeler > Coordinate System > Create > Relative
CS > Offset
2.
Using the coordinate entry fields, enter the origin
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 3.0 Press the Enter key
Create Transition Region
Create waveguide transition
1. Select the menu item Draw > Cone
2. Using the coordinate entry fields, enter the center position
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0 Press the Enter key
3. Using the coordinate entry fields, enter the lower radius:
dX: 0.838,
0.838 dY: 0.0,
0.0 dZ: 0.0 Press the Enter key
4. Using the coordinate entry fields, enter the upper radius:
dX: 0.709,
0.709 dY: 0.0,
0.0 dZ: 0.0 Press the Enter key
5. Using the coordinate entry fields, enter the height:
dX: 0.0,
0.0 dY: 0.0,
0.0 dZ: 1.227 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Taper
3. Click the OK button
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5.2
Example – Conical Horn
Create Offset Coordinate System
Create CS
1. Select the menu item 3D Modeler > Coordinate System > Create >
Relative CS > Offset
2.
Using the coordinate entry fields, enter the origin
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 1.227 Press the Enter key
Create the Throat
Create Throat
1. Select the menu item Draw > Cylinder
2. Using the coordinate entry fields, enter the cylinder position
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0 Press the Enter key
3. Using the coordinate entry fields, enter the radius:
dX: 1.547,
1.547 dY: 0.0,
0.0 dZ: 0.0 Press the Enter key
4. Using the coordinate entry fields, enter the height:
dX: 0.0,
0.0 dY: 0.0,
0.0 dZ: 3.236 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Throat
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
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5.2
Example – Conical Horn
Group Object
To group the objects:
1. Select the menu item Edit > Select All Visible. Or press the CTRL+A key
2. Select the menu item, 3D Modeler > Boolean > Unite
Rename group
To rename the group of objects:
1. From the Model tree, select the only object shown
2. Click the Properties button
1. For the Value of Name type: Horn_Air
2. Click the OK button
3. Click the Done button
Set Working Coordinate System
To set the working coordinate system:
1. Select the menu item 3D Modeler > Coordinate System > Set Working CS
2. Select Coordinate System Window,
1. From the list, select the CS: Global
2. Click the Select button
Set Default Material
To set the default material:
1. Using the 3D Modeler Materials toolbar, choose Select
2. Select Definition Window:
1. Type pec in the Search by Name field
2. Click the OK button
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5.2
Example – Conical Horn
Create the Horn Wall
Create horn
1. Select the menu item Draw > Cylinder
2. Using the coordinate entry fields, enter the cylinder position
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0 Press the Enter key
3. Using the coordinate entry fields, enter the radius:
dX: 1.647,
1.647 dY: 0.0,
0.0 dZ:: 0.0 Press the Enter key
4. Using the coordinate entry fields, enter the height:
dX:: 0.0,
0.0 dY:: 0.0,
0.0 dZ:: 7.463 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Horn
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Complete the Horn
To select the object
Select the menu item Edit > Select All Visible. Or press the CTRL+A key
To complete the horn:
1. Select the menu item 3D Modeler > Boolean > Subtract
2. Subtract Window
Blank Parts: Horn
Tool Parts: Horn_Air
Clone tool objects before subtract: Unchecked
Click the OK button
Ansoft High Frequency Structure Simulator v10 User’s Guide
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5.2
Example – Conical Horn
Set Default Material
To set the default material:
Using the 3D Modeler Materials toolbar, choose vacuum
Create Air
Create Air
1. Select the menu item Draw > Cylinder
2. Using the coordinate entry fields, enter the cylinder position
X: 0.0,
0.0 Y: 0.0,
0.0 Z:: 0.0 Press the Enter key
3. Using the coordinate entry fields, enter the radius:
dX:: 2.2,
2.2 dY:: 0.0,
0.0 dZ:: 0.0 Press the Enter key
4. Using the coordinate entry fields, enter the height:
dX:: 0.0,
0.0 dY:: 0.0,
0.0 dZ:: 8.2 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Air
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Create Radiation Boundary
To create a radiation boundary
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Air
2. Click the OK button
3. Select the menu item HFSS > Boundaries > Assign> Radiation
4. Radiation Boundary window
1. Name: Rad1
2. Click the OK button
Ansoft High Frequency Structure Simulator v10 User’s Guide
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5.2
Example – Conical Horn
Create the Wave port
To create a circle that represents the port:
1. Select the menu item Draw > Circle
2. Using the coordinate entry fields, enter the center position
X:: 0.0,
0.0 Y:: 0.0,
0.0 Z:: 0.0 Press the Enter key
3. Using the coordinate entry fields, enter the radius of the circle:
dX:: 0.838,
0.838 dY:: 0.0,
0.0 dZ:: 0.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: p1
3. Click the OK button
To select the object p1:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: p1
2. Click the OK button
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5.2
Example – Conical Horn
Create Wave Port Excitation 1 (Continued)
To assign wave port excitation
1. Select the menu item HFSS > Excitations > Assign > Wave Port
2. Wave Port : General
1. Name: p1
2. Click the Next button
3. Wave Port : Modes
1. Number of Modes: 2
2. For Mode 1,
1 click the None column and select New Line
3. Using the coordinate entry fields, enter the vector position
X:: -0.838,
0.838 Y:: 0.0,
0.0 Z:: 0.0 Press the Enter key
4. Using the coordinate entry fields, enter the vertex
dX:: 1.676,
1.676 dY:: 0.0,
0.0 dZ:: 0.0 Press the Enter key
5. Polarize E Field: Checked
6. Click the Next button
4. Wave Port : Post Processing
5. Click the Finish button
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5.2
Example – Conical Horn
Create Offset Coordinate System
Create CS
1. Select the menu item 3D Modeler > Coordinate System > Create >
Relative CS > Offset
2.
Using the coordinate entry fields, enter the origin
X:: 0.0,
0.0 Y:: 0.0,
0.0 Z:: 7.463 Press the Enter key
Create a Radiation Setup
To define the radiation setup
1. Select the menu item HFSS > Radiation > Insert Far Field Setup > Infinite
Sphere
2.
Far Field Radiation Sphere Setup dialog
Infinite Sphere Tab
1. Name: ff_2d
2. Phi: (Start: 0, Stop: 90, Step Size: 90)
3. Theta: (Start: -180, Stop: 180, Step Size: 2)
1. Coordinate System Tab
1. Select Use local coordinate system
2. Choose RelativeCS3
2. Click the OK button
Ansoft High Frequency Structure Simulator v10 User’s Guide
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5.2
Example – Conical Horn
Analysis Setup
Creating an Analysis Setup
To create an analysis setup:
1. Select the menu item HFSS > Analysis Setup > Add Solution Setup
2. Solution Setup Window:
1. Click the General tab::
Solution Frequency:: 5.0 GHz
Maximum Number of Passes: 10
Maximum Delta S per Pass: 0.02
2. Click the OK button
Save Project
To save the project:
1. In an Ansoft HFSS window, select the menu item File > Save As.
2. From the Save As window, type the Filename: hfss_chorn
3. Click the Save button
Analyze
Model Validation
To validate the model:
1. Select the menu item HFSS > Validation Check
2. Click the Close button
Note: To view any errors or warning messages, use the Message
Manager.
Analyze
To start the solution process:
1. Select the menu item HFSS > Analyze All
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5.2
Example – Conical Horn
Solution Data
To view the Solution Data:
1. Select the menu item HFSS > Results > Solution Data
To view the Profile:
1. Click the Profile Tab.
To view the Convergence:
1. Click the Convergence Tab
Note: The default view is for convergence is Table.
Table Select
the Plot radio button to view a graphical representations of
the convergence data.
To view the Matrix Data:
1. Click the Matrix Data Tab
Note: To view a real-time update of the Matrix Data, set the
Simulation to Setup1, Last Adaptive
2. Click the Close button
Ansoft High Frequency Structure Simulator v10 User’s Guide
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5.2
Example – Conical Horn
Far Field Overlays
Edit Sources
To Modify a Terminal excitation:
1. Select the menu item HFSS > Fields > Edit Sources
2. Edit Sources window
1. Source: p1:m1
1. Scaling Factor: 1
2. Offset: 0
2. Source: p1:m2
1. Scaling Factor: 1
2. OffsetPhase: 90
3. Click the OK button
Create Far Field Overlay
To create a 2D polar far field plot :
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Far Fields
2. Display Type: Radiation Pattern
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: LastAdaptive
2. Geometry: ff_2d
3. In the Sweeps tab
1. Primary Sweep: Click on the Name Phi and toggle to Theta
4. In the Mag tab
1. Category: Gain
2. Quantity: GainLHCP,
GainLHCP, GainRHCP
3. Function: dB
5. Click the Done button
Ansoft High Frequency Structure Simulator v10 User’s Guide
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5.2
Example – Conical Horn
Ansoft High Frequency Structure Simulator v10 User’s Guide
5.2-18
5.3
Example – Probe Feed Patch Antenna
The Probe Feed Patch Antenna
This example is intended to show you how to create, simulate, and analyze a
probe feed patch antenna using the Ansoft HFSS Design Environment.
Patch (Signal)
Sub1 (Dielectric)
0.32cm
Infinite Ground
Ansoft High Frequency Structure Simulator v10 User’s Guide
5.3-1
5.3
Example – Probe Feed Patch Antenna
Getting Started
Launching Ansoft HFSS
1.
To access Ansoft HFSS, click the Microsoft Start button, select Programs,
Programs and select
the Ansoft > HFSS 10 program group. Click HFSS 10.
10
Setting Tool Options
To set the tool options:
Note: In order to follow the steps outlined in this example, verify that the
following tool options are set :
1. Select the menu item Tools > Options > HFSS Options
2. HFSS Options Window:
1. Click the General tab
Use Wizards for data entry when creating new boundaries:: Checked
Duplicate boundaries with geometry:: Checked
2. Click the OK button
3. Select the menu item Tools > Options > 3D Modeler Options.
Options
4. 3D Modeler Options Window:
1. Click the Operation tab
Automatically cover closed polylines:: Checked
2. Click the Drawing tab
Edit property of new primitives:: Checked
3. Click the OK button
Ansoft High Frequency Structure Simulator v10 User’s Guide
5.3-2
5.3
Example – Probe Feed Patch Antenna
Opening a New Project
To open a new project:
1. In an Ansoft HFSS window, click the On the Standard toolbar, or
select the menu item File > New.
2. From the Project menu, select Insert HFSS Design.
Set Solution Type
To set the solution type:
1. Select the menu item HFSS > Solution Type
2. Solution Type Window:
1. Choose Driven Terminal
2. Click the OK button
Ansoft High Frequency Structure Simulator v10 User’s Guide
5.3-3
5.3
Example – Probe Feed Patch Antenna
Creating the 3D Model
Set Model Units
To set the units:
1. Select the menu item 3D Modeler > Units
2. Set Model Units:
1. Select Units: cm
2. Click the OK button
Set Default Material
To set the default material:
1. Using the 3D Modeler Materials toolbar, choose Select
2. Select Definition Window:
1. Type Rogers RT/duroid
RT/duroid 5880 (tm) in the Search by Name field
2. Click the OK button
Ansoft High Frequency Structure Simulator v10 User’s Guide
5.3-4
5.3
Example – Probe Feed Patch Antenna
Create Substrate
To create the substrate:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: -5.0,
5.0 Y: -4.5,
4.5 Z: 0.0,
0.0 Press the Enter key
2. Using the coordinate entry fields, enter the opposite corner of the box
dX: 10.0,
10.0 dY: 9.0,
9.0 dZ: 0.32,
0.32 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Sub1
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View. Or press the CTRL+D key
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5.3
Example – Probe Feed Patch Antenna
Create Infinite Ground
To create the infinite ground:
1. Select the menu item Draw > Rectangle
2. Using the coordinate entry fields, enter the rectangle position
X: -5.0,
5.0 Y: -4.5,
4.5 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the rectangle:
dX: 10.0,
10.0 dY: 9.0,
9.0 dZ: 0.0,
0.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Inf_GND
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Assign a Perfect E boundary to the Infinite Ground
To select the trace:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Inf_GND
2. Click the OK button
To assign the Perfect E boundary
1. Select the menu item HFSS > Boundaries > Assign > Perfect E
2. Perfect E Boundary window
1. Name: PerfE_Inf_GND
2. Infinite Ground Plane: Checked
3. Click the OK button
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5.3
Example – Probe Feed Patch Antenna
Create Infinite Ground Cut Out
To create the cut out:
1. Select the menu item Draw > Circle
2. Using the coordinate entry fields, enter the center position
X: -0.5,
0.5 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the radius:
dX: 0.16,
0.16 dY: 0.0,
0.0 dZ: 0.0,
0.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Cut_Out
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View
Complete the Infinite Ground
To select the objects Inf_GND & Cut_Out:
Cut_Out:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Inf_GND,
Inf_GND, Cut_Out
2. Click the OK button
To complete the ring:
1. Select the menu item 3D Modeler > Boolean > Subtract
2. Subtract Window
Blank Parts: Inf_GnD
Tool Parts: Cut_Out
Clone tool objects before subtract: Unchecked
Click the OK button
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5.3
Example – Probe Feed Patch Antenna
Create Patch
To create the patch:
1. Select the menu item Draw > Rectangle
2. Using the coordinate entry fields, enter the rectangle position
X: -2.0,
2.0 Y: -1.5,
1.5 Z: 0.32,
0.32 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the rectangle:
dX: 4.0,
4.0 dY: 3.0,
3.0 dZ: 0.0,
0.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Patch
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Assign a Perfect E boundary to the Trace
To select the trace:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Patch
2. Click the OK button
To assign the Perfect E boundary
1. Select the menu item HFSS > Boundaries > Assign > Perfect E
2. Perfect E Boundary window
1. Name: PerfE_Patch
2. Click the OK button
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5.3
Example – Probe Feed Patch Antenna
Set Default Material
To set the default material:
1. Using the 3D Modeler Materials toolbar, choose vacuum
Create the Coax
To create the coax:
1. Select the menu item Draw > Cylinder
2. Using the coordinate entry fields, enter the cylinder position
X: -0.5,
0.5 Y: 0.0,
0.0 Z: 0.0 Press the Enter key
3. Using the coordinate entry fields, enter the radius:
dX: 0.16,
0.16 dY: 0.0,
0.0 dZ: 0.0 Press the Enter key
4. Using the coordinate entry fields, enter the height:
dX: 0.0,
0.0 dY: 0.0,
0.0 dZ: -0.5 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Coax
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
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5.3
Example – Probe Feed Patch Antenna
Set Default Material
To set the default material:
1. Using the 3D Modeler Materials toolbar, choose Select
2. Select Definition Window:
1. Type pec in the Search by Name field
2. Click the OK button
Create the Coax Pin
To create the coax pin:
1. Select the menu item Draw > Cylinder
2. Using the coordinate entry fields, enter the cylinder position
X: -0.5,
0.5 Y: 0.0,
0.0 Z: 0.0 Press the Enter key
3. Using the coordinate entry fields, enter the radius:
dX: 0.07,
0.07 dY: 0.0,
0.0 dZ: 0.0 Press the Enter key
4. Using the coordinate entry fields, enter the height:
dX: 0.0,
0.0 dY: 0.0,
0.0 dZ: -0.5 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Coax_Pin
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
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5.3
Example – Probe Feed Patch Antenna
Create the Wave port
To create a circle that represents the port:
1. Select the menu item Draw > Circle
2. Using the coordinate entry fields, enter the center position
X:: -0.5,
0.5 Y:: 0.0,
0.0 Z:: -0.5 Press the Enter key
3. Using the coordinate entry fields, enter the radius of the circle:
dX:: 0.16,
0.16 dY:: 0.0,
0.0 dZ:: 0.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Port1
3. Click the OK button
To select the object Port1:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Port1
2. Click the OK button
To assign wave port excitation
1. Select the menu item HFSS > Excitations > Assign > Wave Port
2. Wave Port : General
1. Name: p1
2. Click the Next button
3. Wave Port : Terminals
1. Number of Terminals: 1,
2. For T1,
T1 click the Undefined column and select New Line
3. Using the coordinate entry fields, enter the vector position
X: -0.34,
0.34 Y: 0.0,
0.0 Z: -0.5,
0.5 Press the Enter key
4. Using the coordinate entry fields, enter the vertex
dX: -0.09,
0.09 dY: 0.0,
0.0 dZ: 0.0,
0.0 Press the Enter key
5. Click the Next button
4. Wave Port : Differential Pairs
1. Click the Next button
5. Wave Port : Post Processing
1. Reference Impedance: 50
6. Click the Finish button
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5.3
Example – Probe Feed Patch Antenna
Create the Probe
To create the probe:
1. Select the menu item Draw > Cylinder
2. Using the coordinate entry fields, enter the cylinder position
X: -0.5,
0.5 Y: 0.0,
0.0 Z: 0.0 Press the Enter key
3. Using the coordinate entry fields, enter the radius:
dX: 0.07,
0.07 dY: 0.0,
0.0 dZ: 0.0 Press the Enter key
4. Using the coordinate entry fields, enter the height:
dX: 0.0,
0.0 dY: 0.0,
0.0 dZ: 0.32 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Probe
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
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5.3
Example – Probe Feed Patch Antenna
Set Default Material
To set the default material:
1. Using the 3D Modeler Materials toolbar, choose vacuum
Create Air
To create the air:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: -5.0,
5.0 Y: -4.5,
4.5 Z: 0.0,
0.0 Press the Enter key
2. Using the coordinate entry fields, enter the opposite corner of the box
dX: 10.0,
10.0 dY: 9.0,
9.0 dZ: 3.32,
3.32 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Air
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
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5.3
Example – Probe Feed Patch Antenna
Create Radiation Boundary
Picking the faces:
1. Select the menu item Edit > Select > Faces
2. Graphically select all of the faces of the Air object except the face at Z=0.0cm
To create a radiation boundary
1. Select the menu item HFSS > Boundaries > Assign> Radiation
2. Radiation Boundary window
1. Name: Rad1
2. Click the OK button
Create a Radiation Setup
To define the radiation setup
1. Select the menu item HFSS > Radiation > Insert Far Field Setup > Infinite
Sphere
2.
Far Field Radiation Sphere Setup dialog
1. Select the Infinite Sphere Tab
1. Name: ff_2d
2. Phi: (Start: 0, Stop: 90, Step Size: 90)
3. Theta: (Start: -180, Stop: 180, Step Size: 2)
2. Click the OK button
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5.3
Example – Probe Feed Patch Antenna
Analysis Setup
Creating an Analysis Setup
To create an analysis setup:
1. Select the menu item HFSS > Analysis Setup > Add Solution Setup
2. Solution Setup Window:
1. Click the General tab::
Solution Frequency:: 2.25 GHz
Maximum Number of Passes: 20
Maximum Delta S per Pass: 0.02
2. Click the OK button
Adding a Frequency Sweep
To add a frequency sweep:
1. Select the menu item HFSS > Analysis Setup > Add Sweep
1. Select Solution Setup: Setup1
2. Click the OK button
2. Edit Sweep Window:
1. Sweep Type:: Fast
2. Frequency Setup Type:: Linear Count
Start: 1.0GHz
Stop:: 3.5GHz
Count:: 201
Save Fields: Checked
3. Click the OK button
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5.3
Example – Probe Feed Patch Antenna
Save Project
To save the project:
1. In an Ansoft HFSS window, select the menu item File > Save As.
2. From the Save As window, type the Filename: hfss_probepatch
3. Click the Save button
Analyze
Model Validation
To validate the model:
1. Select the menu item HFSS > Validation Check
2. Click the Close button
Note: To view any errors or warning messages, use the Message
Manager.
Analyze
To start the solution process:
1. Select the menu item HFSS > Analyze All
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5.3
Example – Probe Feed Patch Antenna
Solution Data
To view the Solution Data:
1. Select the menu item HFSS > Results > Solution Data
To view the Profile:
1. Click the Profile Tab.
To view the Convergence:
1. Click the Convergence Tab
Note: The default view is for convergence is Table.
Table Select
the Plot radio button to view a graphical representations of
the convergence data.
To view the Matrix Data:
1. Click the Matrix Data Tab
Note: To view a real-time update of the Matrix Data, set the
Simulation to Setup1, Last Adaptive
2. Click the Close button
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5.3
Example – Probe Feed Patch Antenna
Create Reports
Create Terminal SS-Parameter Plot - Magnitude
To create a report:
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Terminal S Parameters
2. Display Type: Rectangular
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: Sweep1
2. Domain: Sweep
3. Click the Y tab
1. Category: Terminal S Parameter
2. Quantity: St(p1,p1),
3. Function: dB
4. Click the Add Trace button
4. Click the Done button
4. Select the menu Report 2D > Mark All Traces
1. Click the Min button
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5.3
Example – Probe Feed Patch Antenna
Far Field Overlays
Create Far Field Overlay
To create a 2D polar far field plot :
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Far Fields
2. Display Type: Radiation Pattern
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: Sweep1
2. Geometry: ff_2d
3. In the Sweeps tab, select Phi under the Name column, and on the
drop list, select Theta.
Theta This changes the primary sweep to Theta.
4. In the Sweeps tab, select the row labeled Freq and select the
frequency 2.3625 from the list.
5. In the Mag tab
1. Category: Gain
2. Quantity: GainTotal
3. Function: dB
4. Click the Add Trace button
6. Click the Done button
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5.4
Example – Slot Patch
The Slot Coupled Patch Antenna
This example is intended to show you how to create, simulate, and analyze a
probe feed patch antenna using the Ansoft HFSS Design Environment.
Patch (Signal)
Sub1 (Dielectric)
0.16cm
Slot (Plane)
Sub2 (Dielectric)
0.16cm
Feed (Signal)
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5.4
Example – Slot Patch
Getting Started
Launching Ansoft HFSS
1.
To access Ansoft HFSS, click the Microsoft Start button, select Programs,
Programs and select
the Ansoft > HFSS 10 program group. Click HFSS 10
Setting Tool Options
To set the tool options:
Note: In order to follow the steps outlined in this example, verify that the
following tool options are set :
1. Select the menu item Tools > Options > HFSS Options
2. HFSS Options Window:
1. Click the General tab
Use Wizards for data entry when creating new boundaries:: Checked
Duplicate boundaries with geometry:: Checked
2. Click the OK button
3. Select the menu item Tools > Options > 3D Modeler Options.
Options
4. 3D Modeler Options Window:
1. Click the Operation tab
Automatically cover closed polylines:: Checked
2. Click the Drawing tab
Edit property of new primitives:: Checked
3. Click the OK button
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5.4
Example – Slot Patch
Opening a New Project
To open a new project:
1. In an Ansoft HFSS window, click the On the Standard toolbar, or
select the menu item File > New.
2. From the Project menu, select Insert HFSS Design.
Set Solution Type
To set the solution type:
1. Select the menu item HFSS > Solution Type
2. Solution Type Window:
1. Choose Driven Terminal
2. Click the OK button
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Example – Slot Patch
Creating the 3D Model
Set Model Units
To set the units:
1. Select the menu item 3D Modeler > Units
2. Set Model Units:
1. Select Units: cm
2. Click the OK button
Set Default Material
To set the default material:
1. Using the 3D Modeler Materials toolbar, choose Select
2. Select Definition Window:
1. Type Rogers RT/duroid
RT/duroid 5880 (tm) in the Search by Name field
2. Click the OK button
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5.4
Example – Slot Patch
Create Substrate
To create the substrate:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: -7.0,
7.0 Y: -4.5,
4.5 Z: 0.0,
0.0 Press the Enter key
2. Using the coordinate entry fields, enter the opposite corner of the box
dX: 12.0,
12.0 dY: 9.0,
9.0 dZ: 0.32,
0.32 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Sub1
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View. Or press the CTRL+D key
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5.4
Example – Slot Patch
Create the Feed
To create the feed:
1. Select the menu item Draw > Rectangle
2. Using the coordinate entry fields, enter the rectangle position
X: -5.0,
5.0 Y: -0.2475,
0.2475 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the rectangle:
dX: 7.0,
7.0 dY: 0.495,
0.495 dZ: 0.0,
0.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Feed
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Assign a Perfect E boundary to the Feed
To select the feed:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Feed
2. Click the OK button
To assign the Perfect E boundary
1. Select the menu item HFSS > Boundaries > Assign > Perfect E
2. Perfect E Boundary window
1. Name: PerfE_Feed
2. Infinite Ground Plane: Unchecked
3. Click the OK button
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5.4
Example – Slot Patch
Create Ground
To create the ground:
1. Select the menu item Draw > Rectangle
2. Using the coordinate entry fields, enter the rectangle position
X: -7.0,
7.0 Y: -4.5,
4.5 Z: 0.16,
0.16 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the rectangle:
dX: 12.0,
12.0 dY: 9.0,
9.0 dZ: 0.0,
0.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Ground
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Assign a Perfect E boundary to the Ground
To select the ground:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Ground
2. Click the OK button
To assign the Perfect E boundary
1. Select the menu item HFSS > Boundaries > Assign > Perfect E
2. Perfect E Boundary window
1. Name: PerfE_Ground
2. Infinite Ground Plane: Unchecked
3. Click the OK button
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5.4
Example – Slot Patch
Create Slot Cut Out
To create the cut out:
1. Select the menu item Draw > Rectangle
2. Using the coordinate entry fields, enter the rectangle position
X: -0.0775,
0.0775 Y: -0.7,
0.7 Z: 0.16,
0.16 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the rectangle:
dX: 0.155,
0.155 dY: 1.4,
1.4 dZ: 0.0,
0.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Slot
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View
Complete the Ground
To select the objects ground & slot
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Ground, Slot
2. Click the OK button
To complete the ring:
1. Select the menu item 3D Modeler > Boolean > Subtract
2. Subtract Window
Blank Parts: Ground
Tool Parts: Slot
Clone tool objects before subtract: Unchecked
Click the OK button
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5.4
Example – Slot Patch
Create Patch
To create the patch:
1. Select the menu item Draw > Rectangle
2. Using the coordinate entry fields, enter the rectangle position
X: -2.0,
2.0 Y: -1.5,
1.5 Z: 0.32,
0.32 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the rectangle:
dX: 4.0,
4.0 dY: 3.0,
3.0 dZ: 0.0,
0.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Patch
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Assign a Perfect E boundary to the Trace
To select the trace:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Patch
2. Click the OK button
To assign the Perfect E boundary
1. Select the menu item HFSS > Boundaries > Assign > Perfect E
2. Perfect E Boundary window
1. Name: PerfE_Patch
2. Click the OK button
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5.4
Example – Slot Patch
Set Default Material
To set the default material:
1. Using the 3D Modeler Materials toolbar, choose vacuum
Create Air
To create the air:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: -7.0,
7.0 Y: -4.5,
4.5 Z: -2.0,
2.0 Press the Enter key
2. Using the coordinate entry fields, enter the opposite corner of the box
dX: 12.0,
12.0 dY: 9.0,
9.0 dZ: 4.32,
4.32 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Air
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View
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5.4
Example – Slot Patch
Create Radiation Boundary
Picking the faces:
1. Select the menu item Edit > Select > Faces
2. Graphically select all of the faces of the Air object except the face at Z=0.0cm
To create a radiation boundary
1. Select the menu item HFSS > Boundaries > Radiation
2. Radiation Boundary window
1. Name: Rad1
2. Click the OK button
Create a Radiation Setup
To define the radiation setup
1. Select the menu item HFSS > Radiation > Insert Far Field Setup > Infinite
Sphere
2.
Far Field Radiation Sphere Setup dialog
1. Select the Infinite Sphere Tab
1. Name: ff_2d
2. Phi: (Start: 0, Stop: 90, Step Size: 90)
3. Theta: (Start: -180, Stop: 180, Step Size: 2)
2. Click the OK button
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5.4
Example – Slot Patch
Set Grid Plane
To set the grid plane:
1. Select the menu item 3D Modeler > Grid Plane > YZ
Create Source
To create source:
1. Select the menu item Draw > Rectangle
2. Using the coordinate entry fields, enter the box position
X: -5.0,
5.0 Y: -0.2475,
0.2475 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the base
rectangle:
dX: 0.0,
0.0 dY: 0.495,
0.495 dZ: 0.16,
0.16 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Source
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
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Example – Slot Patch
Assign Excitation
To select the object Source:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Source
2. Click the OK button
Note:
Note You can also select the object from the Model
Tree
To assign lumped port excitation
1. Select the menu item HFSS > Excitations > Assign > Lumped Port
2. Lumped Port : General
1. Name: p1,
p1
2. Resistance: 50
3. Reactance: 0
4. Click the Next button
3. Lumped Port : Terminals
1. Number of Terminals: 1,
2. For T1,
T1 click the Undefined column and select New Line
3. Using the coordinate entry fields, enter the vector position
X: -5.0,
5.0 Y: 0.0,
0.0 Z: 0.16,
0.16 Press the Enter key
4. Using the coordinate entry fields, enter the vertex
dX: 0.0,
0.0 dY: 0.0,
0.0 dZ: -0.16,
0.16 Press the Enter key
5. Click the Next button
6. Click the Finish button
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5.4
Example – Slot Patch
Analysis Setup
Creating an Analysis Setup
To create an analysis setup:
1. Select the menu item HFSS > Analysis Setup > Add Solution Setup
2. Solution Setup Window:
1. Click the General tab::
Solution Frequency:: 2.25 GHz
Maximum Number of Passes: 20
Maximum Delta S: 0.02
2. Click the OK button
Adding a Frequency Sweep
To add a frequency sweep:
1. Select the menu item HFSS > Analysis Setup > Add Sweep
1. Select Solution Setup: Setup1
2. Click the OK button
2. Edit Sweep Window:
1. Sweep Type:: Fast
2. Frequency Setup Type:: Linear Count
Start: 1.0GHz
Stop:: 3.5GHz
Count:: 201
Save Fields: Checked
3. Click the OK button
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Example – Slot Patch
Save Project
To save the project:
1. In an Ansoft HFSS window, select the menu item File > Save As.
2. From the Save As window, type the Filename: hfss_slotpatch
3. Click the Save button
Analyze
Model Validation
To validate the model:
1. Select the menu item HFSS > Validation Check
2. Click the Close button
Note: To view any errors or warning messages, use the Message
Manager.
Analyze
To start the solution process:
1. Select the menu item HFSS > Analyze All
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Example – Slot Patch
Solution Data
To view the Solution Data:
1. Select the menu item HFSS > Results > Solution Data
To view the Profile:
1. Click the Profile Tab.
To view the Convergence:
1. Click the Convergence Tab
Note: The default view is for convergence is Table.
Table Select
the Plot radio button to view a graphical representations of
the convergence data.
To view the Matrix Data:
1. Click the Matrix Data Tab
Note: To view a real-time update of the Matrix Data, set the
Simulation to Setup1, Last Adaptive
2. Click the Close button
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Example – Slot Patch
Create Reports
Create Terminal SS-Parameter Plot - Magnitude
To create a report:
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Terminal S Parameters
2. Display Type: Rectangular
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: Sweep1
2. Domain: Sweep
3. Click the Y tab
1. Category: Terminal S Parameter
2. Quantity: St(p1,p1),
3. Function: dB
4. Click the Add Trace button
4. Click the Done button
4. Select the menu Report 2D > Mark All Traces
1. Click the Min button
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Example – Slot Patch
Far Field Overlays
Create Far Field Overlay
To create a 2D polar far field plot :
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Far Fields
2. Display Type: Radiation Pattern
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: Sweep1
2. Geometry: ff_2d
3. In the Sweeps tab, select Phi under the Name column, and on the
drop list, select Theta.
Theta This changes the primary sweep to Theta.
4. In the Sweeps tab, select the row labeled Freq and select the
frequency 2.3 from the list.
5. In the Mag tab
1. Category: Gain
2. Quantity: GainPhi,
GainPhi, GainTheta
3. Function: dB
4. Click the Add Trace button
6. Click the Done button
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Example – Specific Absorption Rate
Specific Absorption Rate
This example is intended to show you how to create, simulate, and analyze a
simple phantom, which is commonly used to calibrate Specific Absorption Rate
test equipment, using the Ansoft HFSS Design Environment.
With the explosion of consumer demand for wireless devices, consumers and the
media have become aware of and are concerned with the biological effects of
long-term exposure to radio frequency radiation (RFR). To ensure public safety,
the Federal Communication Commission (FCC) has developed safety standards
that wireless devices are required to meet in order to be sold in the US (Similar
guidelines exist in other countries). The quantity used to quantify the amount of
energy absorbed is the Specific Absorption Rate or SAR.
Nominal Design:
Bowl:
Inner radius = 106.5±
106.5±5mm
Thickness = 5±
5±0.5mm.
Opening = d2 =170mm
170mm
εr= 4.6
Antenna:
Overall Length = 168mm
Gap between dipoles = 1mm
Wire Diameter = 3.6mm
Fluid:
εr = 42.9 ±5%
σ=
= 0.9 ±10%
ρ=
= 1 g/cm3
Level = d1 = 13.4 cm
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Example – Specific Absorption Rate
Ansoft HFSS Analysis of Specific Absorption Rate for Flat
Phantom Measurement Standard Outlined in IEEE P1528-2002
Reference: Draft Recommended Standard for Determining the Spatial Peak
Specific Absorption Rate (SAR) in the Human Head from Wireless
Communication Devices: Measurement Technique
The table below summarizes the data from an Ansoft HFSS analysis of flat
phantom models as described in the IEEE draft standard for SAR measurements.
Frequency
(MHz)
1g SAR
10g SAR
Local SAR at
surface
(above
feedpoint)
Local SAR at
surface (y=
2cm offset
from
feedpoint)
300
3.06 (3.0)
2.07 (2.0)
4.63 (4.4)
2.20 (2.1)
450
4.98 (4.9)
3.31 (3.3)
7.59 (7.2)
3.28 (3.2)
835
9.62 (9.5)
6.26 (6.2)
14.71 (14.1)
4.93 (4.9)
900
10.98 (10.8)
7.02 (6.9)
17.01 (16.4)
5.47 (5.4)
1450
29.83 (29.0)
16.50 (16.0)
53.90 (50.2)
6.54 (6.5)
1800
39.36 (38.1)
20.45 (19.8)
74.39 (69.5)
6.85 (6.8)
1900
40.97 (39.7)
21.21 (20.5)
78.02 (72.1)
6.54 (6.6)
2450
55.42 (52.4)
25.42 (24.0)
115 (104.2)
8.09 (7.7)
3000
65.81 (63.8)
26.48 (25.7)
157.66 (140.2)
8.8 (9.5)
HFSS results: Measured data in parenthesis, from Table 8-1 of paper
In general there is excellent agreement between the HFSS simulations and
measurements. The possible exception would be the Local SAR above the
feedpoint. This is likely due to the use of 50 Ω lumped gap sources as an
approximation to the balun feed for the dipoles. Calculation of 1g and 10g SAR
was done via the fields calculator on explicitly defined volumes in the flat
phantom located immediately below the feed point
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Example – Specific Absorption Rate
Getting Started
Launching Ansoft HFSS
1.
To access Ansoft HFSS, click the Microsoft Start button, select Programs,
Programs and select
the Ansoft > HFSS 10 program group. Click HFSS 10
Setting Tool Options
To set the tool options:
Note: In order to follow the steps outlined in this example, verify that the
following tool options are set :
1. Select the menu item Tools > Options > HFSS Options
2. HFSS Options Window:
1. Click the General tab
Use Wizards for data entry when creating new boundaries:: Checked
Duplicate boundaries with geometry:: Checked
2. Click the OK button
3. Select the menu item Tools > Options > 3D Modeler Options.
Options
4. 3D Modeler Options Window:
1. Click the Operation tab
Automatically cover closed polylines:: Checked
2. Click the Drawing tab
Edit property of new primitives:: Checked
3. Click the OK button
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Example – Specific Absorption Rate
Opening a New Project
To open a new project:
1. In an Ansoft HFSS window, click the On the Standard toolbar, or select
the menu item File > New.
2. From the Project menu, select Insert HFSS Design.
Set Solution Type
To set the solution type:
1. Select the menu item HFSS > Solution Type
2. Solution Type Window:
1. Choose Driven Modal
2. Click the OK button
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Example – Specific Absorption Rate
Creating the 3D Model
Set Model Units
To set the units:
1. Select the menu item 3D Modeler > Units
2. Set Model Units:
1. Select Units: mm
2. Click the OK button
Set Default Material
To set the default material:
1. Using the 3D Modeler Materials toolbar, choose Select
2. Select Definition Window:
1. Type pec in the Search by Name field
2. Click the OK button
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Example – Specific Absorption Rate
Create Offset Coordinate System
To create an offset Coordinate System:
1. Select the menu item 3D Modeler > Coordinate System > Create >
Relative CS > Offset
2.
Using the coordinate entry fields, enter the origin
X: 0.0,
0.0 Y: 0.0,
0.0 Z: -6.8,
6.8 Press the Enter key
Create Dipole Antenna Arm 1
To set grid plane
1. Select the menu item 3D Modeler > Grid Plane > XZ
To create the dipole antenna:
1. Select the menu item Draw > Cylinder
2. Using the coordinate entry fields, enter the cylinder position
X:: 0.0, Y:: -84.0, Z:: 0.0, Press the Enter key
3. Using the coordinate entry fields, enter the radius:
dX:: 1.8, dY:: 0.0, dZ:: 0.0, Press the Enter key
4. Using the coordinate entry fields, enter the height:
dX:: 0.0, dY:: 83.5, dZ:: 0.0, Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Dipole
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View. Or press the CTRL+D key
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Example – Specific Absorption Rate
Create Dipole Antenna Arm 2
To create arm 2:
1. Select the menu item Edit > Select All Visible. Or press the CTRL+A key.
2. Select the menu item, Edit > Duplicate > Mirror.
1. Input the anchor point of the mirror plane:
X:: 0.0, Y:: 0.0, Z:: 0.0, Press the Enter key
2. Input the target point of the vector normal to the mirror plane:
dX:: 0.0, dY:: 1.0, dZ:
dZ: 0.0, Press the Enter key
Group the Dipole Antenna Arms
To group the dipole arms:
1. Select the menu item Edit > Select All Visible
2. Select the menu item, 3D Modeler > Boolean > Unite
Set Grid Plane
To set the grid plane:
1. Select the menu item 3D Modeler > Grid Plane > XY
Create Source
To create source:
1. Select the menu item Draw > Rectangle
2. Using the coordinate entry fields, enter the rectangle position
X:: -1.8, Y:: -0.5, Z:: 0.0, Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the rectangle:
dX:: 3.6, dY:: 1.0, dZ:: 0.0, Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Source
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
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Example – Specific Absorption Rate
Assign Excitation
To select the object Source:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Source
2. Click the OK button
Note:
Note You can also select the object from the Model Tree
To assign lumped port excitation
1. Select the menu item HFSS > Excitations > Assign > Lumped Port
2. Lumped Port : General
1. Name: p1,
p1
2. Resistance: 50
3. Reactance: 0
4. Click the Next button
3. Lumped Port : Modes
1. Number of Modes: 1,
2. For Mode 1,
1 click the None column and select New Line
3. Using the coordinate entry fields, enter the vector position
X:: 0.0, Y:: -0.5, Z:: 0.0, Press the Enter key
4. Using the coordinate entry fields, enter the vertex
dX:: 0.0, dY:: 1.0, dZ:: 0.0, Press the Enter key
5. Click the Next button
6. Click the Finish button
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Example – Specific Absorption Rate
Add New Material
To add a new material:
1. Using the 3D Modeler Materials toolbar, choose Select
2. From the Select Definition window, click the Add Material button
3. View/Edit Material Window:
1. For the Material Name type: My_Bowl
2. For the Value of Relative Permittivity type: 4.6
3. Click the OK button
4. Click the OK button
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Example – Specific Absorption Rate
Set Working Coordinate System
To set the working coordinate system:
1. Select the menu item 3D Modeler > Coordinate System > Set Working CS
2. Select Coordinate System Window,
1. From the list, select the CS: Global
2. Click the Select button
Create Bowl
To create the bowl:
1. Select the menu item Draw > Sphere
2. Using the coordinate entry fields, enter the sphere position
X:: 0.0, Y:: 0.0, Z:: 111.5, Press the Enter key
3. Using the coordinate entry fields, enter the radius:
dX:: 111.5, dY:: 0.0, dZ:: 0.0, Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Bowl
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Create Offset Coordinate System
To create an offset Coordinate System:
1. Select the menu item 3D Modeler > Coordinate System > Create >
Relative CS > Offset
2.
Using the coordinate entry fields, enter the origin
X:: 0.0, Y:: 0.0, Z:: 164.0, Press the Enter key
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Example – Specific Absorption Rate
Create the Opening in the Bowl
To select the object Bowl:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Bowl
2. Click the OK button
To select the split the bowl object:
1. Select the menu item 3D Modeler > Boolean > Split
2. Split Window
1. Split Plane: XY
2. Keep Fragments: Negative Side
3. Click the OK button
Add New Material
To add a new material:
1. Using the 3D Modeler Materials toolbar, choose Select
2. From the Select Definition window, click the Add Material button
3. View/Edit Material Window:
1. For the Material Name type: My_BrainFluid
2. For the Value of Relative Permittivity type: 42.9
3. For the Value of Bulk Conductivity type: 0.9
4. Click the OK button
4. Click the OK button
Set Working Coordinate System
To set the working coordinate system:
1. Select the menu item 3D Modeler > Coordinate System > Set Working CS
2. Select Coordinate System Window,
1. From the list, select the CS: Global
2. Click the Select button
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Example – Specific Absorption Rate
Create Brain Fluid
To create the brain fluid:
1. Select the menu item Draw > Sphere
2. Using the coordinate entry fields, enter the sphere position
X: 0.0, Y: 0.0, Z: 111.5, Press the Enter key
3. Using the coordinate entry fields, enter the radius:
dX:
dX: 106.5, dY:
dY: 0.0, dZ:
dZ: 0.0, Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: BrainFluid
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Create the Shell of the Bowl
To select the objects Bowl and BrainFluid:
BrainFluid:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Bowl, BrainFluid
2. Click the OK button
To complete the bowl:
1. Select the menu item 3D Modeler > Boolean > Subtract
2. Subtract Window
Blank Parts: Bowl
Tool Parts: BrainFluid
Clone tool objects before subtracting: Checked
Click the OK button
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Example – Specific Absorption Rate
Create Offset Coordinate System
To create an offset Coordinate System:
1. Select the menu item 3D Modeler > Coordinate System > Create >
Relative CS > Offset
2.
Using the coordinate entry fields, enter the origin
X:: 0.0, Y:: 0.0, Z:: 134.0, Press the Enter key
Set the Fluid Level
To select the object BrainFluid:
BrainFluid:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: BrainFluid
2. Click the OK button
To select the split the bowl object:
1. Select the menu item 3D Modeler > Boolean > Split
2. Split Window
1. Split Plane: XY
2. Keep Fragments: Negative Side
3. Click the OK button
Create a SAR Calculation Line
To create a line:
1. Select the menu item Draw > Line
2. Using the coordinate entry fields, enter the vertex point:
X: 0.0, Y: 0.0, Z: -129.0, Press the Enter key
3. Using the coordinate entry fields, enter the vertex point:
X: 0.0, Y: 0.0, Z: 0.0, Press the Enter key
4. Click the Enter key for the same point to end line creation
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: SAR_Line
3. Click the OK button
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Example – Specific Absorption Rate
Set Working Coordinate System
To set the working coordinate system:
1. Select the menu item 3D Modeler > Coordinate System > Set Working CS
2. Select Coordinate System Window,
1. From the list, select the CS: RelativeCS1
2. Click the Select button
Set Default Material
To set the default material:
1. Using the 3D Modeler Materials toolbar, choose vacuum
Create Air Box
To create the air box:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X:: -155.0, Y:: -155.0, Z:: -44.0, Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the base
rectangle:
dX:: 310.0, dY:: 310.0, dZ:: 257.0, Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Air
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
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Example – Specific Absorption Rate
Create Radiation Boundary
To select the object Air:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Air
2. Click the OK button
To create a radiation boundary
1. Select the menu item HFSS > Boundaries > Assign > Radiation
2. Radiation Boundary Window
Name: Rad1
Click the OK button
Create a Radiation Setup
To define the radiation setup
1. Select the menu item HFSS > Radiation > Insert Far Field Setup > Infinite
Sphere
2.
Far Field Radiation Sphere Setup dialog
1. Select the Infinite Sphere Tab
1. Name: ff_2d
2. Phi: (Start: 0, Stop: 90, Step Size: 90)
3. Theta: (Start: -180, Stop: 180, Step Size: 2)
2. Click the OK button
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Example – Specific Absorption Rate
Analysis Setup
Creating an Analysis Setup
To create an analysis setup:
1. Select the menu item HFSS > Analysis Setup > Add Solution Setup
2. Solution Setup Window:
1. Click the General tab::
Solution Frequency:: 0.835GHz
Maximum Number of Passes: 20
Maximum Delta S: 0.02
2. Click the OK button
Save Project
To save the project:
1. In an Ansoft HFSS window, select the menu item File > Save As.
2. From the Save As window, type the Filename: hfss_sar
3. Click the Save button
Analyze
Model Validation
To validate the model:
1. Select the menu item HFSS > Validation Check
2. Click the Close button
Note: To view any errors or warning messages, use the Message
Manager.
Analyze
To start the solution process:
1. Select the menu item HFSS > Analyze All
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Example – Specific Absorption Rate
Solution Data
To view the Solution Data:
1. Select the menu item HFSS > Results > Solution Data
To view the Profile:
1. Click the Profile Tab.
To view the Convergence:
1. Click the Convergence Tab
Note: The default view is for convergence is Table.
Table Select
the Plot radio button to view a graphical representations of
the convergence data.
To view the Matrix Data:
1. Click the Matrix Data Tab
Note: To view a real-time update of the Matrix Data, set the
Simulation to Setup1, Last Adaptive
2. Click the Close button
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Example – Specific Absorption Rate
Create Reports
Create SS-Parameter Plot vs. Adaptive Pass
Note: If this report is created prior or during the solution process, a real-time
update of the results are displayed
To create a report:
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Modal S Parameters
2. Display Type: Rectangular
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: Adaptive1
2. Click the Y tab
1. Category: Terminal S Parameters
2. Quantity: St(p1,p1),
3. Function: dB
4. Click the Add Trace button
3. Click the Done button
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Example – Specific Absorption Rate
Create SAR Plot
To create a report:
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Fields
2. Display Type: Rectangular
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: LastAdaptive
2. Geometry:: SAR_Line
3. Click the Y tab
1. Category: Calculator Expressions
2. Quantity: Local_SAR,
Local_SAR, Average_SAR
3. Function: <none>
4. Click the Add Trace button
4. Click the Done button
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Example – Specific Absorption Rate
Field Overlays
Create Field Overlay
Select the Global YZ Plane
1. Using the Model Tree, expand Planes
1. Select Global:YZ
2. Select the menu item HFSS > Fields > Fields > E > Mag_E
3. Create Field Plot Window
1. Solution: Setup1 : LastAdaptive
2. Quantity: Mag_E
3. In Volume: BrainFluid
4. Click the Done button
To modify the attributes of a field plot:
1. Select the menu item HFSS > Fields > Modify Plot Attributes
2. Select Plot Folder Window:
1. Select: E Field
2. Click the OK button
3. E-Field1 Window:
1. Click the Scale tab
1. Select Use Limits
2. Min: 2
3. Max: 200
4. Scale: Log
2. Click the Close button
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Example – Specific Absorption Rate
Far Field Overlays
Create Far Field Overlay
To create a 2D polar far field plot :
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Far Fields
2. Display Type: Radiation Pattern
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: LastAdaptive
2. Geometry: ff_2d
3. In the Sweeps tab, select Phi under the Name column, and on the
drop list, select Theta.
Theta This changes the primary sweep to Theta.
4. In the Mag tab
1. Category: Gain
2. Quantity: GainL3Y
3. Function: dB
4. Click the Add Trace button
5. Click the Done button
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5.6
Example – CPW Fed Bowtie Antenna
The CPW Fed Bowtie Antenna
This example is intended to show you how to create, simulate, and analyze a
Coplanar Waveguide (CPW) fed Bowtie antenna using the Ansoft HFSS Design
Environment.
A Lumped Port excitation will be used for the CPW feed.
Copper Cladding w/ Cutout
Sub1 (Dielectric)
2.0mm
Reference:
Guiping Zheng, A. Z. Elsherbeni, and C. E. Smith, “A coplanar waveguide bowtie aperture antenna,” Antennas and Propagation Society International
Symposium,
Symposium 2002. IEEE, Volume 1, 16-21 June 2002, Page 564-567.
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Example – CPW Fed Bowtie Antenna
Design Review
1.
2.
The CPW slots and antenna shape will be openings in a metallized plane. Consider
how the port will look
The antenna will be analyzed over a frequency range of 8 – 12 GHz. How large
should the air volume be?
Getting Started
Launching Ansoft HFSS
1.
To access Ansoft HFSS, click the Microsoft Start button, select Programs,
Programs and select
the Ansoft > HFSS 10 program group. Click HFSS 10
Setting Tool Options
To set the tool options:
Note: In order to follow the steps outlined in this example, verify that the
following tool options are set :
1. Select the menu item Tools > Options > HFSS Options
2. HFSS Options Window:
1. Click the General tab
Use Wizards for data entry when creating new boundaries:: Checked
Duplicate boundaries with geometry:: Checked
2. Click the OK button
3. Select the menu item Tools > Options > 3D Modeler Options.
Options
4. 3D Modeler Options Window:
1. Click the Operation tab
Automatically cover closed polylines:: Checked
2. Click the Drawing tab
Edit property of new primitives:: Checked
3. Click the OK button
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Example – CPW Fed Bowtie Antenna
Opening a New Project
To open a new project:
1. In an Ansoft HFSS window, click the On the Standard toolbar, or
select the menu item File > New.
2. From the Project menu, select Insert HFSS Design.
Set Solution Type
To set the solution type:
1. Select the menu item HFSS > Solution Type
2. Solution Type Window:
1. Choose Driven Modal
2. Click the OK button
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Example – CPW Fed Bowtie Antenna
Creating the 3D Model
Set Model Units
To set the units:
1. Select the menu item 3D Modeler > Units
2. Set Model Units:
1. Select Units: mm
2. Click the OK button
Set Default Material
To set the default material:
1. Using the 3D Modeler Materials toolbar, choose Select
2. Select Definition Window:
1. Type “Arlon
Arlon C” in the Search by Name field and select Arlon CuClad
217 (tm) from the table below.
2. Click the OK button
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Example – CPW Fed Bowtie Antenna
Create Substrate
To create the substrate:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: -17.0,
17.0 Y: -32,
32 Z: 0.0,
0.0 Press the Enter key
2. Using the coordinate entry fields, enter the opposite corner of the box
dX: 34.0,
34.0 dY: 64.0,
64.0 dZ: -2.0,
2.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Sub1
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View or press the CTRL+D key
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Example – CPW Fed Bowtie Antenna
Create Copper Cladding
To create the ground:
1. Select the menu item Draw > Rectangle
2. Using the Drawing Plane dropdown, set the current plane to XY
3. Using graphical snapping, draw a rectangle to cover the top face of Sub1
First corner snap X: -17.0,
17.0 Y: -32.0,
32.0 Z: 0.0
Second corner snap dX: 34.0,
34.0 dY: 64.0,
64.0 dZ: 0.0
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: CuClad
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View
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Example – CPW Fed Bowtie Antenna
Assign a Finite Conductivity boundary to the Copper Cladding
To select the rectangle:
1. In the 3D Modeler Design Tree, right-click on Model and select Expand All
2. Find the entry name CuClad under the category Not Assigned and click it to
select.
To assign the Finite Conductivity boundary
1. Right-Click on the 3D Modeler view, and select the menu item Assign
Boundary > Finite Conductivity
2.
Finite Conductivity Boundary window
1. Name: Cu_bound
2. Beneath Permeability, Check Use Material
3. Click the block showing Arlon CuClad 217 (tm) to open the Material
Listing
4. Type “co
co”
co in the Name field and select copper from the table below,
and click OK
5. Leave Unchecked Infinite Ground Plane
6. Click the OK button
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Example – CPW Fed Bowtie Antenna
Create Feed Cut Out
To create the feed gap:
1. Select the menu item Draw > Rectangle
2. Using the coordinate entry fields, enter the first corner position
X: -0.5,
0.5 Y: 0.5,
0.5 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the diagonal corner:
dX: 13.0,
13.0 dY: 0.6,
0.6 dZ: 0.0,
0.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. Leave the Value of Name as Rect1
3. Click the OK button
Create Bowtie arm
To create the bowtie polygon:
1. Select the menu item Draw > Line
2. Snap to the first vertex position
Location X: -0.5,
0.5 Y: 0.5,
0.5 Z: 0.0
3. Using the coordinate entry fields, enter the second vertex
X: -6.7,
6.7 Y: 21.0,
21.0 Z: 0.0,
0.0 Press the Enter key
4. Using the coordinate entry fields, enter the third vertex
X: 6.0,
6.0 Y: 21.0,
21.0 Z: 0.0,
0.0 Press the Enter key
5. Using the coordinate entry fields, enter the fourth vertex
X: 0.5,
0.5 Y: 1.1,
1.1 Z: 0.0,
0.0 Press the Enter key
6. Double-click on the starting vertex to finish and close the polyline.
To set the name:
1. Select the Attribute tab from the Properties window.
2. Set the Value of Name as Bowtie
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View
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Example – CPW Fed Bowtie Antenna
Unite Feed and Bowtie
To select the objects Bowtie and Rect1
1. In the 3D Modeler Design Tree, right-click on Model and select Expand All
2. Under the category Unassigned select Bowtie and Rect1. (Use the CTRL
key to select multiple objects)
To complete the bowtie arm:
1. Select the menu item 3D Modeler > Boolean > Unite. (The united object
will take the name of the first item selected, Bowtie
Mirror the Bowtie
To create the other side of the Bowtie:
1. Select the object Bowtie from the 3D Modeler Design Tree
2. Select the menu item Edit > Duplicate > Mirror
3. Set the starting vertex of the mirror normal using the coordinate entry box:
Location X: 0, Y: 0, Z: 0
4. Set the ending vertex of the mirror normal using the coordinate entry box
Location dX: 0, dY: 1.0,
1.0 dZ: 0.0
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Example – CPW Fed Bowtie Antenna
Open the Bowtie Aperture in the Copper Cladding
To subtract the Bowtie from the Cladding
1. Select the objects Bowtie,
Bowtie Bowtie_1 and CuClad from the 3D Modeler
Design Tree
2. Select the menu item 3D Modeler > Boolean > Subtract
3. Subtract Window
Blank Parts: CuClad
Tool Parts: Bowtie,
Bowtie Bowtie_1
Clone tool objects before
subtracting: Checked
Click the OK button
Assign a Mesh Operation on the Bowtie geometry
To assign the mesh operation:
1. Select the objects Bowtie and Bowtie_1 from the 3D Modeler
Design Tree
2. Select the menu item HFSS > Mesh Operation > Assign > On Selection >
Length Based
3.
4.
Element Length Based Refinement Window :
Name Length1
Restrict Length of Elements:
Checked
Maximum Length of Elements:
3 mm
Restrict the Number of Elements:
Unchecked
Click the OK button
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Example – CPW Fed Bowtie Antenna
Create the Lumped Port
To draw the port rectangle:
1. Select the menu item Draw > Rectangle
2. Using the coordinate entry fields, enter the first corner position
X: 12.5,
12.5 Y: -0.5,
0.5 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the diagonal corner:
dX: -1.0,
1.0 dY: 1.0,
1.0 dZ: 0.0,
0.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. Enter the Value of Name as P1
3. Click the OK button
To select the object Port1:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: P1
2. Click the OK button
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Example – CPW Fed Bowtie Antenna
Create the Lumped port, cont.
To assign lumped port excitation
1. Select the menu item HFSS > Excitations > Assign > Lumped Port
2. Lumped Port : General
1. Name: Port1
2. Resistance: 50 ohm
3. Reactance: 0 ohm
4. Click the Next button
3. Lumped Port : Modes
1. Number of Modes: 1,
2. In the row for Mode 1, click None in the Integration Line column and
select New Line
3. Using the coordinate entry fields, enter the vector position
X: 12.5,
12.5 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
4. Using the coordinate entry fields, enter the vertex
dX: -1.0,
1.0 dY: 0.0,
0.0 dZ: 0.0,
0.0 Press the Enter key
4. Click the Finish button
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Example – CPW Fed Bowtie Antenna
Set Default Material
To set the default material:
1. Using the 3D Modeler Materials toolbar, choose vacuum
Create the Air Volume
The analysis will be performed between 8 – 12 GHz. Therefore the minimum
distance between the air volume wall and the radiating aperture should be one
quarter wavelength at 8 GHz, or 0.25*(3e11/8e9) = 9.375mm. The following
dimensions round this up to 9.5mm spacing.
To create the air volume
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the starting position
X: -17.0,
17.0 Y: -32.0,
32.0 Z: -9.5 Press the Enter key
3. Using the coordinate entry fields, enter the diagonal corner:
dX: 34.0,
34.0 dY: 64.0,
64.0 dZ: 19.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: AirBox
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
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Example – CPW Fed Bowtie Antenna
Assign the Radiation Boundary
To select the air volume
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: AirBox
2. Click the OK button
To assign the boundary:
1. Right-click in the graphical view and select the Menu pick Assign Boundary >
Radiation
2. For the Value of Name type: Rad1
3. Click the OK button
Create a Radiation Setup
To define the radiation setup
1. Select the menu item HFSS > Radiation > Insert Far Field Setup > Infinite
Sphere
2.
Far Field Radiation Sphere Setup dialog
1. Select the Infinite Sphere Tab
1. Name: ff_all
2. Phi: (Start: -90, Stop: 90,
Step Size: 10)
3. Theta: (Start: 0, Stop: 360,
Step Size: 10)
2. Click the OK button
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Example – CPW Fed Bowtie Antenna
Analysis Setup
Creating an Analysis Setup
To create an analysis setup:
1. Select the menu item HFSS > Analysis Setup > Add Solution Setup
2. Solution Setup Window:
1. Click the General tab::
Solution Frequency:: 10 GHz
Maximum Number of Passes: 6
Maximum Delta S: 0.01
2. Click the OK button
Adding a Frequency Sweep
To add a frequency sweep:
1. Select the menu item HFSS > Analysis Setup > Add Sweep
1. Select Solution Setup: Setup1
2. Click the OK button
2. Edit Sweep Window:
1. Sweep Type:: Fast
2. Frequency Setup Type:: Linear Step
Start: 8.0GHz
Stop:: 12.0GHz
Step:: 0.02
Save Fields: Checked
3. Click the OK button
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Example – CPW Fed Bowtie Antenna
Save Project
To save the project:
1. In an Ansoft HFSS window, select the menu item File > Save As.
2. From the Save As window, type the Filename: hfss_cpwbowtie
3. Click the Save button
Analyze
Model Validation
To validate the model:
1. Select the menu item HFSS > Validation Check
2. Click the Close button
Note: To view any errors or warning messages, use the Message
Manager.
Analyze
To start the solution process:
1. Select the menu item HFSS > Analyze All
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Example – CPW Fed Bowtie Antenna
Solution Data
To view the Solution Data:
1. Select the menu item HFSS > Results > Solution Data
To view the Profile:
1. Click the Profile Tab.
To view the Convergence:
1. Click the Convergence Tab
Note: The default view is for convergence is Table.
Table Select
the Plot radio button to view a graphical representations of
the convergence data.
To view the Matrix Data:
1. Click the Matrix Data Tab
Note: To view a real-time update of the Matrix Data, set the
Simulation to Setup1, Last Adaptive during solution.
2. Click the Close button when done viewing or simulation complete.
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Example – CPW Fed Bowtie Antenna
Create Reports
Create Modal SS-Parameter Plot - Magnitude
To create a report:
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Modal S Parameters
2. Display Type: Rectangular
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: Sweep1
2. Domain: Sweep
3. Click the Y tab
1. Category: S Parameter
2. Quantity: S(Port1,Port1),
3. Function: dB
4. Click the Add Trace button
4. Click the Done button
4. Select the menu Report 2D > Mark All Traces
1. Click the Min button to see the best match displayed
5. Right-click on the graph and select Exit Marker Mode
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Example – CPW Fed Bowtie Antenna
Create Reports
Create Modal SS-Parameter Plot – Impedance
To create a report:
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Modal S Parameters
2. Display Type: Rectangular
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: Sweep1
2. Domain: Sweep
3. Click the Y tab
1. Category: Z Parameter
2. Quantity: Z(Port1,Port1),
3. Function: re
4. Click the Add Trace button
5. Function: im
6. Click the Add Trace button
7. In the tabular listing of assigned Traces, click the Y1
entry beside im(Z(Port1,Port1)) and from the dropdown
switch to Y2
4. Click the Done button
5. Note: Since a Lumped Port excitation was used, this plot is not
deembedded up to the aperture itself.
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Example – CPW Fed Bowtie Antenna
Far Field Overlays
Create Far Field Overlay
To create a 2D polar far field plot :
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Far Fields
2. Display Type: Radiation Pattern
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: Sweep1
2. Geometry: ff_all
3. In the Sweeps tab:
1. Select Phi under the Name column, and on the drop list,
select Theta.
Theta This changes the primary sweep to Theta.
2. Highlight the second row which now reads Phi.
Phi Uncheck All Values above the list to the right. Highlight only -90deg
and 0deg from this list.
3. Select the row labeled Freq and select the frequency 10.44
GHz from the list.
4. In the Mag tab
1. Category: Directivity
2. Quantity: DirTotal
3. Function: dB
4. Click the Add Trace button
5. Click the Done button
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Example – CPW Fed Bowtie Antenna
To create a 3D polar far field plot :
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Far Fields
2. Display Type: 3D Polar Plot
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: Sweep1
2. Geometry: ff_all
3. In the Sweeps tab, select the row labeled Freq and select the
frequency 10.44 GHz from the list.
4. In the Mag tab
1. Category: Gain
2. Quantity: GainTotal
3. Function: dB
4. Click the Add Trace button
5. Click the Done button
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Example – Endfire Antenna Array
The Endfire Waveguide Array
This example is intended to show you how to create, simulate, and analyze a
Waveguide array antenna using the Ansoft HFSS Design Environment
A WavePort excitation will be used for the feed
PMLs (Perfectly Matched Layers) will be used for the radiation load
Master/Slave boundary conditions will be used to create the array
Reference:
[1] C.A. Balanis, “Antenna Theory – Analysis and Design”, Harper and Row,
Publishers, Inc., 1982, ISBN 0-06-040458-2, section 6.2.
[2] S.W. Lee and W.R. Jones, “On the Suppression of Radiation Nulls and
Broadband Impedance Matching of Rectangular Waveguide Phased Arrays”,
IEEE Trans. on Antennas Propagat., vol. AP-19, No. 1, pp. 41-51, Jan. 1971.
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Example – Endfire Antenna Array
Design Review
1.
2.
Instead of modeling the entire array, we will make use of the master/slave boundary
conditions and only model a unit cell.
Since the Master/Slave boundary conditions also allow us to change the scan angle,
we will need a better radiation load on the top of the antenna than a simple radiation
boundary condition. We will need to use a PML.
Ansoft HFSS Design Environment
The following features of the Ansoft HFSS Design Environment are used to create
this passive device model
3D Solid Modeling
Primitives: Box
Other: Perfectly Matched Layer (PML)
Boundaries/Excitations
Ports: Wave Ports
Boundaries: Master/Slave, Impedance
Analysis
Sweep:: None
Results
Cartesian plotting
Field Overlays:
Radiation Patterns
Optimetrics
Parametric sweep
Getting Started
Launching Ansoft HFSS
1.
To access Ansoft HFSS, click the Microsoft Start button, select Programs,
Programs and select
the Ansoft > HFSS 10 program group. Click HFSS 10
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Example – Endfire Antenna Array
Setting Tool Options
To set the tool options:
Note: In order to follow the steps outlined in this example, verify that the
following tool options are set :
1. Select the menu item Tools > Options > HFSS Options
2. HFSS Options Window:
1. Click the General tab
Use Wizards for data entry when creating new boundaries::
Checked
Duplicate boundaries with geometry:: Checked
2. Click the OK button
3. Select the menu item Tools > Options > 3D Modeler Options.
Options
4. 3D Modeler Options Window:
1. Click the Operation tab
Automatically cover closed polylines:: Checked
2. Click the Drawing tab
Edit property of new primitives:: Checked
3. Click the OK button
Opening a New Project
To open a new project:
1. In an Ansoft HFSS window, click the On the Standard toolbar, or
select the menu item File > New.
2. From the Project menu, select Insert HFSS Design.
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Example – Endfire Antenna Array
Set Solution Type
To set the solution type:
1. Select the menu item HFSS > Solution Type
2. Solution Type Window:
1. Choose Driven Modal
2. Click the OK button
Creating the 3D Model
Set Model Units
To set the units:
1. Select the menu item 3D Modeler > Units
2. Set Model Units:
1. Select Units: in
2. Click the OK button
Set Default Material
To set the default material:
1. Using the 3D Modeler Materials toolbar, make sure that vacuum is the
default material
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Example – Endfire Antenna Array
Create Waveguide
To create the waveguide:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: 0, Y: 0, Z: 0, Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the box
dX: 0.4,
0.4 dY: 0.9,
0.9 dZ: 1.0,
1.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: waveguide
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View or press the CTRL+D keys
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Example – Endfire Antenna Array
Create Airbox
To create the airbox:
airbox:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: -0.05,
0.05 Y: -0.05,
0.05 Z: 1.0,
1.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the box
dX: 0.5,
0.5 dY: 1.0,
1.0 dZ: 1.0,
1.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: airbox
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View
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Example – Endfire Antenna Array
Create PML load
To select the proper face of the airbox:
airbox:
1. Select the menu item Edit > Select > Faces
2. Graphically pick the top face of the airbox that was just created.
To assign the PML boundary
1. Select the menu item HFSS > Boundaries > PML Setup Wizard
2. PML Setup Wizard: Cover Objects
1. Select: Create PML Cover Objects on Selected Faces
2. Uniform Layer Thickness: 0.2in
3. Click the Next button
3. PML Setup Wizard: Material Parameters
1. Select: PML Objects accept Free Radiation
1. Min Frequency:: 9 GHz
2. Minimum Radiating Distance:: 1in
3. Click the Next button
2. Review settings on the PML Setup Wizard: Summary page
3. Click the Finish button
Top face selected
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Example – Endfire Antenna Array
Make the PML object visible
By default, the PML wizard will turn off visibility of the PML object once it is
created. We want to turn it back on again.
1. Select the menu item View > Active View Visiblility
2. Check the box next to PML_airbox1
3. Click Done
Create the Master/Slave boundary objects
Set Grid Plane
To set the grid plane:
1. Select the menu item 3D Modeler > Grid Plane > YZ
Draw the Master / Slave objects
To draw the first Master/Slave rectangle:
1. Select the menu item Draw > Rectangle
2. Using the coordinate entry fields, enter the box position
X: 0.45,
0.45 Y: -0.05,
0.05 Z: 1.0,
1.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the rectangle
dX: 0, dY: 1.0,
1.0 dZ: 1.2,
1.2 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: master1
3. Click the OK button
To set the grid plane:
1. Select the menu item 3D Modeler > Grid Plane > XZ
To draw the second Master/Slave rectangle:
1. Select the menu item Draw > Rectangle
2. Using the coordinate entry fields, enter the box position
X: -0.05,
0.05 Y: -0.05,
0.05 Z: 1.0,
1.0 Press the Enter key
2. Using the coordinate entry fields, enter the opposite corner of the rectangle
dX: 0.5,
0.5 dY: 0, dZ: 1.2,
1.2 Press the Enter key
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Example – Endfire Antenna Array
Create the Master/Slave boundary objects (continued)
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: master2
3. Click the OK button
To duplicate the objects to create the slaves
1. Select the menu item Edit > Select > Objects
2. Select the menu item Edit > Select > By Name
3. Select the object, master1
4. Select the menu item Edit > Duplicate > Along Line
5. Using the coordinate entry fields, enter the start position of the duplicate
vector
X: 0, Y: 0, Z: 0, Press the Enter key
6. Using the coordinate entry fields, enter the end point of the duplicate vector
dX: -0.5,
0.5 dY: 0, dZ: 0, Press the Enter key
7. When the dialog box pops up requesting the total number of copies,
change the value to 2, Press the OK button.
8. Repeat this process for the object master2 using a duplicate vector of
<0,1,0>
Change Slave boundary names
To change the duplicated master boundary to slave boundary
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: master1_1
2. Click the OK button
3. Select the menu Item: Edit > Properties
4. Change the name to: slave1
5. Repeat the process for master2_1 slave2
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Example – Endfire Antenna Array
Assign Master/Slave Boundaries
To create a Master boundary
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: master1
2. Click the OK button
3. Select the menu item HFSS > Boundaries > Assign > Master
4. Master Boundary window
1. Name: master1
2. Coordinate System: U Vector: click Undefined pulldown
3. Using the coordinate entry fields, enter the start position
X:0.45
0.45,
1.0,
0.45 Y: -0.05, Z:1.0
1.0 Press the Enter key
4. Using the coordinate entry fields, enter the stop position of the
vector
dX: 0, dY: 1, dZ: 0, Press the Enter key
5. For the V vector, check the Reverse Direction box
Repeat the process for master2 using the following points:
1. Using the coordinate entry fields, enter the start position
X:0.45
0.45,
1.0,
0.45 Y: -0.05, Z:1.0
1.0 Press the Enter key
2. Using the coordinate entry fields, enter the stop position of the vector
dX::-0.5,
0.5 dY: 0, dZ: 0, Press the Enter key
To create a Slave boundary
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: slave1
2. Click the OK button
3. Select the menu item HFSS > Boundaries > Assign > Slave
4. Slave Boundary window
1. Name: slave1
2. Master Boundary: click on Undefined pulldown and select Master1
3. Coordinate System: U Vector: click Undefined pulldown
4. Using the coordinate entry fields, enter the start position
X:-0.05
0.05,
1.0,
0.05 Y: -0.05, Z:1.0
1.0 Press the Enter key
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Example – Endfire Antenna Array
Assign Master / Slave Boundaries (continued)
To create a Slave boundary (continued)
1. Using the coordinate entry fields, enter the stop position of the
vector
dX: 0, dY: 1, dZ: 0, Press the Enter key
2. Click the Next button
3. Make sure that Use Scan Angles To Calculate Phase Delay is
checked
1. For Phi,
Phi enter 0 deg
2. For Theta,
Theta enter a variable name theta_scan,
theta_scan and hit Enter
3. For the Add Variable dialog, enter 30deg for theta_scan
Repeat the process for slave2:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: slave2
2. Click the OK button
3. Select the menu item HFSS > Boundaries > Assign > Slave
4. Slave Boundary window
1. Name: slave2
2. Master Boundary: click on Undefined pulldown and select Master2
3. Coordinate System: U Vector: click Undefined pulldown
4. Using the coordinate entry fields, enter the start position
X:0.45
0.45,
1.0,
0.45 Y: 0.95, Z:1.0
1.0 Press the Enter key
5. Using the coordinate entry fields, enter the stop position of the
vector
dX::-0.5,
0.5 dY: 0, dZ: 0, Press the Enter key
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Example – Endfire Antenna Array
Assign Impedance Boundary
To create the impedance boundary on the PML object:
1. Select the menu item Edit > Select > Faces
2. Graphically pick the top face of the PML object
3. Select the menu item: HFSS > Boundaries > Assign > Impedance
4. Name: TopLoad
5. Resistance: 377*cos(theta_scan
377*cos(theta_scan)
cos(theta_scan
6. Reactance: 0
Create WavePort
To assign waveport to waveguide object:
1. Select the menu item Edit > Select > By Name
2. Select Face dialog: Select the object waveguide from the left column
3. Select different FaceIDs until the bottom face of the waveguide is
highlighted.
4. Click OK
Ansoft High Frequency Structure Simulator v10 User’s Guide
5.7-12
5.7
Example – Endfire Antenna Array
Create WavePort (continued)
To assign waveport to waveguide object (continued):
1. Select the menu item HFSS > Excitation > Assign > WavePort
2. Name: p1
3. Click Next
4. Wave Port: Modes
1. Click Next
5. Wave Port: Post-Processing
1. Click Finish
Create Facelist for Post-Processing
Far field calculations cannot be made on the impedance surface nor on the PML
object. We need to create a facelist on which to calculate the radiation patterns.
To create the facelist:
facelist:
1. Select the menu item Edit > Select > Faces
2. Select the menu item Edit > Select > By Name
3. Select Face dialog: Select the object airbox from the left column
4. Select different FaceIDs until the top face of the waveguide is highlighted.
5. Click OK
Ansoft High Frequency Structure Simulator v10 User’s Guide
5.7-13
5.7
Example – Endfire Antenna Array
Analysis Setup
Creating an Analysis Setup
To create an analysis setup:
1. Select the menu item HFSS > Analysis Setup > Add Solution Setup
2. Solution Setup Window:
1. Click the General tab::
Solution Frequency:: 9.25 GHz
Maximum Number of Passes: 5
Maximum Delta S: 0.0001
2. Click the OK button
Create a Radiation Setup
To define the radiation setup
1. Select the menu item HFSS > Radiation > Insert Far Field Setup > Infinite
Sphere
2.
Far Field Radiation Sphere Setup dialog
1. Select the Infinite Sphere Tab
1. Name: ff_all
2. Phi: (Start: 0, Stop: 0,
Step Size: 10)
3. Theta: (Start: 0, Stop: 360,
Step Size: 2)
2. Switch to the Radiation Surface tab
3. Make sure that Use Custom Radiation Surface is enabled and
Facelist1 has been selected
4. Click the OK button
Ansoft High Frequency Structure Simulator v10 User’s Guide
5.7-14
5.7
Example – Endfire Antenna Array
Save Project
To save the project:
1. In an Ansoft HFSS window, select the menu item File > Save As.
2. From the Save As window, type the Filename: hfss_pmlarray
3. Click the Save button
Analyze
Model Validation
To validate the model:
1. Select the menu item HFSS > Validation Check
2. Click the Close button
Note: To view any errors or warning messages, use the Message
Manager.
Analyze
To start the solution process:
1. Select the menu item HFSS > Analyze All
Ansoft High Frequency Structure Simulator v10 User’s Guide
5.7-15
5.7
Example – Endfire Antenna Array
Solution Data
To view the Solution Data:
1. Select the menu item HFSS > Results > Solution Data
To view the Profile:
1. Click the Profile Tab.
To view the Convergence:
1. Click the Convergence Tab
Note: The default view is for convergence is Table.
Table Select
the Plot radio button to view a graphical representations of
the convergence data.
To view the Matrix Data:
1. Click the Matrix Data Tab
Note: To view a real-time update of the Matrix Data, set the
Simulation to Setup1, Last Adaptive during solution.
2. Click the Close button when done viewing or simulation complete.
Ansoft High Frequency Structure Simulator v10 User’s Guide
5.7-16
5.7
Example – Endfire Antenna Array
Far Field Plots
Create Far Field Plot
To create a 2D polar far field plot :
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Far Fields
2. Display Type: Radiation Pattern
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: LastAdaptive
2. Geometry: ff_all
3. In the Sweeps tab:
1. Select Phi under the Name column, and on the drop list,
select Theta.
Theta This changes the primary sweep to Theta.
4. In the Mag tab
1. Category: Directivity
2. Quantity: DirTotal
3. Function: dB
4. Click the Add Trace button
5. Click the Done button
Ansoft High Frequency Structure Simulator v10 User’s Guide
5.7-17
5.7
Example – Endfire Antenna Array
Add Array Factor to Plot
To setup array factor:
1. Select the menu item HFSS > Radiation > Antenna Array Setup
2. Select the radio button for Regular Array Setup
3. Switch to the Regular Array tab
4. First Cell Position:
X:0in
0in,
0 in
0in Y: 0 in, Z:0
5. Directions: U vector
X:1
1, Y: 0, Z:0
0
6. Directions: V Vector
X:0
0, Y: 1, Z:0
0
7. Distance Between Cells
U Direction: 0.5 in
V Direction 1 in
8. Number of Cells
U Direction: 25
V Direction 25
9. Scan Definition: Use Scan Angles
Theta: theta_scan
Phi: 0 deg
Ansoft High Frequency Structure Simulator v10 User’s Guide
5.7-18
5.7
Example – Endfire Antenna Array
Add Array Factor to Plot (continued)
Ansoft High Frequency Structure Simulator v10 User’s Guide
5.7-19
5.7
Example – Endfire Antenna Array
Optimetrics Setup – Parametric Sweep
For this array design, we want to see the effect of scan angle on the input match
of the antenna. To do this, we must sweep the scan angle with a parametric
sweep.
Add a Parametric Sweep
1.
2.
Select the menu item HFSS > Optimetrics Analysis > Add Parametric
Setup Sweep Analysis Window:
1. Click the Sweep Definitions tab::
1. Click the Add button
2. Add/Edit Sweep Dialog
1. Select Variable: theta_scan (this is the only variable defined,
so it is greyed out)
2. Select Linear Step
3. Start: 0deg
4. Stop: 60deg
5. Step: 10deg
6. Click the Add button
7. Click the OK button
Analyze Parametric Sweep
To start the solution process:
1. Expand the Project Tree to display the items listed under Optimetrics
2. Right-click the mouse on ParametricSetup1 and choose Analyze
Optimetrics Results
To view the Optimetrics Results:
1. Select the menu item HFSS > Optimetrics Analysis > Optimetrics Results
2. Select the Profile Tab to view the solution progress for each setup.
3. Click the Close button when you are finished viewing the results
Ansoft High Frequency Structure Simulator v10 User’s Guide
5.7-20
5.7
Example – Endfire Antenna Array
Create SS-Parameter Plot – S11 at each θ
To create a report:
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Modal S Parameters
2. Display Type: Rectangular Plot
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: LastAdaptive
2. Click the Sweeps tab
1. Select Sweep Design and Project variable values
3. In the Sweeps tab:
1. Select Freq under the Name column, and on the drop list,
select theta_scan.
theta_scan This changes the primary sweep to
theta_scan.
4. Click the Y tab
1. Category: S Parameter
2. Quantity: S(p1,p1)
3. Function: dB
4. Click the Add Trace button
5. Click the Done button
Ansoft High Frequency Structure Simulator v10 User’s Guide
5.7-21
Chapter 6.0
Chapter 6.0 – Microwave Examples
6.1 – Magic T
6.2 – Coax Bend
6.3 – Ring Hybrid
6.4 – Coax Stub
Includes Optimetrics Example
6.5 – Microstrip - Wave Ports
Includes Optimetrics Example
6.6 – Dielectric Resonator
Ansoft High Frequency Structure Simulator v10 User’s Guide
6.1
The Magic T
This example is intended to show you how to create, simulate, and analyze a Magic
T, which is a commonly used microwave device, using the Ansoft HFSS Design
Environment.
Length
Height
Width
Port1
Nominal Design:
Waveguide:
Width = 50.0 mm
Port2
Height = 20.0 mm
Length = 50.0 mm
Port3
Ansoft High Frequency Structure Simulator v10 User’s Guide
Port4
6.1-1
6.1
Ansoft HFSS Design Environment
The following features of the Ansoft HFSS Design Environment are used to create
this passive device model
3D Solid Modeling
Primitives: Box
Boolean Operations: Unite, Duplicate
Excitations
Ports: Wave Ports
Analysis
Sweep:: Fast Frequency
Results
Cartesian plotting
Fields
3D Field Plots, Animations
Ansoft High Frequency Structure Simulator v10 User’s Guide
6.1-2
6.1
Getting Started
Launching Ansoft HFSS
1.
To access Ansoft HFSS, click the Microsoft Start button, select Programs,
Programs and select
the Ansoft, HFSS 10 program group. Click HFSS 10.
10
Setting Tool Options
To set the tool options:
Note: In order to follow the steps outlined in this example, verify that the
following tool options are set :
1. Select the menu item Tools > Options > HFSS Options
2. HFSS Options Window:
1. Click the General tab
Use Wizards for data entry when creating new boundaries:: Checked
Duplicate boundaries with geometry:: Checked
2. Click the OK button
3. Select the menu item Tools > Options > 3D Modeler Options.
Options
4. 3D Modeler Options Window:
1. Click the Operation tab
Automatically cover closed polylines:: Checked
2. Click the Drawing tab
Edit property of new primitives:: Checked
3. Click the OK button
Ansoft High Frequency Structure Simulator v10 User’s Guide
6.1-3
6.1
Opening a New Project
To open a new project:
1. In an Ansoft HFSS window, click the On the Standard toolbar, or select
the menu item File > New.
2. From the Project menu, select Insert HFSS Design.
Set Solution Type
To set the solution type:
1. Select the menu item HFSS > Solution Type
2. Solution Type Window:
1. Choose Driven Modal
2. Click the OK button
Ansoft High Frequency Structure Simulator v10 User’s Guide
6.1-4
6.1
Creating the 3D Model
Set Model Units
To set the units:
1. Select the menu item 3D Modeler > Units
2. Set Model Units:
1. Select Units: mm
2. Click the OK button
Set Default Material
To set the default material:
1. Using the 3D Modeler Materials toolbar, choose vacuum
Create Top Arm
To create arm 1:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: -25.0,
25.0 Y: -10.0,
10.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the base
rectangle:
dX: 50.0,
50.0 dY: 20.0,
20.0 dZ: 75.0, Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Arm
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Or press the CTRL+D key
Ansoft High Frequency Structure Simulator v10 User’s Guide
6.1-5
6.1
Create Wave Port Excitation 1
Picking the port face:
1. Select the menu item Edit > Select > Faces
2. Graphically select the top face of the arm at Z=75mm
To assign wave port excitation
1. Select the menu item HFSS > Excitations > Assign > Wave Port
2. Wave Port : General
1. Name: p1
2. Click the Next button
3. Wave Port : Modes
1. Click the Next button
4. Wave Port : Post Processing
1. Click the Finish button
Top face
Wave Port Face
Ansoft High Frequency Structure Simulator v10 User’s Guide
6.1-6
6.1
Set Object Selection
Set select to objects
1. Select the menu item Edit > Select > Objects
Create Arm 2
To create arm 2:
1. Select the menu item Edit > Select All Visible. Or press the CTRL+A key.
2. Select the menu item, Edit > Duplicate > Around Axis.
1. Axis: X
2. Angle: 90
3. Total Number: 2
4. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Create Arm 3 & 4
To select the object Arm_1:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Arm_1
2. Click the OK button
To create arm 3 & 4:
1. Select the menu item, Edit > Duplicate > Around Axis.
1. Axis: Z
2. Angle: 90
3. Total Number: 3
4. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Ansoft High Frequency Structure Simulator v10 User’s Guide
6.1-7
6.1
Group the Arms
To group the arms:
1. Select the menu item Edit > Select All Visible. Or press the CTRL+A key.
2. Select the menu item, 3D Modeler > Boolean > Unite
To fit the view:
1. Select the menu item View > Fit All > Active View.
Boundary Display
To verify the boundary setup:
1. Select the menu item HFSS > Boundary Display (Solver View)
2. From the Solver View of Boundaries, toggle the Visibility check box for the
boundaries you wish to display.
Note: The background (Perfect Conductor) is displayed as the outer
boundary.
Note: The Perfect Conductors are displayed as the smetal boundary.
Note: Select the menu item, View > Visibility to hide all of the
geometry objects. This makes it easier to see the boundary
3. Click the Close button when you are finished
Ansoft High Frequency Structure Simulator v10 User’s Guide
6.1-8
6.1
Analysis Setup
Creating an Analysis Setup
To create an analysis setup:
1. Select the menu item HFSS > Analysis Setup > Add Solution Setup
2. Solution Setup Window:
1. Click the General tab::
Solution Frequency:: 4.0GHz
Maximum Number of Passes: 5
Maximum Delta S per Pass: 0.02
2. Click the OK button
Adding a Frequency Sweep
To add a frequency sweep:
1. Select the menu item HFSS > Analysis Setup > Add Sweep
1. Select Solution Setup: Setup1
2. Click the OK button
2. Edit Sweep Window:
1. Sweep Type:: Fast
2. Frequency Setup Type:: Linear Count
Start: 3.4GHz
Stop:: 4.0GHz
Count:: 1001
Save Fields: Checked
3. Click the OK button
Ansoft High Frequency Structure Simulator v10 User’s Guide
6.1-9
6.1
Save Project
To save the project:
1. In an Ansoft HFSS window, select the menu item File > Save As.
2. From the Save As window, type the Filename: hfss_magic_t
3. Click the Save button
Analyze
Model Validation
To validate the model:
1. Select the menu item HFSS > Validation Check
2. Click the Close button
Note: To view any errors or warning messages, use the Message
Manager.
Analyze
To start the solution process:
1. Select the menu item HFSS > Analyze
Ansoft High Frequency Structure Simulator v10 User’s Guide
6.1-10
6.1
Solution Data
To view the Solution Data:
1. Select the menu item HFSS > Results > Solution Data
To view the Profile:
1. Click the Profile Tab.
To view the Convergence:
1. Click the Convergence Tab
Note: The default view is for convergence is Table.
Table Select
the Plot radio button to view a graphical representations of
the convergence data.
To view the Matrix Data:
1. Click the Matrix Data Tab
Note: To view a real-time update of the Matrix Data, set the
Simulation to Setup1, Last Adaptive
2. Click the Close button
Ansoft High Frequency Structure Simulator v10 User’s Guide
6.1-11
6.1
Create Reports
Create SS-Parameter Plot vs. Adaptive Pass
Note: If this report is created prior or during the solution process, a real-time
update of the results are displayed
To create a report:
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Modal S Parameters
2. Display Type: Rectangular
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: Adaptive1
2. Click the X tab
1. Use Primary Sweep:: Unchecked
2. Category: Variables
3. Quantity:: Pass
3. Click the Y tab
1. Category: S Parameter
2. Quantity: S(p1,p1), S(p1,p2), S(p1,p3), S(p1,p4)
3. Function: dB
4. Click the Add Trace button
4. Click the Done button
Ansoft High Frequency Structure Simulator v10 User’s Guide
6.1-12
6.1
Create SS-Parameter Plot
To create a report:
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Modal S Parameters
2. Display Type: Rectangular
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: Sweep1
2. Domain: Sweep
3. Click the Y tab
1. Category: S Parameter
2. Quantity: S(p1,p1), S(p1,p2), S(p1,p3), S(p1,p4)
3. Function: dB
4. Click the Add Trace button
4. Click the Done button
Ansoft High Frequency Structure Simulator v10 User’s Guide
6.1-13
6.1
Create Field Overlay
To select an object:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Arm
2. Click the OK button
3. Select the menu item HFSS > Fields > Fields > E > Mag_E
4. Create Field Plot Window
1. Solution: Setup1 : LastAdaptive
2. Quantity: Mag_E
3. In Volume: All
4. Click the Done button
To modify the attributes of a field plot:
1. Select the menu item HFSS > Fields > Modify Plot Attributes
2. Select Plot Folder Window:
1. Select: E Field
2. Click the OK button
3. E-Field Window:
1. Click the Plot tab
1. IsoValType: IsoValSurface
2. Click the Apply button.
4. Click the Close button
Field Animations
To Animate a Magnitude field plot:
1. Select the menu item View > Animate
2. In the Swept Variable tab, accept the defaults settings:
1. Swept variable: Phase
2. Start: 0deg
3. Stop: 180deg
4. Steps: 9
3. Click OK
Ansoft High Frequency Structure Simulator v10 User’s Guide
6.1-14
6.2
Example – Coaxial Connector
The Coaxial Connector
This example is intended to show you how to create, simulate, and analyze a
coaxial connector, using the Ansoft HFSS Design Environment.
Ansoft High Frequency Structure Simulator v10 User’s Guide
6.2-1
6.2
Example – Coaxial Connector
Ansoft HFSS Design Environment
The following features of the Ansoft HFSS Design Environment are used to
create this passive device model
3D Solid Modeling
Primitives: Cylinders, Polylines, Circles
Boolean Operations: Unite, Subtract, and Sweep
Boundaries/Excitations
Ports: Wave Ports and Terminal Lines
Analysis
Sweep:: Fast Frequency
Results
Cartesian plotting
Field Overlays:
3D Field Plots, Animations, CutCut-Planes
Ansoft High Frequency Structure Simulator v10 User’s Guide
6.2-2
6.2
Example – Coaxial Connector
Getting Started
Launching Ansoft HFSS
1.
To access Ansoft HFSS, click the Microsoft Start button, select Programs,
Programs and select
the Ansoft, HFSS 10 program group. Click HFSS 10.
10
Setting Tool Options
To set the tool options:
Note: In order to follow the steps outlined in this example, verify that the
following tool options are set :
1. Select the menu item Tools > Options > HFSS Options
2. HFSS Options Window:
1. Click the General tab
Use Wizards for data entry when creating new boundaries:: Checked
Duplicate boundaries with geometry:: Checked
2. Click the OK button
3. Select the menu item Tools > Options > 3D Modeler Options.
Options
4. 3D Modeler Options Window:
1. Click the Operation tab
Automatically cover closed polylines:: Checked
2. Click the Drawing tab
Edit property of new primitives:: Checked
3. Click the OK button
Ansoft High Frequency Structure Simulator v10 User’s Guide
6.2-3
6.2
Example – Coaxial Connector
Opening a New Project
To open a new project:
1. In an Ansoft HFSS window, click the On the Standard toolbar, or select
the menu item File > New.
2. From the Project menu, select Insert HFSS Design.
Set Solution Type
To set the solution type:
1. Select the menu item HFSS > Solution Type
2. Solution Type Window:
1. Choose Driven Terminal
2. Click the OK button
Ansoft High Frequency Structure Simulator v10 User’s Guide
6.2-4
6.2
Example – Coaxial Connector
Creating the 3D Model
Set Model Units
To set the units:
1. Select the menu item 3D Modeler > Units
2. Set Model Units:
1. Select Units: cm
2. Click the OK button
Set Default Material
To set the default material:
1. Using the 3D Modeler Materials toolbar, choose Select
2. Select Definition Window:
1. Type pec in the Search by Name field
2. Click the OK button
Ansoft High Frequency Structure Simulator v10 User’s Guide
6.2-5
6.2
Example – Coaxial Connector
Create the Conductor 1
To create the conductor
1. Select the menu item Draw > Cylinder
2. Using the coordinate entry fields, enter the cylinder position
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
3.
Using the coordinate entry fields, enter the radius:
dX: 0.152,
0.152 dY: 0.0,
0.0 dZ: 0.0,
0.0 Press the Enter key
4.
Using the coordinate entry fields, enter the height:
dX: 0.0,
0.0 dY: 0.0,
0.0 dZ: 1.448,
1.448 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Conductor1
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Or press the CTRL+D key
Create Offset Coordinate System
To create an offset Coordinate System:
1. Select the menu item 3D Modeler > Coordinate System > Create >
Relative CS > Offset
2.
Using the coordinate entry fields, enter the origin
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 1.448, Press the Enter key
Create a Section
To section the conductor
1. Select the menu item Edit > Select All Visible. Or press the CTRL+A key.
2. Select the menu item 3D Modeler > Surface > Section
3. Section Window
Section Plane: XY
Click the OK button
Ansoft High Frequency Structure Simulator v10 User’s Guide
6.2-6
6.2
Example – Coaxial Connector
Rename the Section
To set the name:
1. Select the menu item HFSS > List
2. From the Model tab, select the object named Section1
3. Click the Properties button
1. For the Value of Name type: Bend
2. Click the OK button
4. Click the Done button
Set Grid Plane
To set the grid plane:
1. Select the menu item 3D Modeler > Grid Plane > YZ
Create Conductor Bend
To create the bend:
1. Select the menu item Draw > Arc > Center Point
2. Using the coordinate entry fields, enter the vertex point:
X: 0.0,
0.0 Y: 0.4,
0.4 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the radial point:
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
4. Using the coordinate entry fields, enter the sweep arc length:
X: 0.0,
0.0 Y: 0.4,
0.4 Z: 0.4,
0.4 Press the Enter key
5. Using the mouse, right-click and select Done
6. Click the OK button when the Properties dialog appears
Sweep Bend:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Bend, Polyline1
2. Click the OK button
3. Select the menu item Draw > Sweep > Along Path
4. Sweep along path Window
Angle of twist: 0
Draft Angle: 0
Draft Type: Round
Click the OK button
Ansoft High Frequency Structure Simulator v10 User’s Guide
6.2-7
6.2
Example – Coaxial Connector
Set Grid Plane
To set the grid plane:
1. Select the menu item 3D Modeler > Grid Plane > XZ
Create Offset Coordinate System
To create an offset Coordinate System:
1. Select the menu item 3D Modeler > Coordinate System > Create >
Relative CS > Offset
2.
Using the coordinate entry fields, enter the origin
X: 0.0,
0.0 Y: 0.4,
0.4 Z: 0.4, Press the Enter key
Create the Conductor 2
To create the conductor
1. Select the menu item Draw > Cylinder
2. Using the coordinate entry fields, enter the cylinder position
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the radius:
dX: 0.152,
0.152 dY: 0.0,
0.0 dZ: 0.0,
0.0 Press the Enter key
4. Using the coordinate entry fields, enter the height:
dX: 0.0,
0.0 dY: 0.436,
0.436 dZ: 0.0,
0.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Conductor2
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Create Offset Coordinate System
To create an offset Coordinate System:
1. Select the menu item 3D Modeler > Coordinate System > Create >
Relative CS > Offset
2.
Using the coordinate entry fields, enter the origin
X: 0.0,
0.0 Y: 0.436,
0.436 Z: 0.0,
0.0 Press the Enter key
Ansoft High Frequency Structure Simulator v10 User’s Guide
6.2-8
6.2
Example – Coaxial Connector
Create the Conductor 3
To create the conductor
1. Select the menu item Draw > Cylinder
2. Using the coordinate entry fields, enter the cylinder position
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the radius:
dX: 0.225,
0.225 dY: 0.0,
0.0 dZ: 0.0,
0.0 Press the Enter key
4. Using the coordinate entry fields, enter the height:
dX: 0.0,
0.0 dY: 1.3,
1.3 dZ: 0.0,
0.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Conductor3
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Group the Conductors
To group the conductors:
1. Select the menu item Edit > Select All Visible. Or press the CTRL+A key.
2. Select the menu item, 3D Modeler > Boolean > Unite
To fit the view:
1. Select the menu item View > Fit All > Active View.
Set Default Material
To set the default material:
1. Using the 3D Modeler Materials toolbar, choose vacuum
Ansoft High Frequency Structure Simulator v10 User’s Guide
6.2-9
6.2
Example – Coaxial Connector
Create the Female End
To create the female end:
1. Select the menu item Draw > Cylinder
2. Using the coordinate entry fields, enter the cylinder position
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the radius:
dX: 0.511,
0.511 dY: 0.0,
0.0 dZ: 0.0,
0.0 Press the Enter key
4. Using the coordinate entry fields, enter the height:
dX: 0.0,
0.0 dY: 1.3,
1.3 dZ: 0.0,
0.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Female
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Create the Female Bend
To create the bend:
1. Select the menu item Draw > Cylinder
2. Using the coordinate entry fields, enter the cylinder position
X: 0.0, Y: 0.0, Z: 0.0, Press the Enter key
3. Using the coordinate entry fields, enter the radius:
dX:
dX: 0.351, dY:
dY: 0.0, dZ:
dZ: 0.0, Press the Enter key
4. Using the coordinate entry fields, enter the height:
dX:
dX: 0.0, dY:
dY: -1.236, dZ:
dZ: 0.0, Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: FemaleBend
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
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6.2
Example – Coaxial Connector
Set Working Coordinate System
To set the working coordinate system:
1. Select the menu item 3D Modeler > Coordinate System > Set Working CS
2. Select Coordinate System Window,
1. From the list, select the CS: Global
2. Click the Select button
Set Grid Plane
To set the grid plane:
1. Select the menu item 3D Modeler > Grid Plane > XY
Create the Male End
To create the male end:
1. Select the menu item Draw > Cylinder
2. Using the coordinate entry fields, enter the cylinder position
X: 0.0, Y: 0.0, Z: 0.0, Press the Enter key
3. Using the coordinate entry fields, enter the radius:
dX:
dX: 0.351, dY:
dY: 0.0, dZ:
dZ: 0.0, Press the Enter key
4. Using the coordinate entry fields, enter the height:
dX:
dX: 0.0, dY:
dY: 0.0, dZ:
dZ: 2.348, Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Male
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
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6.2
Example – Coaxial Connector
Group the Vacuum Objects
To unite the objects Female, FemaleBend and Male:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Female, FemaleBend,
FemaleBend, Male
2. Click the OK button
3. Select the menu item, 3D Modeler > Boolean > Unite
To fit the view:
1. Select the menu item View > Fit All > Active View.
Add New Material
To add a new material:
1. Using the 3D Modeler Materials toolbar, choose Select
2. From the Select Definition window, click the Add Material button
3. View/Edit Material Window:
1. For the Material Name type: My_Ring
2. For the Value of Relative Permittivity type: 3
3. Click the OK button
4. Click the OK button
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6.2
Example – Coaxial Connector
Create the Ring
To create the ring:
1. Select the menu item Draw > Cylinder
2. Using the coordinate entry fields, enter the cylinder position
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.736,
0.736 Press the Enter key
3. Using the coordinate entry fields, enter the radius:
dX: 0.511,
0.511 dY: 0.0,
0.0 dZ: 0.0,
0.0 Press the Enter key
4. Using the coordinate entry fields, enter the height:
dX: 0.0,
0.0 dY: 0.0,
0.0 dZ: 0.236,
0.236 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Ring
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Complete the Ring
To select the objects Ring and Male:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Ring, Female
2. Click the OK button
To complete the ring:
1. Select the menu item 3D Modeler > Boolean > Subtract
2. Subtract Window
Blank Parts: Ring
Tool Parts: Female
Clone tool objects before subtract: Checked
Click the OK button
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6.2
Example – Coaxial Connector
Add New Material
To add a new material:
1. Using the 3D Modeler Materials toolbar, choose Select
2. From the Select Definition window, click the Add Material button
3. View/Edit Material Window:
1. For the Material Name type: My_Teflon
2. For the Value of Relative Permittivity type: 2.1
3. Click the OK button
4. Click the OK button
Create the Male Teflon
To create the teflon:
teflon:
1. Select the menu item Draw > Cylinder
2. Using the coordinate entry fields, enter the cylinder position
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.46,
0.46 Press the Enter key
3. Using the coordinate entry fields, enter the radius:
dX: 0.511,
0.511 dY: 0.0,
0.0 dZ: 0.0,
0.0 Press the Enter key
4. Using the coordinate entry fields, enter the height:
dX: 0.0,
0.0 dY: 0.0,
0.0 dZ: 0.788,
0.788 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: MaleTeflon
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
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6.2-14
6.2
Example – Coaxial Connector
Create Wave Port Excitation 1
Note: To simplify the instructions, a 2D object will be created to represent the
port. This is not a requirement for defining ports. Graphical face selection can
be used as an alternative.
To create a circle that represents the port:
1. Select the menu item Draw > Circle
2. Using the coordinate entry fields, enter the center position
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the radius of the circle:
dX: 0.351,
0.351 dY: 0.0,
0.0 dZ: 0.0,
0.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: p1
3. Click the OK button
To select the object p1:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: p1
2. Click the OK button
Note:
Note You can also select the object from the Model Tree
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6.2-15
6.2
Example – Coaxial Connector
Create Wave Port Excitation 1 (Continued)
To assign wave port excitation
1. Select the menu item HFSS > Excitations > Assign > Wave Port
2. Wave Port : General
1. Name: p1,
p1
2. Click the Next button
3. Wave Port : Terminals
1. Number of Terminals: 1,
2. For T1,
T1 click the Undefined column and select New Line
3. Using the coordinate entry fields, enter the vector position
X: 0.351,
0.351 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
4. Using the coordinate entry fields, enter the vertex
dX: -0.199,
0.199 dY: 0.0,
0.0 dZ: 0.0,
0.0 Press the Enter key
5. Click the Next button
4. Wave Port : Differential Pairs
1. Click the Next button
5. Wave Port : Post Processing
1. Full Port Impedance: 50
6. Click the Finish button
Set Working Coordinate System
To set the working coordinate system:
1. Select the menu item 3D Modeler > Coordinate System > Set Working CS
2. Select Coordinate System Window,
1. From the list, select the CS: RelativeCS3
2. Click the Select button
Set Grid Plane
To set the grid plane:
1. Select the menu item 3D Modeler > Grid Plane > XZ
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6.2-16
6.2
Example – Coaxial Connector
Create Wave Port Excitation 2
Note: To simplify the instructions, a 2D object will be created to represent the
port. This is not a requirement for defining ports. Graphical face selection can
be used as an alternative.
To create a circle that represents the port:
1. Select the menu item Draw > Circle
2. Using the coordinate entry fields, enter the center position
X: 0.0,
0.0 Y: 1.3,
1.3 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the radius of the circle:
dX: 0.511,
0.511 dY: 0.0,
0.0 dZ: 0.0,
0.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: p2
3. Click the OK button
To select the object p2:
1. Select Object Dialog,
1. Select the objects named: p2
2. Click the OK button
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6.2
Example – Coaxial Connector
Create Wave Port Excitation 2 (Continued)
To assign wave port excitation
1. Select the menu item HFSS > Excitations > Assign > Wave Port
2. Wave Port : General
1. Name: p2,
p2
2. Click the Next button
3. Wave Port : Terminals
1. Number of Terminals: 1,
2. For T1,
T1 click the Undefined column and select New Line
3. Using the coordinate entry fields, enter the vector position
X: 0.511,
0.511 Y: 1.3,
1.3 Z: 0.0,
0.0 Press the Enter key
4. Using the coordinate entry fields, enter the vertex
dX: -0.286,
0.286 dY: 0.0,
0.0 dZ: 0.0,
0.0 Press the Enter key
5. Click the Next button
4. Wave Port : Differential Pairs
1. Click the Next button
5. Wave Port : Post Processing
1. Full Port Impedance : 50
2. Click the Finish button
Ansoft High Frequency Structure Simulator v10 User’s Guide
6.2-18
6.2
Example – Coaxial Connector
Create the Female Teflon
To create the Teflon:
1. Select the menu item Draw > Cylinder
2. Using the coordinate entry fields, enter the cylinder position
X: 0.0, Y: 0.0, Z: 0.0, Press the Enter key
3. Using the coordinate entry fields, enter the radius:
dX:
dX: 0.511, dY:
dY: 0.0, dZ:
dZ: 0.0, Press the Enter key
4. Using the coordinate entry fields, enter the height:
dX:
dX: 0.0, dY:
dY: -0.236, dZ:
dZ: 0.0, Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: FemaleTeflon
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Complete the Vacuum Object
To select the objects Female, MaleTeflon,
MaleTeflon, FemaleTeflon
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Female, MaleTeflon,
MaleTeflon, FemaleTeflon
2. Click the OK button
To complete the vacumm objects:
1. Select the menu item 3D Modeler > Boolean > Subtract
2. Subtract Window
Blank Parts: Female
Tool Parts: MaleTeflon,
MaleTeflon, FemaleTeflon
Clone tool objects before subtract: Checked
Click the OK button
Ansoft High Frequency Structure Simulator v10 User’s Guide
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6.2
Example – Coaxial Connector
Complete the Model
To complete the model:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Conductor1, Female, MaleTeflon,
MaleTeflon,
FemaleTeflon
2. Click the OK button
3. Select the menu item 3D Modeler > Boolean > Subtract
4. Subtract Window
Blank Parts: Female, FemaleTeflon,
FemaleTeflon, MaleTeflon
Tool Parts: Conductor1
Clone tool objects before subtract: Checked
Click the OK button
Boundary Display
To verify the boundary setup:
1. Select the menu item HFSS > Boundary Display (Solver View)
2. From the Solver View of Boundaries, toggle the Visibility check box for the
boundaries you wish to display.
Note: The background (Perfect Conductor) is displayed as the outer
boundary.
Note: The Perfect Conductors are displayed as the smetal boundary.
Note: Select the menu item, View > Visibility to hide all of the
geometry objects. This makes it easier to see the boundary
3. Click the Close button when you are finished
Ansoft High Frequency Structure Simulator v10 User’s Guide
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6.2
Example – Coaxial Connector
Analysis Setup
Creating an Analysis Setup
To create an analysis setup:
1. Select the menu item HFSS > Analysis Setup > Add Solution Setup
2. Solution Setup Window:
1. Click the General tab::
Solution Frequency:: 8.1GHz
Maximum Number of Passes: 10
Maximum Delta S: 0.02
2. Click the OK button
3. Click the Options tab::
Minimum Converged Passes: 2
4. Click the OK button
Adding a Frequency Sweep
To add a frequency sweep:
1. Select the menu item HFSS > Analysis Setup > Add Sweep
1. Select Solution Setup: Setup1
2. Click the OK button
2. Edit Sweep Window:
1. Sweep Type:: Fast
2. Frequency Setup Type:: Linear Count
Start: 0.1GHz
Stop:: 8.1GHz
Count:: 801
Save Fields: Checked
3. Click the OK button
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6.2
Example – Coaxial Connector
Save Project
To save the project:
1. In an Ansoft HFSS window, select the menu item File > Save As.
2. From the Save As window, type the Filename: hfss_coax
3. Click the Save button
Analyze
Model Validation
To validate the model:
1. Select the menu item HFSS > Validation Check
2. Click the Close button
Note: To view any errors or warning messages, use the Message
Manager.
Analyze
To start the solution process:
1. Select the menu item HFSS > Analyze
Ansoft High Frequency Structure Simulator v10 User’s Guide
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6.2
Example – Coaxial Connector
Solution Data
To view the Solution Data:
1. Select the menu item HFSS > Results > Solution Data
To view the Profile:
1. Click the Profile Tab.
To view the Convergence:
1. Click the Convergence Tab
Note: The default view is for convergence is Table.
Table Select
the Plot radio button to view a graphical representations of
the convergence data.
To view the Matrix Data:
1. Click the Matrix Data Tab
Note: To view a real-time update of the Matrix Data, set the
Simulation to Setup1, Last Adaptive
2. Click the Close button
Ansoft High Frequency Structure Simulator v10 User’s Guide
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6.2
Example – Coaxial Connector
Create Reports
Create Terminal SS-Parameter Plot vs. Adaptive Pass
Note: If this report is created prior to or during the solution process, a
real-time update of the results are displayed
To create a report:
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Terminal S Parameters
2. Display Type: Rectangular
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: Adaptive1
2. Click the X tab
1. Use Primary Sweep:: Unchecked
2. Category: Variables
3. Quantity:: Pass
3. Click the Y tab
1. Category: Terminal S Parameter
2. Quantity: St(p1,p1), St(p1,p2),
3. Function: dB
4. Click the Add Trace button
4. Click the Done button
Ansoft High Frequency Structure Simulator v10 User’s Guide
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6.2
Example – Coaxial Connector
Create Terminal SS-Parameter Plot - Magnitude
To create a report:
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Terminal S Parameters
2. Display Type: Rectangular
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: Sweep1
2. Domain: Sweep
3. Click the Y tab
1. Category: Terminal S Parameter
2. Quantity: St(p1,p1), St(p1,p2),
3. Function: dB
4. Click the Add Trace button
4. Click the Done button
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6.2
Example – Coaxial Connector
Create Terminal SS-Parameter Plot - Phase
To create a report:
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Terminal S Parameters
2. Display Type: Rectangular
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: Sweep1
2. Domain: Sweep
3. Click the Y tab
1. Category: Terminal S Parameter
2. Quantity: St(p1,p1), St(p1,p2),
3. Function: ang_deg
4. Click the Add Trace button
4. Click the Done button
Ansoft High Frequency Structure Simulator v10 User’s Guide
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6.2
Example – Coaxial Connector
Field Overlays
Create Field Overlay
To create a field plot:
1. Select the Global YZ Plane
1. Using the Model Tree, expand Planes
2. Select Global:YZ
2. Select the menu item HFSS > Fields > Fields > E > Mag_E
3. Create Field Plot Window
1. Solution: Setup1 : LastAdaptive
2. Quantity: Mag_E
3. In Volume: All
4. Click the Done button
To modify a Magnitude field plot:
1. Select the menu item HFSS > Fields > Modify Plot Attributes
2. Select Plot Folder Window:
1. Select: E Field
2. Click the OK button
3. E-Field Window:
1. Click the Scale tab
1. Select Use Limits
2. Min: 1.0
3. Max: 1000.0
4. Scale: Log
2. Click the Close button
Ansoft High Frequency Structure Simulator v10 User’s Guide
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6.2
Example – Coaxial Connector
Edit Sources
To Modify a Terminal excitation:
1. Select the menu item HFSS > Fields > Edit Sources
2. Select p2:T1 from the Edit Sources window
Check the Terminated box
3. Click the OK button
To Select the Electric Field plot:
1. Expand the Project tree
2. Expand the Field Overlays
3. Click on the E Field or Mag_E1 to
display the field plot
Field Animations
To Animate a Magnitude field plot:
1. Select the menu item View > Animate
2. In the Swept Variable tab, accept defaults settings:
1. Swept variable: Phase
2. Start: 0deg
3. Stop: 180deg
4. Steps: 9
3. Click the Close button
Ansoft High Frequency Structure Simulator v10 User’s Guide
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6.3
Example – 180° Ring Hybrid
The 180° Ring Hybrid
This example is intended to show you how to create, simulate, and analyze a ring
hybrid, using Ansoft HFSS.
Ansoft High Frequency Structure Simulator v10 User’s Guide
6.3-1
6.3
Example – 180° Ring Hybrid
Getting Started
Launching Ansoft HFSS
1.
To access Ansoft HFSS, click the Microsoft Start button, select Programs,
Programs and
select the Ansoft, HFSS 10 program group. Click HFSS 10.
10
Setting Tool Options
To set the tool options:
Note: In order to follow the steps outlined in this example, verify that the
following tool options are set :
1. Select the menu item Tools > Options > HFSS Options
2. HFSS Options Window:
1. Click the General tab
Use Wizards for data entry when creating new boundaries:: Checked
Duplicate boundaries with geometry:: Checked
2. Click the OK button
3. Select the menu item Tools > Options > 3D Modeler Options.
Options
4. 3D Modeler Options Window:
1. Click the Operation tab
Automatically cover closed polylines:: Checked
2. Click the Drawing tab
Edit property of new primitives:: Checked
3. Click the OK button
Ansoft High Frequency Structure Simulator v10 User’s Guide
6.3-2
6.3
Example – 180° Ring Hybrid
Opening a New Project
To open a new project:
1. In an Ansoft HFSS window, click the On the Standard toolbar, or select
the menu item File > New.
2. From the Project menu, select Insert HFSS Design.
Set Solution Type
To set the solution type:
1. Select the menu item HFSS > Solution Type
2. Solution Type Window:
1. Choose Driven Terminal
2. Click the OK button
Ansoft High Frequency Structure Simulator v10 User’s Guide
6.3-3
6.3
Example – 180° Ring Hybrid
Creating the 3D Model
Set Model Units
To set the units:
1. Select the menu item 3D Modeler > Units
2. Set Model Units:
1. Select Units: mm
2. Click the OK button
Set Default Material
To set the default material:
1. Using the 3D Modeler Materials toolbar, choose Select
2. Select Definition Window:
1. Click the Add Material button
2. View/Edit Material Window:
1. For the Material Name type: My_Sub
2. For the Value of Relative Permittivity type: 2.33
3. For the Value of Dielectric Loss Tangent type: 4.29e4.29e-4
4. Click the OK button
3. Click the OK button
Ansoft High Frequency Structure Simulator v10 User’s Guide
6.3-4
6.3
Example – 180° Ring Hybrid
Create Substrate
To create the substrate:
1. Select the menu item Draw > Regular Polyhedron
2. Using the coordinate entry fields, enter the center position
X: 0.0,
0.0 Y: 0.0,
0.0 Z: -1.143,
1.143 Press the Enter key
3. Using the coordinate entry fields, enter the radius:
dX: 22.345mm/cos(30*pi/180), dY: 0.0,
0.0 dZ: 0.0,
0.0 Press the Enter key
4. Using the coordinate entry fields, enter the height:
dX: 0.0,
0.0 dY: 0.0,
0.0 dZ: 2.286,
2.286 Press the Enter key
Segment Number Window
Number of Segments: 6
Click the OK button
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Substrate
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Or press the CTRL+D key
Ansoft High Frequency Structure Simulator v10 User’s Guide
6.3-5
6.3
Example – 180° Ring Hybrid
Create Trace
To create the trace:
1. Select the menu item Draw > Rectangle
2. Using the coordinate entry fields, enter the rectangle position
X: -0.89154,
0.89154 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the rectangle:
dX: 1.78308,
1.78308 dY: 22.345,
22.345 dZ: 0.0,
0.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Trace
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Assign a Perfect E boundary to the Trace
To select the trace:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Trace
2. Click the OK button
To assign the Perfect E boundary
1. Select the menu item HFSS > Boundaries > Assign > Perfect E
2. Perfect E Boundary window
1. Name: PerfE_Trace
2. Click the OK button
Ansoft High Frequency Structure Simulator v10 User’s Guide
6.3-6
6.3
Example – 180° Ring Hybrid
Create Wave Port Excitation 1
Note: This structure requires 4 ports with 1 terminal lines per port. We could use
face selection to select the ends of the substrate that represent the port, define
terminal lines, assign excitation, and repeat for port2-4. Since we can duplicate
port definitions, it is more efficient to define a rectangle with the appropriate port
definition and copy it to the location of ports 2-4. The second method is
described here:
To set grid plane
1. Select the menu item 3D Modeler > Grid Plane > XZ
To sit the view
Select the menu item View > Modify Attributes > Orientation
Select Viewing Direction form the List Window
1. From the list select the view name: Right
2. Click the Apply button
3. Click the Close button
To create the rectangle graphically:
1. Select the menu item Draw > Rectangle
2. Using the mouse, position the active position indicator such that it snaps to
the vertex of the lower left corner of the substrate face. The shape of the
active position indicator will change to a square when it snaps to the vertex
3. Click the left mouse button to select this point as the start position.
4. Continued on next page…
Ansoft High Frequency Structure Simulator v10 User’s Guide
6.3-7
6.3
Example – 180° Ring Hybrid
Create Wave Port Excitation 1 (Continued)
4.
5.
Using the mouse, position the active position indicator such that it snaps to
the vertex of the upper right corner of the substrate face. The shape of the
active position indicator will change to a square when it snaps to the vertex
Click the left mouse button to set the opposite corner of the rectangle.
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Port
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Ansoft High Frequency Structure Simulator v10 User’s Guide
6.3-8
6.3
Example – 180° Ring Hybrid
Create Wave Port Excitation 1 (Continued)
To assign wave port excitation
1. Select the menu item HFSS > Excitations > Assign > Wave Port
2. Wave Port : General
1. Name: p1
2. Click the Next button
3. Wave Port : Terminals
1. Number of Terminals: 1, Click the Update button
2. For T1,
T1 click the Undefined column and select New Line
3. Using the coordinate entry fields, enter the vector position
X: 0.0,
0.0 Y: 22.345,
22.345 Z: -1.143,
1.143 Press the Enter key
4. Using the coordinate entry fields, enter the vertex
dX: 0.0,
0.0 dY: 0.0,
0.0 dZ: 1.143,
1.143 Press the Enter key
5. Click the Next button
4. Wave Port : Differential Pairs
1. Click the Next button
5. Wave Port : Post Processing
6. Click the Finish button
Wave Port Face
Ansoft High Frequency Structure Simulator v10 User’s Guide
Terminal Line
6.3-9
6.3
Example – 180° Ring Hybrid
Create the remaining Traces and Wave Ports
To select objects:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Trace, Port
2. Click the OK button
To duplicate the objects:
1. Select the menu item, Edit > Duplicate > Around Axis
2. Duplicate Around Axis Window
1. Axis: Z
2. Angle: 60deg
3. Total Number: 4
4. Click the OK button
Create Outer Ring
To set grid plane
1. Select the menu item 3D Modeler > Grid Plane > XY
To create the ring:
1. Select the menu item Draw > Circle
2. Using the coordinate entry fields, enter the position
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the radius:
dX: 11.795,
11.795 dY: 0.0,
0.0 dZ: 0.0,
0.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Outer
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit Drawing.
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6.3
Example – 180° Ring Hybrid
Group the Conductors
To group the conductors:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Trace, Trace_1, Trace_2, Trace_3, Outer
2. Click the OK button
3. Select the menu item, 3D Modeler > Boolean > Unite
To fit the view:
1. Select the menu item View > Fit Drawing.
Create Inner Ring
To create the ring:
1. Select the menu item Draw > Circle
2. Using the coordinate entry fields, enter the position
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the radius:
dX: 10.795,
10.795 dY: 0.0,
0.0 dZ: 0.0,
0.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Inner
3. Click the OK button
Select objects:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Trace, Inner
2. Click the OK button
3. Select the menu item, 3D Modeler > Boolean > Subtract
4. Subtract Window
1. Blank Parts: Trace
2. Tool Parts: Inner
3. Clone tool objects before subtracting:: Unchecked
4. Click the OK button
To fit the view:
1. Select the menu item View > Fit Drawing. Or press the CTRL+D key
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6.3
Example – 180° Ring Hybrid
Analysis Setup
Creating an Analysis Setup
To create an analysis setup:
1. Select the menu item HFSS > Analysis Setup > Add Solution Setup
2. Solution Setup Window:
1. Click the General tab::
Solution Frequency:: 4.0 GHz
Maximum Number of Passes: 20
Maximum Delta S: 0.02
2. Click the OK button
Adding a Frequency Sweep
To add a frequency sweep:
1. Select the menu item HFSS > Analysis Setup > Add Sweep
1. Select Solution Setup: Setup1
2. Click the OK button
2. Edit Sweep Window:
1. Sweep Type:: Fast
2. Frequency Setup Type:: Linear Step
Start: 2.0 GHz
Stop:: 7.0 GHz
Step:: 0.05 GHz
Save Fields: Checked
3. Click the OK button
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6.3
Example – 180° Ring Hybrid
Create Reports
Create Terminal SS-Parameter Plot vs. Adaptive Pass
Note: If this report is created prior or during the solution process, a real-time
update of the results are displayed
To create a report:
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Terminal S Parameters
2. Display Type: Rectangular
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: Adaptive1
2. Click the X tab
1. Use Primary Sweep:: Unchecked
2. Category: Variables
3. Quantity:: Pass
3. Click the Y tab
1. Category: Terminal S Parameter
2. Quantity: St(p1,p1), St(p1,p2), St(p1,p3), St(p1,p4)
3. Function: dB
4. Click the Add Trace button
4. Click the Done button
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Example – 180° Ring Hybrid
Create Terminal SS-Parameter Plot - Magnitude
To create a report:
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Terminal S Parameters
2. Display Type: Rectangular
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: Sweep1
2. Domain: Sweep
3. Click the Y tab
1. Category: Terminal S Parameter
2. Quantity: St(p1,p1), St(p1,p2), St(p1,p3), St(p1,p4)
3. Function: dB
4. Click the Add Trace button
4. Click the Done button
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Example – 180° Ring Hybrid
Save Project
To save the project:
1. In an Ansoft HFSS window, select the menu item File > Save As.
2. From the Save As window, type the Filename: hfss_ringhybrid
3. Click the Save button
Analyze
Model Validation
To validate the model:
1. Select the menu item HFSS > Validation Check
2. Click the Close button
Note: To view any errors or warning messages, use the Message
Manager.
Analyze
To start the solution process:
1. Select the menu item HFSS > Analyze
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Example – 180° Ring Hybrid
Solution Data
To view the Solution Data:
1. Select the menu item HFSS > Results > Solution Data
To view the Profile:
1. Click the Profile Tab.
To view the Convergence:
1. Click the Convergence Tab
Note: The default view is for convergence is Table.
Table Select
the Plot radio button to view a graphical representations of
the convergence data.
To view the Matrix Data:
1. Click the Matrix Data Tab
Note: To view a real-time update of the Matrix Data, set the
Simulation to Setup1, Last Adaptive
2. Click the Close button
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Example – 180° Ring Hybrid
Terminal SS-Parameter Plot vs. Adaptive Pass
Terminal SS-Parameter Plot - Magnitude
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6.4
Example – Coaxial Stub Resonator
The Coaxial Stub Resonator
This example is intended to show you how to create, simulate, and optimize a
coaxial stub resonator, using the Ansoft HFSS Design Environment.
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6.4
Example – Coaxial Stub Resonator
Ansoft HFSS Design Environment
The following features of the Ansoft HFSS Design Environment are used to
create this passive device model:
3D Solid Modeling
Primitives: Cylinders
Boolean: Union
Duplicate: Around Axis
Boundaries/Excitations
Excitations: Wave Ports
Analysis
Sweep: Fast Frequency
Optimization
Parametrics Setup
Optimetrics Setup
Results
Data: Tabular
Plotting: Cartesian
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Example – Coaxial Stub Resonator
Getting Started
Launching Ansoft HFSS
1.
To access Ansoft HFSS, click the Microsoft Start button, select Programs,
Programs and select
the Ansoft, HFSS 10 program group. Click HFSS 10.
10
Setting Tool Options
To set the tool options:
Note: In order to follow the steps outlined in this example, verify that the
following tool options are set :
1. Select the menu item Tools > Options > HFSS Options
2. HFSS Options Window:
1. Click the General tab
Use Wizards for data entry when creating new boundaries:: Checked
Duplicate boundaries with geometry:: Checked
2. Click the OK button
3. Select the menu item Tools > Options > 3D Modeler Options.
Options
4. 3D Modeler Options Window:
1. Click the Operation tab
Automatically cover closed polylines:: Checked
2. Click the Drawing tab
Edit property of new primitives:: Checked
3. Click the OK button
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Example – Coaxial Stub Resonator
Opening a New Project
To open a new project:
1. In an Ansoft HFSS window, click the On the Standard toolbar, or select
the menu item File > New.
2. From the Project menu, select Insert HFSS Design.
Set Solution Type
To set the solution type:
1. Select the menu item HFSS > Solution Type
2. Solution Type Window:
1. Choose Driven Terminal
2. Click the OK button
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Example – Coaxial Stub Resonator
Creating the 3D Model
Set Model Units
To set the units:
1. Select the menu item 3D Modeler > Units
2. Set Model Units:
1. Select Units: mm
2. Click the OK button
Set Default Material
To set the default material:
1. Using the 3D Modeler Materials toolbar, choose Select
2. Select Definition Window:
1. Type pec in the Search by Name field
2. Click the OK button
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Example – Coaxial Stub Resonator
Set Grid Plane
To set the grid plane:
1. Select the menu item 3D Modeler > Grid Plane > XZ
Create the Conductor 1
To create the conductor
1. Select the menu item Draw > Cylinder
2. Using the coordinate entry fields, enter the cylinder position
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the radius:
dX: 0.86,
0.86 dY: 0.0,
0.0 dZ: 0.0,
0.0 Press the Enter key
4. Using the coordinate entry fields, enter the height:
dX: 0.0,
0.0 dY: -6.0,
6.0 dZ: 0.0,
0.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window
2. For the Value of Name type: Conductor
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View. Or press the CTRL+D key
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Example – Coaxial Stub Resonator
Create the Stub
To create the stub
1. Select the menu item Draw > Cylinder
2. Using the coordinate entry fields, enter the cylinder position
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the radius:
dX: 0.86,
0.86 dY: 0.0,
0.0 dZ: 0.0,
0.0 Press the Enter key
4. Using the coordinate entry fields, enter the height:
dX: 0.0,
0.0 dY: 4.75,
4.75 dZ: 0.0,
0.0 Press the Enter key
To parameterize the object:
1. Select the Command tab from the Properties window
2. For Height,
Height type: L, Click the Tab key to accept
Add Variable L: 4.75mm,
4.75mm Click the OK button
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Stub
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Set Default Material
To set the default material:
1. Using the 3D Modeler Materials toolbar, choose vacuum
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Example – Coaxial Stub Resonator
Create the Body
To create the body
1. Select the menu item Draw > Cylinder
2. Using the coordinate entry fields, enter the cylinder position
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the radius:
dX: 2.0,
2.0 dY: 0.0,
0.0 dZ: 0.0,
0.0 Press the Enter key
4. Using the coordinate entry fields, enter the height:
dX: 0.0,
0.0 dY: -6.0,
6.0 dZ: 0.0,
0.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Body
3. Click the OK button
Create Wave Port Excitation 1
Note: To simplify the instructions, a 2D object will be created to represent the
port. This is not a requirement for defining ports. Graphical face selection can
be used as an alternative.
To create a circle that represents the port:
1. Select the menu item Draw > Circle
2. Using the coordinate entry fields, enter the center position
X: 0.0,
0.0 Y: -6.0,
6.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the radius of the circle:
dX: 2.0,
2.0 dY: 0.0,
0.0 dZ: 0.0,
0.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: p1
3. Click the OK button
To select the object p1:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: p1
2. Click the OK button
Note:
Note You can also select the object from the Model Tree
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Example – Coaxial Stub Resonator
Create Wave Port Excitation 1 (Continued)
To assign wave port excitation
1. Select the menu item HFSS > Excitations > Assign > Wave Port
2. Wave Port : General
1. Name: p1,
p1
2. Click the Next button
3. Wave Port : Terminals
1. Number of Terminals: 1,
2. For T1,
T1 click the Undefined column and select New Line
3. Using the coordinate entry fields, enter the vector position
X: 2.0,
2.0 Y: -6.0,
6.0 Z: 0.0,
0.0 Press the Enter key
4. Using the coordinate entry fields, enter the vertex
dX: -1.14,
1.14 dY: 0.0,
0.0 dZ: 0.0,
0.0 Press the Enter key
5. Click the Next button
4. Wave Port : Differential Pairs
1. Click the Next button
5. Wave Port : Post Processing
1. Full Port Impedance: 50
6. Click the Finish button
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Example – Coaxial Stub Resonator
Create Port 2 Arm
To select the objects Conductor, Body, & p1:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Body, Conductor, p1
Note: Use the Ctrl + Left mouse button to select multiple objects
2. Click the OK button
To create the port 2 arm:
1. Select the menu item, Edit > Duplicate > Around Axis.
1. Axis: X
2. Angle: -90
90
3. Total Number: 2
4. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Create Stub Body
To select the objects Body:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Body
2. Click the OK button
To create the stub body:
1. Select the menu Select the menu item, Edit > Duplicate > Around Axis.
1. Axis: X
2. Angle: 180
3. Total Number: 2
4. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
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Example – Coaxial Stub Resonator
Group the Body Objects
To select the objects Body, Body_1, Body_2:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Body, Body_1, Body_2
2. Click the OK button
3. Select the menu item, 3D Modeler > Boolean > Unite
To fit the view:
1. Select the menu item View > Fit All > Active View.
Group the Conductor & Stub Objects
To select the objects Conductor, Conductor_1, Stub:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Conductor, Conductor_1, Stub
2. Click the OK button
3. Select the menu item, 3D Modeler > Boolean > Unite
To fit the view:
1. Select the menu item View > Fit All > Active View.
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Example – Coaxial Stub Resonator
Boundary Display
To verify the boundary setup:
1. Select the menu item HFSS > Boundary Display (Solver View)
2. From the Solver View of Boundaries, toggle the Visibility check box for the
boundaries you wish to display.
Note: The background (Perfect Conductor) is displayed as the outer
boundary.
Note: The Perfect Conductors are displayed as the smetal boundary.
Note: Select the menu item, View > Visibility to hide all of the
geometry objects. This makes it easier to see the boundary
3. Click the Close button when you are finished
Mesh Operations
To select the object Body
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Body
2. Click the OK button
To create a mesh operation:
1. Select the menu item HFSS > Mesh Operations > Assign > Inside
Selection > Length based
2.
Element Length Based Refinement Window:
1. Name:: Body_Mesh
2. Restrict Length of Elements:: Unchecked
3. Restrict the Number of Elements: Checked
1. Maximum Number of Elements: 2000
4. Click the OK button
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Example – Coaxial Stub Resonator
Analysis Setup
Creating an Analysis Setup
To create an analysis setup:
1. Select the menu item HFSS > Analysis Setup > Add Solution Setup
2. Solution Setup Window:
1. Click the General tab::
Solution Frequency:: 13.0 GHz
Maximum Number of Passes: 10
Maximum Delta S: 0.02
2. Click the OK button
Adding a Frequency Sweep
To add a frequency sweep:
1. Select the menu item HFSS > Analysis Setup > Add Sweep
1. Select Solution Setup: Setup1
2. Click the OK button
2. Edit Sweep Window:
1. Sweep Type:: Fast
2. Frequency Setup Type:: Linear Step
Start: 5.0 GHz
Stop:: 20.0 GHz
Step:: 0.01 GHz
Save Fields: Checked
3. Click the OK button
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Example – Coaxial Stub Resonator
Create Terminal SS-Parameter Plot - Magnitude
To create a report:
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Terminal S Parameters
2. Display Type: Rectangular Plot
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: Sweep1
2. Domain: Sweep
3. Click the Y tab
1. Category: Terminal S Parameter
2. Quantity: St(p1,p1), St(p1,p2),
3. Function: dB
4. Click the Add Trace button
4. Click the Done button
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Example – Coaxial Stub Resonator
Save Project
To save the project:
1. In an Ansoft HFSS window, select the menu item File > Save As.
2. From the Save As window, type the Filename: hfss_stub_resonator
3. Click the Save button
Analyze
Model Validation
To validate the model:
1. Select the menu item HFSS > Validation Check
2. Click the Close button
Note: To view any errors or warning messages, use the Message
Manager.
Analyze
To start the solution process:
1. Select the menu item HFSS > Analyze
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Example – Coaxial Stub Resonator
Solution Data
To view the Solution Data:
1. Select the menu item HFSS > Results > Solution Data
To view the Profile:
1. Click the Profile Tab.
To view the Convergence:
1. Click the Convergence Tab
Note: The default view is for convergence is Table.
Table Select
the Plot radio button to view a graphical representations of
the convergence data.
To view the Matrix Data:
1. Click the Matrix Data Tab
Note: To view a real-time update of the Matrix Data, set the
Simulation to Setup1, Last Adaptive
2. Click the Close button
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6.4
Example – Coaxial Stub Resonator
Data Markers
The plot we created prior to the simulation will automatically be updated when the
analysis completes. The xy plot should currently be displayed. If it is not, select
the menu item Window > XY Plot1 to switch to the plot display
Mark All Traces
1. Select the menu item Report 2D > Mark All Traces
2. Click the Min button
3. When you are finished, select the menu item Report 2D > Mark All Traces
to remove the marker.
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6.4
Example – Coaxial Stub Resonator
Optimetrics Setup – Parametric Sweep
During the design of a microwave device, it is common practice to develop
design trends based on swept parameters. Ansoft HFSS with Optimetrics
Parametric Sweep can automatically create these design curves.
Add a Parametric Sweep
1.
2.
Select the menu item HFSS > Optimetrics Analysis > Add Parametric
Setup Sweep Analysis Window:
1. Click the Sweep Definitions tab::
1. Click the Add button
2. Add/Edit Sweep Dialog
1. Select Variable: L
2. Select Linear Count
3. Start: 4.0mm
4. Stop: 5.5mm
5. Count: 5
6. Click the Add button
7. Click the OK button
2. Click the Options tab::
1. Save Fields and Mesh: Checked
3. Click the OK button
Analyze Parametric Sweep
To start the solution process:
1. Expand the Project Tree to display the items listed under Optimetrics
2. Right-click the mouse on ParametricSetup1 and choose Analyze
Optimetrics Results
To view the Optimetrics Results:
1. Select the menu item HFSS > Optimetrics Analysis > Optimetrics Results
2. Select the Profile Tab to view the solution progress for each setup.
3. Click the Close button when you are finished viewing the results
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Example – Coaxial Stub Resonator
Create Terminal SS-Parameter Plot – S12 at each L
To create a report:
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Terminal S Parameters
2. Display Type: Rectangular Plot
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: Sweep1
2. Domain: Sweep
3. Click the Sweeps tab
1. Select Sweep Design and Project variable values
4. Click the Y tab
1. Category: Terminal S Parameter
2. Quantity: St(p1,p2)
3. Function: dB
4. Click the Add Trace button
5. Click the Done button
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Example – Coaxial Stub Resonator
Optimetrics Setup – Optimization
The Parametric Sweep was useful for generating design curves. For this simple
design with only a single variable we could use the design curves to make
educated guesses at performance targets that are not contained in the
Parametric Sweep. Ansoft HFSS and Optimetrics with Optimization takes the
guess work out of achieving performance targets. To demonstrate this we will
target a minimum S12 at 13GHz. Since this device has a very high Q, we will
consider anything <= -40dB at 13GHz to be a minimum. From the Parametric
Sweep, we can see that the search range can be limited to the range 4.7-5.1mm.
Since we are only interested in obtaining an optimum solution for 13GHz, we will
add an additional Solution Setup that does not include the frequency sweep.
This will reduce the amount of simulation time required to achieve the
performance goal.
Add an Analysis Setup
To create an analysis setup:
1. Select the menu item HFSS > Analysis Setup > Add Solution Setup
2. Solution Setup Window:
1. Click the General tab::
Solution Frequency:: 13.0 GHz
Maximum Number of Passes: 10
Maximum Delta S per Pass: 0.02
2. Click the OK button
Define Optimization Design Variables
To Define Optimization Design Variable
1. Select the menu item HFSS > Design Properties
2. Click the Optimization radio button::
1. Name: L
2. Include: Checked
3. Min: 4.0 mm
4. Max: 5.5 mm
3. Click the OK button
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Example – Coaxial Stub Resonator
Add Optimization Setup
1.
2.
Select the menu item HFSS > Optimetrics Analysis > Add Optimization
Setup Optimization Window:
1. Click the Goals tab:
1. Optimizer: QuasiQuasi-Newton
2. Max. No. of Iterations: 10
3. Click the Add button
4. From the Solution Column, click on the Setup1:Last Adaptive and
select Setup2:LastAdaptive from the list of solutions
5. Click the Edit Calculation button
6. Setup Output Variables dialog:
1. Category: Terminal S Parameter
2. Quantity: St(p1,p2)
3. Function: mag
4. Click the Insert Quantity Into Expression button
5. Name: s21_mag
6. Click the Add button
7. Click the Done button
7. Condition: <=
8. Goal: 0.01
9. Weight:1
1
10. Acceptable Cost: 0
11. Click the Variables tab:
1. Min: 4.7 mm
2. Max: 5.1mm
12. Click the OK button
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Example – Coaxial Stub Resonator
Analyze Optimization
To start the solution process:
1. Expand the Project Tree to display the items listed under Optimetrics
2. Right-click the mouse on OptimizationSetup1 and choose Analyze
Optimetrics Results
To view the Optimetrics Results:
1. Select the menu item HFSS > Optimetrics Analysis > Optimetrics Results
2. Click the Close button when you are finished viewing the results
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Example – Coaxial Stub Resonator
Create Terminal SS-Parameter Plot of Optimum Result
Once the Optimization completes, the design will automatically be updated
with the Optimum value. To view the performance of the device versus
frequency will require you to analyze the HFSS project with the optimum
design value.
To analyze the optimum design
1. Select the menu item HFSS > Analyze
To view the plot
The existing XY Plot 1 will automatically be updated when the solution
completes.
To change to the XY Plot 1 window, select the menu item Window > XY
Plot 1.
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6.5
Example – Wave Ports
Microstrip Wave Port
This example is intended to show you how wave port size can influence the
results of any simulation using the Ansoft HFSS Version 10 Design Environment.
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6.5
Example – Wave Ports
Ansoft Design Environment
The following features of the Ansoft HFSS Design Environment are used to
create this passive device model
3D Solid Modeling
Primitives: Boxes, Rectangle
Boolean Operations: Duplicate Along Line
Boundary/Excitation
Ports: Wave Ports and Integration Lines
Analysis
Solution: Ports Only
Sweep: Interpolating
Results
Cartesian plotting
Fields Overlays
Port Field Display
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6.5
Example – Wave Ports
Getting Started
Launching Ansoft HFSS
1.
To access Ansoft HFSS, click the Microsoft Start button, select Programs,
Programs and
select the Ansoft, HFSS 10 program group. Click HFSS 10.
10
Setting Tool Options
To set the tool options:
Note: In order to follow the steps outlined in this example, verify that the
following tool options are set :
1. Select the menu item Tools > Options > HFSS Options
2. HFSS Options Window:
1. Click the General tab
Use Wizards for data entry when creating new boundaries:: Checked
Duplicate boundaries with geometry:: Checked
2. Click the OK button
3. Select the menu item Tools > Options > 3D Modeler Options.
Options
4. 3D Modeler Options Window:
1. Click the Operation tab
Automatically cover closed polylines:: Checked
2. Click the Drawing tab
Edit property of new primitives:: Checked
3. Click the OK button
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6.5
Example – Wave Ports
Design Review
Generally speaking when we assign a wave port to a microstrip line, or any
quasi-TEM line, we need to include some area around the actual transmission
line. The big question is, “how much area?”
Below you will see the cross section of a simple microstrip line with naming
conventions shown.
~5w
>4h
w
h
As a rule of thumb, we typically create a 2D rectangle to represent the wave port
stimulus for this type of structure. The dimensions of the rectangle are roughly
five times the width of the transmission line by four times the height of the
substrate.
REMEMBER: These are only guidelines !!!
The height of the port will be affected by the permittivity of the substrate. The
higher the permittivity, the less the fields will propagate in the air, and the shorter
the port can be made.
The width of the port will affect the port impedance and
propagating modes. The narrower the width (image on
right), the more the fields will couple to the side walls of
the port. This effect may not be physical. The wider the
port, the greater chance that a higher frequency
waveguide mode can propagate.
This example will explore this last phenomenon.
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Example – Wave Ports
Opening a New Project
To open a new project:
In an Ansoft HFSS window, click the On the Standard toolbar, or select
the menu item File > New.
From the Project menu, select Insert HFSS Design.
Set Solution Type
To set the solution type:
Select the menu item HFSS > Solution Type
Solution Type Window:
Choose Driven Modal
Click the OK button
Set Model Units
To set the units:
Select the menu item 3D Modeler > Units
Set Model Units:
Select Units: mil
Click the OK button
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Example – Wave Ports
Add New Material
To add a new material:
1. Using the 3D Modeler Materials toolbar, choose Select
2. From the Select Definition window, click the Add Material button
3. View/Edit Material Window:
1. Material Name: My_Rogers
2. Relative Permittivity: 3.38
3. Click the OK button
4. Click the OK button
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Example – Wave Ports
Create Substrate
To create the substrate:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: 0.0,
0.0 Y: -400.0,
400.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the box:
dX: 200.0,
200.0 dY: 800.0,
800.0 dZ: 8.0,
8.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Substrate
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Set Default Material
To set the default material:
1. Using the 3D Modeler Materials toolbar, choose Select
2. Select Definition Window:
1. Type pec in the Search by Name field
2. Click the OK button
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Example – Wave Ports
Create Trace
To create the trace:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: 0.0,
0.0 Y: -9.25,
9.25 Z: 8.0,
8.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the box:
dX: 200.0,
200.0 dY: 18.5,
18.5 dZ: 1.4,
1.4 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Trace
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Create Ground
To create the ground:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: 0.0,
0.0 Y: -400.0,
400.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the box:
dX: 200.0,
200.0 dY: 800.0,
800.0 dZ: -1.4,
1.4 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Ground
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
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Example – Wave Ports
Set Default Material
To set the default material:
1. Using the 3D Modeler Materials toolbar, choose vacuum
Create Air
To create the Air:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: 0.0,
0.0 Y: -400.0,
400.0 Z: -1.4,
1.4 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the box:
dX: 200.0,
200.0 dY: 800.0,
800.0 dZ: 200.0,
200.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Air
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Create Radiation Boundary
To select the object Air:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Air
2. Click the OK button
To create a radiation boundary
1. Select the menu item HFSS > Boundaries > Assign > Radiation
2. Radiation Boundary Window
Name: Rad1
Click the OK button
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6.5
Example – Wave Ports
Set Grid Plane
To set the grid plane:
1. Select the menu item 3D Modeler > Grid Plane > YZ
Create the Wave Port
To create a rectangle that represents the port:
1. Select the menu item Draw > Rectangle
2. Using the coordinate entry fields, enter the center position
X:: 0.0,
0.0 Y:: -200.0,
200.0 Z:: 0.0, Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the rectangle:
dX:: 0.0,
0.0 dY:: 400.0,
400.0 dZ:: 50.0
50 0, Press the Enter key
To parameterize the object:
1. Select the Command tab from the Properties window
2. For Position,
Position type: 0mil, -Port_Width/2, 0mil,
0mil Click the Tab key to accept
Add Variable Port_Width:
Port_Width 400mil,
400mil Click the OK button
3. For YSize,
YSize type: Port_Width,
Port_Width Click the Tab key to accept
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Port1
3. Click the OK button
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6.5
Example – Wave Ports
Assign the Excitation 1
To select the object p1:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Port1
2. Click the OK button
To assign wave port excitation
1. Select the menu item HFSS > Excitations > Assign > Wave Port
2. Wave Port : General
1. Name: p1,
p1
2. Click the Next button
3. Wave Port : Modes
1. Number of Modes: 5
2. For Mode 1, click the None column and select New Line
3. Using the coordinate entry fields, enter the vector position
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0, Press the Enter key
4. Using the coordinate entry fields, enter the vertex
dX:: 0.0, dY:
dY: 0.0,
0.0 dZ: 8.0, Press the Enter key
For Mode 1, click the Zpi column and select Zpv
1. Click the Next button
4. Wave Port : Post Processing
1. Click the Next button
5. Click the Finish button
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Example – Wave Ports
Create Wave Port Excitation 2
To select the object Port1:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Port1
2. Click the OK button
To duplicate the port:
1. Select the menu item, Edit > Duplicate > Along Line
2. Using the coordinate entry fields, enter the first point of the duplicate vector
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the second point of the duplicate
vector
dX: 200.0,
200.0 dY: 0.0,
0.0 dZ: 0.0, Press the Enter key
4. Duplicate Along Line Windows
1. Total Number: 2
2. Click the OK button
5. Click the Done button
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Example – Wave Ports
Boundary Display
To verify the boundary setup:
1. Select the menu item HFSS > Boundary Display (Solver View)
2. From the Solver View of Boundaries, toggle the Visibility check box for the
boundaries you wish to display.
Note: The background (Perfect Conductor) is displayed as the outer
boundary.
Note: The Perfect Conductors are displayed as the smetal boundary.
Note: Select the menu item, View > Visibility to hide all of the
geometry objects. This makes it easier to see the boundary
3. Click the Close button when you are finished
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6.5
Example – Wave Ports
Analysis Setup
Creating an Analysis Setup
To create an analysis setup:
1. Select the menu item HFSS > Analysis Setup > Add Solution Setup
2. Solution Setup Window:
1. Click the General tab::
Solution Frequency:: 20GHz
2. Check Solve Ports Only 3. Click the OK button
Adding a Frequency Sweep
To add a frequency sweep:
1. Select the menu item HFSS > Analysis Setup > Add Sweep
1. Select Solution Setup: Setup1
2. Click the OK button
2. Edit Sweep Window:
1. Frequency Setup Type:: Linear Count
Start: 0.1GHz
Stop:: 50.1GHz
Count:: 81
3. Edit Setup Interpolation Basis Window:
1. Click the button for Setup Interpolation Basis
Sweep Type: Interpolating
Error Tolerance: 0.5%
Max Solutions: 20
2. Click the OK button
4. Click the OK button
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Example – Wave Ports
Save Project
To save the project:
1. In an Ansoft HFSS window, select the menu item File > Save As.
2. From the Save As window, type the Filename: hfss_waveports
3. Click the Save button
Analyze
Model Validation
To validate the model:
1. Select the menu item HFSS > Validation Check
2. Click the Close button
Note: To view any errors or warning messages, use the Message
Manager.
Analyze
To start the solution process:
1. Select the menu item HFSS > Analyze
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Example – Wave Ports
Solution Data
To view the Solution Data:
1. Select the menu item HFSS > Results > Solution Data
To view the Profile:
1. Click the Profile Tab.
To view the Matrix Data:
1. Click the Matrix Data Tab
2. Click the Close button
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6.5
Example – Wave Ports
Create Reports
Create Propagation Constant vs. Frequency
To Create a report:
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Modal S Parameters
2. Display Type: Rectangular
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: Sweep1
2. Click the Y tab
1. Domain: Sweep
2. Category: Gamma
3. Quantity: Gamma(p1:1),Gamma(p1:2), Gamma(p1:3),
Gamma(p1:4), Gamma(p1:5)
4. Function: im
5. Click the Add Trace button
3. Click the Done button
4. See next page for plot and discussion of results
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Example – Wave Ports
Create Reports
Discussion
What does this plot tell us?
Given the physical size of the wave port object that we created, the fundamental
mode (p2:1) is a quasi-TEM mode that propagates from DC on up.
This also shows that higher order modes can propagate (b>0) at a high enough
frequency. The second modes starts propagating at ~14 GHz.
Therefore, if we only needed to simulate up to 10 GHz, we wouldn’t need to size
our port any different, however, if we need to simulate up to 50 GHz, then we
need to resize our port to eliminate the higher order propagating modes.
The last part of the exercise will explore this.
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6.5
Example – Wave Ports
Field Pattern Plots
It might be illuminating to look at the field patterns at the port to discover which
modes are excited.
To display the Mode field patterns in the modeler:
1. From within the project manager, expand the section Port Field Display
2. Expand p1,
p1 and select Mode 2
1. The field pattern will be overlaid on the 3D model. From the plot
below, Mode 2 is clearly not a microstrip mode, but a TE10-like
waveguide mode.
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6.5
Example – Wave Ports
Optimetrics Setup – Parametric Sweep
Add a Parametric Sweep
1.
2.
Select the menu item HFSS > Optimetrics Analysis > Add Parametric
Setup Sweep Analysis Window:
1. Click the Sweep Definitions tab::
1. Click the Add button
2. Add/Edit Sweep Dialog
1. Variable: Port_Width
2. Select Linear Step
3. Start: 200mil
4. Stop: 600mil
5. Step: 100mil
6. Click the Add >> button
7. Click the OK button
2. Click the OK button
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6.5
Example – Wave Ports
Save Project
To save the project:
1. In an Ansoft HFSS window, select the menu item File > Save.
Analyze
Model Validation
To validate the model:
1. Select the menu item HFSS > Validation Check
2. Click the Close button
Note: To view any errors or warning messages, use the Message
Manager.
Analyze
To start the solution process:
1. Expand the Project Tree to display the items listed under Optimetrics
2. Right-click the mouse on ParametricSetup1 and choose Analyze
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Example – Wave Ports
Create Reports
Create Propagation Constant vs. Frequency vs. Port_Width
To Create a report:
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Modal S Parameters
2. Display Type: Rectangular
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: Sweep1
2. Click the Sweeps tab
1. Select the Sweep Design and Project Variable Values button
3. Click the Y tab
1. Domain: Sweep
2. Category: Gamma
3. Quantity: Gamma(p1:2),
4. Function: im
5. Click the Add Trace button
4. Click the Done button
5. See next page for plot and discussion of results
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Example – Wave Ports
Create Reports
Discussion
What does this plot tell us?
This shows that as we decrease the width of the port, the frequency at which the
higher order mode starts to propagate increases.
Therefore, by properly sizing the wave port, you can eliminate any higher order
propagating modes if you believe that they do not exist.
You need to use caution if you are simulating very high frequencies, i.e.,
millimeter wavelengths, as you may not be able to make the ports small enough
to eliminate these modes. You probably shouldn’t even try as the higher order
modes might represent real world effects.
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6.6
Example – Dielectric Resonator
Dielectric Resonator
This example is intended to show you how to create, simulate, and analyze a
shielded cylindrical dielectric resonator using the Ansoft HFSS Design
Environments eigen mode solver.
A dielectric resonator is intended to operate within a given frequency range and
the electromagnetic field in the vicinity of the resonator is expect to exhibit
behavior specific to the desired modes of operation. However, when employing
resonant circuits, frequencies of undesired modes may interfere with the desired
modes.
It is therefore of great practical importance to be able to determine the resonant
frequencies, mode patterns, energy and dissipated power of the modes existing
in a given structure, such that operation of and coupling to the resonator can be
determined.
Cavity
Dielectric
resonator
Substrate with ground plane
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Example – Dielectric Resonator
Ansoft HFSS Design Environment
The following features of the Ansoft HFSS Design Environment are used to
create this passive device model:
3D Solid Modeling
Primitives: Cylinders
Variables: Project and model variables
Materials/Boundaries/Excitations
Materials: Defining custom materials
Boundaries: Perfect E
Solution Setup
Parametric sweep
Results
Eigenmode Data – convergence of the individual modes
Formatting plots
Fields: E- & HH-Field
Fields: Plotting on custom cutcut-planes
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Example – Dielectric Resonator
Design Review
This example is taken from the book "Finite Element Software for Microwave
Engineering" by Tatsuo Itoh, Giuseppe Pelosi and Peter P. Silvester, 1996,
John Wiley & Sons ISBN 0-471-12636-5 (page 62 onwards)
The goal of this simulation is to determine how the resonant modes set up in
the dielectric resonator changes as the geometry around the resonator
changes. In particular a variation of the distance from the dielectric resonator
top to the cavity top will be examined.
There are two methods we could use to analyze this problem:
Method 1: Define e.g. a microstrip transfering in and out of the cavity and
define excitation of the microstrip. The microstrip will have a loading
effect on the cavity depending on location, termination etc. Therefore an
investigation using this approach will be dependent on the feed structure
and modes may be missed.
Method 2:
2 Use the Eigenmode solver to determine the natural
resonances of the cylindrical dielectric resonator alone.
To follow the procedure in the reference, we will use the second method. As
the eigenmode solver does not use ports we will only have to define the
geometry and the boundary conditions. We will solve for the first 6 modes
appearing in the structure.
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Example – Dielectric Resonator
Details of the model
The commonly used resonant modes in cylindrical dielectrics are denoted TE0,m,δ,
TM0,m,δ, and HEMn,m,δ, respectively, for transverse electric, transverse magnetic,
and hybrid mode. The subscripts m, n, and δ are the azimuthal, radial and axial
wavenumbers, respectively.
The dimensions in the model are as follows and a picture showing the
dimensions given below as well.
Hwall
Cavity
R
ε_0
Dielectric resonator
Substrate
6-15mm
15mm
1
h
5mm
D
10mm
ε_r
36
h_s
1mm
R
15mm
ε_s
9.6
R
Hwall
h
ε0
εr
εs
Hs
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6.6
Example – Dielectric Resonator
Getting Started
Launching Ansoft HFSS
1.
To access Ansoft HFSS, click the Microsoft Start button, select Programs,
Programs and select
the Ansoft, HFSS 10 program group. Click HFSS 10.
10
Setting Tool Options
To set the tool options:
Note: In order to follow the steps outlined in this example, verify that the
following tool options are set :
1. Select the menu item Tools > Options > HFSS Options
2. HFSS Options Window:
1. Click the General tab
Use Wizards for data entry when creating new boundaries:: Checked
Duplicate boundaries with geometry:: Checked
2. Click the OK button
3. Select the menu item Tools > Options > 3D Modeler Options.
Options
4. 3D Modeler Options Window:
1. Click the Operation tab
Automatically cover closed polylines:: Checked
2. Click the Drawing tab
Edit property of new primitives:: Checked
3. Click the OK button
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Example – Dielectric Resonator
Opening a New Project
To open a new project:
1. In an Ansoft HFSS window, click the On the Standard toolbar, or
select the menu item File > New.
2. From the Project menu, select Insert HFSS Design.
Set Solution Type
To set the solution type:
1. Select the menu item HFSS > Solution Type
2. Solution Type Window:
1. Choose Eigenmode
2. Click the OK button
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Example – Dielectric Resonator
Creating the 3D Model
Set Model Units
To set the units:
1. Select the menu item 3D Modeler > Units
2. Set Model Units:
1. Select Units: mm
2. Click the OK button
Set Default Material
To set the default material:
Using the 3D Modeler Materials toolbar, choose vacuum
Create the cavity
Create a cylinder
1. Select the cylinder icon from the 3D modeler toolbar
2. Using the coordinate entry fields, enter the base center
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
3. Using the 3D Modeler toolbar make sure that the base coordinate entry
plane is set to xy.
xy Then set the cavity radius in the x entry field and the
height in the z-entry field. Note: It is not yet possible to use parameters
directly in the coordinate entry field.
dX:: 15,
15 dY:: 0.0,
0.0 dZ:: 10, Press the Enter key
Parameterize the height of the cavity
1. In the ‘Height’ entry box write a parameter name called ‘Hwall
Hwall’.
Hwall
2. Upon hitting the Enter key HFSS will ask you for the value of the parameter
3. Write ’10mm
10mm’
10mm – do not forget the units!
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Cavity
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Example – Dielectric Resonator
To set the Wireframe view:
1. Select the Attribute tab from the Properties window.
2. Display Wireframe: Checked
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Or press the CTRL+D key
Create New Materials and Set Default Material
Create new materials:
1. Using the 3D Modeler Materials toolbar, choose Select
2. Click ‘Add
Add Material’-button.
Material
3. Set Material Name to subs
4. Set the dielectric permittivity, εr, to 9.6 and leave the rest with their defaults
5. Click ’OK
OK’
OK
6. Add new material called DielRes with εr=36
To set the default material:
1. You can now set default material by selecting subs in the list and clicking OK
Create the substrate
Create a cylinder
1. Select the cylinder icon from the 3D modeler toolbar
2. Using the coordinate entry fields, enter the base center
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
3. Set base coordinate entry plane to xy. Then set the radius in the x entry field
and the height in the z-entry field.
dX: 15,
15 dY: 0.0,
0.0 dZ: -1.0,
1.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Substrate
You can now set transparency and color to your likings
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Example – Dielectric Resonator
Set Default Material
Set the default material:
1. Using the 3D Modeler Materials toolbar select the material created previously
called DielRes.
DielRes
Create the Dielectric Resonator
Create Cylinder representing resonator
1. Select the cylinder icon from the 3D modeler toolbar
2. Using the coordinate entry fields, enter the base center
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
3. Set base coordinate entry plane to xy. Then set the radius in the x entry field
and the height in the z-entry field.
dX: 5.0,
5.0 dY: 0.0,
0.0 dZ: 5.0,
5.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: DielRes
You can now set transparency and color to your likings
Setting Boundary Conditions
We have know defined the complete model, the only thing missing before running the
analysis is what boundary condition should be applied to the other part of the cavity
and the substrate.
HFSS assigns per default ‘Perfect Electrical Conductor’ (PEC) to any boundary exposed
to the background. This default assignment can be overriden if you wanted to
enclose the resonator in e.g. a aluminum cavity. This would have an effect on the
quality factor and the resonant modes. How much influence we could easily
determine using the eigenmode solver.
However for this exercise we will just stick to the default behaviour of HFSS, and
therefore we will effectively enclose the resonator in perfectly conducting cavity.
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Example – Dielectric Resonator
Analysis Setup
Creating an Analysis Setup
To create an analysis setup:
1. Select the menu item HFSS > Analysis Setup > Add Solution Setup
2. Solution Setup Window:
1. Click the General tab::
Minimum Frequency:: 3 GHz
Number of Modes:: 6
Maximum Number of Passes: 14
Maximum Delta Frequency per Pass: 2.5%
2.5
2. Under the Options tab:
Minimum Converged Passes : 3
Save Project
To save the project:
1. In an Ansoft HFSS window, select the menu item File > Save As.
2. From the Save As window, type the Filename: hfss_diel_res
3. Click the Save button
Analyze
Model Validation
It is possible to check the validity of the model you have built before sending it off
to be solved. This can e.g. be extremely useful before starting a large simulation.
1. Select the menu item HFSS > Validation Check
2. Click the Close button
Note: To view any errors or warning messages, use the Message
Manager.
Analyze
To start the solution process:
1. Select the menu item HFSS > Analyze
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Example – Dielectric Resonator
Solution Data
To view the Solution Data:
1. Select the menu item HFSS > Results > Solution Data
To view the Profile (memory use, solution time and no. of
tetrahedra):
tetrahedra):
1. Click the Profile Tab.
To view the Convergence:
1. Click the Convergence Tab
Note: The default view is for convergence is Table.
Table Select
the Plot radio button to view a graphical representations of
the convergence data.
To view the Eigenmode Data:
1. Click the Eignemode Data Tab. You will notice that the
following modes has been found:
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Example – Dielectric Resonator
Solution Data (continued)
You will notice that some of the modes comes in pairs – they
are degenerate modes. You will also see this later in the
exercise when we plot the fields inside the structure.
Note: To view a real-time update of the Eigenmode Data, set
the Simulation to Setup1, Last Adaptive
2. Click the Close button
We will now view the convergence of the individual modes rather than looking at
the convergence through the HFSS convergence criteria, ∆f in percent.
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window:
1. Report Type: Eigenmode Parameters
2. Display Type: Rectangular
3. Click the OK button
3. Traces Window:
1. Solution: Setup1: Adaptive_1
2. Click the Y tab
3. Category: Eigen Modes
4. Quantity: Mode(1), Mode(2), .... Mode(6). You can use CTRL for
multiple select.
5. Function: Re
6. Click the Add Trace button
7. Click the Done button
4. The plot you now see we need to format at bit to make it more easily
readable.
1. Double click on the y-axis numbers. This will get you the following
dialogue:
2.
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6.6
Example – Dielectric Resonator
Solution Data (continued)
Click the Scaling-tab.
Scaling
3. Click the checkbox ‘Scientific
Scientific Notation’
Notation
4. Write e.g. ‘Resonant
Resonant Frequency [Hz]’
[Hz] in the ‘Label’ text field
Note: To view a real-time update of the Eigenmode Data, set
the Simulation to Setup1, Last Adaptive
2. Click the Close button
As you can see, the modes HFSS has found stays fairly constant in frequency
versus iteration number after pass number 7. It is also easily identified that mode
pair 5 & 6 as well as mode pair 1 & 2 are actually one and the same. The glitch in
mode 5 between adaptive pass 4 and 6 is caused by the fact that mode 5 is not
well represented by the mesh at pass no. 4. However, as mode 5 is degenerate
we could most likely have plotted the fields at adaptive pass 4 by looking at the
field distribution of mode 6 instead, and using our knowlegde that the fields of the
degenerate modes are orthogonal.
2.
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6.6
Example – Dielectric Resonator
Field Overlays
We will now take the opportunity to look at the eigenmodes that HFSS has found.
HFSS includes a number of different plotting techniques which will be explored in
this section.
Create Field Overlay
To create a field plot:
1. Select the Global:XZ-plane
in the model tree under the folder Planes.
Global:XZ
2. Select the menu item HFSS > Fields > Fields > E > Mag_E
3. Create Field Plot Window
1. Solution: Setup1 : LastAdaptive
2. Quantity: Mag_E
3. In Volume: All
4. Click the Done button
4. You will now see the distribution of the Magnitude of the E-field on the XZcross plane for the complete model.
Mode 1: Magnitude of EE-Field
6.
Note:
Note HFSS will be default display the first mode in the structure.
To change the mode excitation of the structure
1. Select the menu item HFSS > Fields > Edit Sources
2. Edit Sources window
1. Set source: EigenMode_1 to magnitude: 0 and phase: 0
2. Source: EigenMode_2 to magnitude: 1 and phase: 0
3. Click the OK button
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Example – Dielectric Resonator
Magnitude of E plots in the XZ-plane
The following is a plot of the different mode field distribution in the XZ-plane,
which has been created by modifying the source excitation.
Mode 1: Magnitude of EE-Field
Mode 2: Magnitude of EE-Field
Mode 3: Magnitude of EE-Field
Mode 4: Magnitude of EE-Field
Mode 5: Magnitude of EE-Field
Mode 6: Magnitude of EE-Field
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6.6
Example – Dielectric Resonator
Magnitude of H plots in the XZ-plane
The following is a plot of the different mode field distributions in the XZ-plane for
the H field.
Note:
Note The field distribution patters for the H-field will at the default excitation
(phase = 0) at times (depending on the setup) seemingly not provide any field –
i.e. the
Mode 1: Magnitude of HH-Field
Mode 2: Magnitude of HH-Field
Mode 3: Magnitude of HH-Field
Mode 4: Magnitude of HH-Field
Mode 5: Magnitude of HH-Field
Mode 6: Magnitude of HH-Field
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6.6
Example – Dielectric Resonator
Plotting Field Data on Custom Cut-plane
It is possible to plot the field data on a custom defined cutplane. We will do this in the
following:
1. Create a new coordinate system which contains the cross plane of interest.
1. Select 3D ModelerModeler->Coordinate SystemSystem->Create>Create->Relative CSCS->Both
2. Set origin to be at the center of the resonator by using the coordinate
entry field:
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 5.00 / 2,
2 Press the Enter key
3. Set the X-axis location
dX: 5.00,
5.00 / 2,
5.00 Y: 0.0,
0.0 Z: -5.00
2 Press the Enter key
4. Set the XY-plane (remember to select Absolute referencing on the
coordinate toolbar)
5.
6.
7.
X: 0.0,
0.0 Y: 5.0,
5.0 Z: 0.0 , Press the Enter key
You will now see a new coordinate system called RelativeCS1.
RelativeCS1 The cutplanes of this coordinate system can be selected in the Model Tree
under the tab called Planes.
Select RelativeCS1:XY
Select HFSS > Fields > Fields > H > Mag_H and accept the defaults
except setting Phase to 180deg. Do the same for Vector_H.
Vector_H
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6.6
Example – Dielectric Resonator
Optimetrics Setup – Parametric Sweep
We would now like to examine how the resonant frequencies changes as we
change the the heigh of the cavity, HWall. Ansoft HFSS with Optimetrics
Parametric Sweep can automatically create these design curves.
Since the structure already is parameterized with respect to HWall, we will only
need to create a parametric sweep. Afterwards we can then generate design trend
curves to see how the modes shift.
Note:
Note This exercise, will depending on the speed of your computer take quite
some time. It took approximately 3.5 hours to solve on a 2.2GHz machine using at
most 130Mb of RAM. Therefore if you want to follow this part of the exercise, you
may want to reserve yourself more time than what is alloted during the standard
Ansoft Training courses. Nevertheless, the exercise will give you some important
insight into how the parametric analysis works together with the eigenmode solver
in HFSS. Therefore, you may want to consider to
1. Reduce the Maximum number of adaptive passes used to 8
2. Reduce the number of HWall steps to 4 (using ‘Linear Count’ in the analysis
setup)
3. Reduce the number of modes solved for to 4 (the TE0,m,δ, TM0,m,δ, and HEM
modes + 1 degenerate)..
Add a Parametric Sweep
1.
2.
Select the menu item HFSS > Optimetrics Analysis > Add Parametric
Setup Sweep Analysis Window:
1. Click the Sweep Definitions tab::
1. Click the Add button
2. Add/Edit Sweep Dialog
1. Variable: HWall
2. Select Linear Step
3. Start: 6mm
4. Stop: 15mm
5. Step: 1mm
6. Click the Add >> button
7. Click the OK button
2. Click on the General tab::
1. Save Fields:: Checked
3. Click the OK button
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6.6
Example – Dielectric Resonator
Save Project
To save the project:
1. In an Ansoft HFSS window, select the menu item File > Save.
Analyze
To start the solution process:
1. Select the menu item HFSS -> Analyze
As previously mentioned this will take a couple of hours to solve depending
on your solution settings.
Create Reports
Create Mode plot vs. HWall
To Create a report:
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Eigenmode Paramters
2. Display Type: Rectangular
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: LastAdaptive
2. Click the Sweeps tab
1. Select the Sweep Design and Project Variable Values button,
to be able to look at the parametric sweeps and not only the
nominal design
2. In the table make sure HWall appears in the top of the Name
column
3. Click the Y tab
1. Category: Eigen Modes
2. Quantity: Mode(1), Mode(2), .... Mode(6).
3. Function: Re
4. Click the Add Trace button
4. Click the Done button
4. Results can be seen on the following page, together with results from the
reference stated on page 3.
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Example – Dielectric Resonator
Mode dependence on Hwall
Mode 4
Mode 3
Mode 2
Mode 1
Modes found by HFSS
Modes found by Itoh et al.
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6.6
Example – Dielectric Resonator
Parametric investigation of mode dependence on Hwall
From the mode investigations on the previous page it is apparent that the results
seems to qualitative the same. However ‘Mode 1’ which one would immediately
think represents the TM01δ-mode seems to flatten off towards4.92GHz rather than
rising to 5.72GHz at Hwall=15mm. This appears as a wrong result, but really is
not. Rather this is due to the fact that :
HFSS orders the modes such that the lowest resonant frequency always
will be Mode1, the second lowest resonant frequency will always be Mode2
etc. That is
fMode1 < fMode2 < fMode3 < .... < fMode[n]
Therefore to correlate the results we need to take this into consideration. We thus
see that
The TE01δ-mode is represented by Mode 4 upto HWall=12mm and thereafter
by Mode 3
The TM01δ-mode is represented by Mode 1 upto HWall=8mm. Upto 12mm by
Mode 3 and then finally by Mode 4 upto 16mm.
The hybrid mode, HEM, will be represented by Mode 3 upto HWall=8mm
and upwards by Mode 1 / Mode 2 (which again will be degenerate.
If we needed to determine the above without using a reference like Itoh, we
would need to look at field plots to determine what the different modes found by
HFSS represents. But as you have seen this is a fairly easy task simply but
plotting the E and / or H fields in a cross section or within either the complete
model volume or within specific parts of the model.
This concludes the exercise.
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Chapter 7.0
Chapter 7.0 – Filter Examples
7.1 – Bandpass Filter
7.2 – Bandstop Filter
Ansoft High Frequency Structure Simulator v10 User’s Guide
7.1
Example – Bandpass Filter
Bandpass Filter
This example is intended to show you how to create, simulate, and analyze a
bandpass filter using the Ansoft HFSS Design Environment.
Nominal Design:
Fcenter = 1.50 GHz
BW = 1 GHz
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7.1
Example – Bandpass Filter
Ansoft Design Environment
The following features of the Ansoft HFSS Design Environment are used to
create this passive device model
3D Solid Modeling
Primitives: Cylinders, Boxes
Boolean Operations: Duplicate Around Axis
Boundary/Excitation
Ports: Wave Ports and Terminal Lines
Analysis
Sweep: Fast Frequency
Results
Cartesian plotting
Fields Overlays
2D & 3D Field Plots
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7.1
Example – Bandpass Filter
Getting Started
Launching Ansoft HFSS
1.
To access Ansoft HFSS, click the Microsoft Start button, select Programs,
Programs and
select the Ansoft, HFSS 10 program group. Click HFSS 10.
10
Setting Tool Options
To set the tool options:
Note: In order to follow the steps outlined in this example, verify that the
following tool options are set :
1. Select the menu item Tools > Options > HFSS Options
2. HFSS Options Window:
1. Click the General tab
Use Wizards for data entry when creating new boundaries:: Checked
Duplicate boundaries with geometry:: Checked
2. Click the OK button
3. Select the menu item Tools > Options > 3D Modeler Options.
Options
4. 3D Modeler Options Window:
1. Click the Operation tab
Automatically cover closed polylines:: Checked
2. Click the Drawing tab
Edit property of new primitives:: Checked
3. Click the OK button
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7.1
Example – Bandpass Filter
Opening a New Project
To open a new project:
In an Ansoft HFSS window, click the On the Standard toolbar, or select
the menu item File > New.
From the Project menu, select Insert HFSS Design.
Set Solution Type
To set the solution type:
Select the menu item HFSS > Solution Type
Solution Type Window:
Choose Driven Terminal
Click the OK button
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7.1
Example – Bandpass Filter
Creating the 3D Model
Set Model Units
To set the units:
Select the menu item 3D Modeler > Units
Set Model Units:
Select Units: in
Click the OK button
Set Default Material
To set the default material:
Using the 3D Modeler Materials toolbar, choose vacuum
Create Body
To create body:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: -1.0,
1.0 Y: -1.7,
1.7 Z: -0.3125,
0.3125 Press the Enter key
2. Using the coordinate entry fields, enter the opposite corner of the box
dX: 2.0,
2.0 dY: 3.4,
3.4 dZ: 0.0,
0.0 Press the Enter key
1. Using the coordinate entry fields, enter the box hieght
dX: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.625,
0.625 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: air
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View. Or press the CTRL+D key
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7.1-5
7.1
Example – Bandpass Filter
Create coax outer diameter
To create the outer diameter:
1. From the Drawing Plane toolbar, change the active plane to YZ.
YZ
2. Select the menu item Draw > Cylinder
3. Using the coordinate entry fields, enter the center position
X: 1.0,
1.0 Y: -0.9,
0.9 Z: 0.0,
0.0 Press the Enter key
4. Using the coordinate entry fields, enter the radius of the cylinder
dX: 0.0,
0.0 dY: 0.14,
0.14 dZ: 0.0,
0.0 Press the Enter key
5. Using the coordinate entry fields, enter the height of the cylinder
dX: 0.75,
0.75 dY: 0.0,
0.0 dZ: 0.0,
0.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: feed1
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Set Default Material
To set the default material:
1. Using the 3D Modeler Materials toolbar, choose Select
2. Select Definition Window:
1. Type pec in the Search by Name field
2. Click the OK button
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7.1
Example – Bandpass Filter
Create coax inner diameter
To create the inner diameter:
1. Select the menu item Draw > Cylinder
2. Using the coordinate entry fields, enter the center position
X: 1.0,
1.0 Y: -0.9,
0.9 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the radius of the cylinder
dX: 0.0,
0.0 dY: 0.06,
0.06 dZ: 0.0,
0.0 Press the Enter key
4. Using the coordinate entry fields, enter the height of the cylinder
dX: 0.75,
0.75 dY: 0.0,
0.0 dZ: 0.0,
0.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: feedin1
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Create the coax feed probe
To create the coax feed probe:
1. Select the menu item Draw > Cylinder
2. Using the coordinate entry fields, enter the center position
X: 1.0,
1.0 Y: -0.9,
0.9 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the radius of the cylinder
dX: 0.0,
0.0 dY: 0.06,
0.06 dZ: 0.0,
0.0 Press the Enter key
4. Using the coordinate entry fields, enter the height of the cylinder
dX: -0.15,
0.15 dY: 0.0,
0.0 dZ: 0.0,
0.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: feedprobe1
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
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7.1
Example – Bandpass Filter
Create the resonators
To create l1:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: 0.85,
0.85 Y: -0.9625,
0.9625 Z: -0.03,
0.03 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the box
dX: -1.7,
1.7 dY: 0.125,
0.125 dZ: 0.06,
0.06 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: l1
3. Click the OK button
To create l2:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: -1.0,
1.0 Y: -0.75,
0.75 Z: -0.03,
0.03 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the box
dX: 1.818,
1.818 dY: 0.125,
0.125 dZ: 0.06,
0.06 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: l2
3. Click the OK button
To create l3:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: 1.0,
1.0 Y: -0.48,
0.48 Z: -0.03,
0.03 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the box
dX: -1.818,
1.818 dY: 0.125,
0.125 dZ: 0.06,
0.06 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: l3
3. Click the OK button
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7.1
Example – Bandpass Filter
Create the resonators (Continued)
To create l4:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: -1.0,
1.0 Y: -0.2,
0.2 Z: -0.03,
0.03 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the box
dX: 1.818,
1.818 dY: 0.125,
0.125 dZ: 0.06,
0.06 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: l4
3. Click the OK button
Create the Wave port
Picking the port face:
1. Select the menu item Edit > Select > Faces
2. Graphically select the outer face of the coax line at X=1.75in
To assign the wave port excitation:
1. Select the menu item HFSS > Excitations > Assign > Wave Port
2. Wave Port: General
Name: p1
Click the Next button
3. Wave Port: Terminals
1. Number of Terminals: 1,
2. For T1,
T1 click the Undefined column and select New Line
3. Using the coordinate entry fields, enter the vector position
X: 1.75,
1.75 Y: -0.9,
0.9 Z: -0.14,
0.14 Press the Enter key
4. Using the coordinate entry fields, enter the vertex
dX: 0.0,
0.0 dY: 0.0,
0.0 dZ: 0.08,
0.08 Press the Enter key
5. Click the Next button
4. Wave Port : Differential Pairs
1. Click the Next button
5. Wave Port : Post Processing
1. Full Port Impedance : 50
6. Click the Finish button
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7.1
Example – Bandpass Filter
Set Object Selection
Set select to objects
1. Select the menu item Edit > Select > Objects
Create rest of model by duplication
To select objects to be duplicated:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: feed1, feedpin1, feedprobe1, l1, l2, l3, l4
Note: Use the Ctrl + Left mouse button to select multiple objects
2. Click the OK button
To create rest of model:
1. Select the menu item Edit > Duplicate > Around Axis
Axis: Z
Angle: 180
Total Number: 2
Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
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7.1
Example – Bandpass Filter
Boundary Display
To verify the boundary setup:
1. Select the menu item HFSS > Boundary Display (Solver View)
2. From the Solver View of Boundaries, toggle the Visibility check box for the
boundaries you wish to display.
Note: The background (Perfect Conductor) is displayed as the outer
boundary.
Note: The Perfect Conductors are displayed as the smetal boundary.
Note: Select the menu item, View > Visibility to hide all of the
geometry objects. This makes it easier to see the boundary
3. Click the Close button when you are finished
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7.1
Example – Bandpass Filter
Analysis Setup
Creating an Analysis Setup
To create an analysis setup:
1. Select the menu item HFSS > Analysis Setup > Add Solution Setup
2. Solution Setup Window:
1. Click the General tab::
Solution Frequency:: 1.5GHz
Maximum Number of Passes: 15
Maximum Delta S per Pass: 0.02
2. Click the OK button
Adding a Frequency Sweep
To add a frequency sweep:
1. Select the menu item HFSS > Analysis Setup > Add Sweep
1. Select Solution Setup: Setup1
2. Click the OK button
2. Edit Sweep Window:
1. Sweep Type:: Fast
2. Frequency Setup Type:: Linear Count
Start: 0.6GHz
Stop:: 2.4GHz
Count:: 451
Save Fields: Checked
3. Click the OK button
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7.1
Example – Bandpass Filter
Save Project
To save the project:
1. In an Ansoft HFSS window, select the menu item File > Save As.
2. From the Save As window, type the Filename: hfss_bpf
3. Click the Save button
Analyze
Model Validation
To validate the model:
1. Select the menu item HFSS > Validation Check
2. Click the Close button
Note: To view any errors or warning messages, use the Message
Manager.
Analyze
To start the solution process:
1. Select the menu item HFSS > Analyze
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7.1
Example – Bandpass Filter
Solution Data
To view the Solution Data:
1. Select the menu item HFSS > Results > Solution Data
To view the Profile:
1. Click the Profile Tab.
To view the Convergence:
1. Click the Convergence Tab
Note: The default view is for convergence is Table.
Table Select
the Plot radio button to view a graphical representations of
the convergence data.
To view the Matrix Data:
1. Click the Matrix Data Tab
Note: To view a real-time update of the Matrix Data, set the
Simulation to Setup1, Last Adaptive
2. Click the Close button
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7.1
Example – Bandpass Filter
Create Reports
Create SS-parameter vs. Frequency
To Create a report:
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Terminal S Parameters
2. Display Type: Rectangular
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: Sweep1
2. Click the Y tab
1. Domain: Sweep
2. Category: Terminal SS-Parameters
3. Quantity: S(p1,p1), S(p2,p1)
4. Function: dB
5. Click the Add Trace button
3. Click the Done button
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7.1
Example – Bandpass Filter
Add a zoomed trace to the existing plot
To modify an existing plot:
Right mouse click on the existing plot
Select Modify Report… from the context menu
To add the trace:
1. Traces Window::
1. Solution: Setup1: Sweep1
2. Click the Y tab
1. Domain: Sweep
2. Category: Terminal SS-Parameters
3. Quantity: S(p2,p1)
4. Function: dB
5. Click the Add Trace button
3. From the listing at the top of the Traces window, select the axis
pulldown for the second instance of S(p2,p1), and select Y2
4. Click the Done button
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7.1
Example – Bandpass Filter
Change Plot Scale
Plot window:
1. Double click on the Y-axis on the right side of the plot,
2. Y Axis Properties Dialog
1. Click the Scaling tab
2. Autoscale: Unchecked
3. Min: -1.0
4. Max: 0.0
5. Click the OK button
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7.1
Example – Bandpass Filter
Field Overlays
Set Sources: Terminate Port
To set the port termination:
1. Select the menu item HFSS > Fields > Edit Sources
2. Edit Sources Window::
1. Select source:: p2:T1
Terminated:: Checked
Resistance:: 50
Reactance:: 0
2. Click the OK button
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7.1
Example – Bandpass Filter
Field Overlays (Continued)
Create Field Overlay
Select the Global XY Plane
1. Using the Model Tree, expand Planes
1. Select Global:XY
2. Select the menu item HFSS > Fields > Fields > E > Mag_E
3. Create Field Plot Window
1. Solution: Setup1 : LastAdaptive
2. Quantity: Mag_E
3. In Volume: All
4. Click the Done button
To modify the attributes of a field plot:
1. Select the menu item HFSS > Fields > Modify Plot Attributes
2. Select Plot Folder Window:
1. Select: E Field
2. Click the OK button
3. E-Field1 Window:
1. Click the Scale tab
1. Select Use Limits
2. Min: 5
3. Max: 1500
4. Scale: Log
2. Click the Close button
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7.2
Example – Microstrip Bandstop Filter
The Microstrip Bandstop Filter
This example is intended to show you how to create, simulate, and analyze a
microstrip filter using the Ansoft HFSS Design Environment.
L1
S
L2
Nominal Design:
L1 = 91.2 mil
L2 = 86.4 mil
S = 4.8 mil
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7.2
Example – Microstrip Bandstop Filter
Getting Started
Launching Ansoft HFSS
1.
To access Ansoft HFSS, click the Microsoft Start button, select Programs,
Programs and
select the Ansoft > HFSS 10 program group. Click HFSS 10.
10
Setting Tool Options
To set the tool options:
Note: In order to follow the steps outlined in this example, verify that the
following tool options are set :
1. Select the menu item Tools > Options > HFSS Options
2. HFSS Options Window:
1. Click the General tab
Use Wizards for data entry when creating new boundaries:: Checked
Duplicate boundaries with geometry:: Checked
2. Click the OK button
3. Select the menu item Tools > Options > 3D Modeler Options.
Options
4. 3D Modeler Options Window:
1. Click the Operation tab
Automatically cover closed polylines:: Checked
2. Click the Drawing tab
Edit property of new primitives:: Checked
3. Click the OK button
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7.2
Example – Microstrip Bandstop Filter
Opening a New Project
To open a new project:
In an Ansoft HFSS window, click the On the Standard toolbar, or select
the menu item File > New.
From the Project menu, select Insert HFSS Design.
Set Solution Type
To set the solution type:
Select the menu item HFSS > Solution Type
Solution Type Window:
Choose Driven Terminal
Click the OK button
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7.2
Example – Microstrip Bandstop Filter
Creating the 3D Model
Set Model Units
To set the units:
1. Select the menu item 3D Modeler > Units
2. Set Model Units:
1. Select Units: mil
2. Click the OK button
Set Default Material
To set the default material:
1. Using the 3D Modeler Materials toolbar, choose Select
2. Select Definition Window:
1. Type pec in the Search by Name field
2. Click the OK button
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7.2
Example – Microstrip Bandstop Filter
Create Input 1
To create the input:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the box:
dX: -4.8,
4.8 dY: -14.4,
14.4 dZ: 0.1,
0.1 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Input1
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Create L1
To create L1:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the box:
dX: -4.8,
4.8 dY: 91.2,
91.2 dZ: 0.1,
0.1 Press the Enter key
To parameterize the object:
1. Select the Command tab from the Properties window
2. For YSize,
YSize type: L1, Click the Tab key to accept
1. Add Variable L1:
L1 91.2mil,
91.2mil Click the OK button
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: L1
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
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7.2
Example – Microstrip Bandstop Filter
Create S for Stub 1
To create S:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the box:
dX: 4.8,
4.8 dY: 4.8,
4.8 dZ: 0.1,
0.1 Press the Enter key
To parameterize the object:
1. Select the Command tab from the Properties window
2. For XSize,
XSize type: S, Click the Tab key to accept
1. Add Variable S: 4.8mil,
4.8mil Click the OK button
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: S_Stub1
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
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7.2
Example – Microstrip Bandstop Filter
Set Grid Plane
To set the grid plane:
1. Select the menu item 3D Modeler > Grid Plane > XZ
Create Source 1
To create source:
1. Select the menu item Draw > Rectangle
2. Using the coordinate entry fields, enter the box position
X: 0.0,
14.4,
0.0 Y: -14.4
14.4 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the base
rectangle:
dX: -4.8,
4.8 dY: 0.0,
0.0 dZ: -5.0,
5.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Source1
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
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7.2
Example – Microstrip Bandstop Filter
Assign Excitation
To select the object Source:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Source1
2. Click the OK button
Note:
Note You can also select the object from the Model Tree
To assign lumped port excitation
1. Select the menu item HFSS > Excitations > Assign > Lumped Port
2. Lumped Port : General
1. Name: p1,
p1
2. Resistance: 50
3. Reactance: 0
4. Click the Next button
3. Lumped Port : Terminals
1. Number of Terminals: 1,
2. For T1,
T1 click the Undefined column and select New Line
3. Using the coordinate entry fields, enter the vector position
X: -2.4,
2.4 Y: -14.4,
14.4 Z: -5.0,
5.0 Press the Enter key
4. Using the coordinate entry fields, enter the vertex
dX: 0.0,
0.0 dY: 0.0,
0.0 dZ: 5.0,
5.0 Press the Enter key
4. Click the Next button
5. Wave Port : Post Processing
1. Full Port Impedance : 50
Set Grid Plane
To set the grid plane:
1. Select the menu item 3D Modeler > Grid Plane > XY
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7.2
Example – Microstrip Bandstop Filter
Create Offset Coordinate System
To create an offset Coordinate System:
1. Select the menu item 3D Modeler > Coordinate System > Create >
Relative CS > Offset
2.
Using the coordinate entry fields, enter the origin
X: 4.8,
4.8 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
Set Working Coordinate System
To set the working coordinate system:
1. Select the menu item 3D Modeler > Coordinate System > Set Working CS
2. Select Coordinate System Window,
1. From the list, select the CS: RelativeCS1
2. Click the Select button
To set the name:
Note: After selecting the coordinate system, its properties will be displayed
in the property window. If you do not see the properties, repeat the steps to
set the working coordinate system, or select the CS from the model tree.
1. For the Value of Name type: CS_Stub1
To parameterize the origin:
Note: After selecting the coordinate system, its properties will be displayed
in the property window. If you do not see the properties, repeat the steps to
set the working coordinate system, or select the CS from the model tree
1. For the Value of Origin type: S, 0, 0, Click the Tab key to accept
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7.2
Example – Microstrip Bandstop Filter
Create L2 for Stub 1
To create L2:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the box:
dX: 4.8,
4.8 dY: 86.4,
86.4 dZ: 0.1,
0.1 Press the Enter key
To parameterize the object:
1. Select the Command tab from the Properties window
2. For YSize,
YSize type: L2, Click the Tab key to accept
1. Add Variable L2:
L2 86.4mil,
86.4mil Click the OK button
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: L2_Stub1
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Set Working Coordinate System
To set the working coordinate system:
1. Select the menu item 3D Modeler > Coordinate System > Set Working CS
2. Select Coordinate System Window,
1. From the list, select the CS: Global
2. Click the Select button
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7.2
Example – Microstrip Bandstop Filter
Create Offset Coordinate System
To create an offset Coordinate System:
1. Select the menu item 3D Modeler > Coordinate System > Create >
Relative CS > Offset
2.
Using the coordinate entry fields, enter the origin
X: -4.8
4.8,
4.8 Y: 91.2,
91.2 Z: 0.0,
0.0 Press the Enter key
Set Working Coordinate System
To set the working coordinate system:
1. Select the menu item 3D Modeler > Coordinate System > Set Working CS
2. Select Coordinate System Window,
1. From the list, select the CS: RelativeCS1
2. Click the Select button
To set the name:
Note: After selecting the coordinate system, its properties will be displayed
in the property window. If you do not see the properties, repeat the steps to
set the working coordinate system, or select the CS from the model tree.
1. For the Value of Name type: CS_L1
To parameterize the origin:
Note: After selecting the coordinate system, its properties will be displayed
in the property window. If you do not see the properties, repeat the steps to
set the working coordinate system, or select the CS from the model tree
1. For the Value of Origin type: -4.8, L1, 0, Click the Tab key to accept
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7.2
Example – Microstrip Bandstop Filter
Create Input2
To create the input:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the box:
dX: 4.8,
4.8 dY: 4.8+14.4,
4.8+14.4 dZ: 0.1,
0.1 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Input2
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Create S for Stub 2
To create S:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the box:
dX: -4.8,
4.8 dY: 4.8,
4.8 dZ: 0.1,
0.1 Press the Enter key
To parameterize the object:
1. Select the Command tab from the Properties window
2. For XSize,
S, Click the Tab key to accept
XSize type: -S,
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: S_Stub2
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
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7.2
Example – Microstrip Bandstop Filter
Set Grid Plane
To set the grid plane:
1. Select the menu item 3D Modeler > Grid Plane > XZ
Create Source 2
To create source:
1. Select the menu item Draw > Rectangle
2. Using the coordinate entry fields, enter the box position
X: 0.0,
0.0 Y: 4.8+14.4,
4.8+14.4 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the base
rectangle:
dX: 4.8,
4.8 dY: 0.0,
0.0 dZ: -5.0,
5.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Source2
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
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7.2
Example – Microstrip Bandstop Filter
Assign Excitation
To select the object Source:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Source2
2. Click the OK button
Note:
Note You can also select the object from the Model Tree
To assign lumped port excitation
1. Select the menu item HFSS > Excitations > Assign > Lumped Port
2. Lumped Port : General
1. Name: p2,
p2
2. Resistance: 50
3. Reactance: 0
4. Click the Next button
3. Lumped Port : Terminals
1. Number of Terminals: 1,
2. For T1,
T1 click the Undefined column and select New Line
3. Using the coordinate entry fields, enter the vector position
X: 2.4,
2.4 Y: 19.2,
19.2 Z: -5.0,
5.0 Press the Enter key
4. Using the coordinate entry fields, enter the vertex
dX: 0.0,
0.0 dY: 0.0,
0.0 dZ: 5.0,
5.0 Press the Enter key
4. Click the Next button
5. Wave Port : Post Processing
1. Full Port Impedance : 50
Set Grid Plane
To set the grid plane:
1. Select the menu item 3D Modeler > Grid Plane > XY
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7.2
Example – Microstrip Bandstop Filter
Create Offset Coordinate System
To create an offset Coordinate System:
1. Select the menu item 3D Modeler > Coordinate System > Create >
Relative CS > Offset
2.
Using the coordinate entry fields, enter the origin
X: -4.8
4.8,
4.8 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
Set Working Coordinate System
To set the working coordinate system:
1. Select the menu item 3D Modeler > Coordinate System > Set Working CS
2. Select Coordinate System Window,
1. From the list, select the CS: RelativeCS1
2. Click the Select button
To set the name:
Note: After selecting the coordinate system, its properties will be displayed
in the property window. If you do not see the properties, repeat the steps to
set the working coordinate system, or select the CS from the model tree.
1. For the Value of Name type: CS_Stub2
To parameterize the origin:
Note: After selecting the coordinate system, its properties will be displayed
in the property window. If you do not see the properties, repeat the steps to
set the working coordinate system, or select the CS from the model tree
1. For the Value of Origin type: -S, 0, 0, Click the Tab key to accept
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7.2
Example – Microstrip Bandstop Filter
Create L2 for Stub 2
To create L2:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: 0.0,
0.0 Y: 4.8,
4.8 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the box:
dX: -4.8,
4.8 dY: -86.4,
86.4 dZ: 0.1,
0.1 Press the Enter key
To parameterize the object:
1. Select the Command tab from the Properties window
2. For YSize,
YSize type: -L2, Click the Tab key to accept
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: L2_Stub2
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
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7.2
Example – Microstrip Bandstop Filter
Set Working Coordinate System
To set the working coordinate system:
1. Select the menu item 3D Modeler > Coordinate System > Set Working CS
2. Select Coordinate System Window,
1. From the list, select the CS: Global
2. Click the Select button
Create Ground
To create the ground:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: -34.4,
34.4 Y: -34.4,
34.4 Z: -5.0,
5.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the box:
dX: 64.0,
64.0 dY: 164.8,
164.8 dZ: -0.1,
0.1 Press the Enter key
To parameterize the object:
1. Select the Command tab from the Properties window
2. For Position,
Position type: -S-29.6mil, -34.4mil, -5mil, Click the Tab key to accept
3. For XSize,
XSize type: 54.4mil+2*S, Click the Tab key to accept
4. For YSize,
YSize type: 73.6mil+L1, Click the Tab key to accept
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Ground
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
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7.2
Example – Microstrip Bandstop Filter
Add New Material
To add a new material:
1. Using the 3D Modeler Materials toolbar, choose Select
2. From the Select Definition window, click the Add Material button
3. View/Edit Material Window:
1. Material Name: My_Alumina
2. Relative Permittivity: 9.9
3. Click the OK button
4. Click the OK button
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7.2
Example – Microstrip Bandstop Filter
Create Substrate
To create the substrate:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: -34.4,
34.4 Y: -34.4,
34.4 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the box:
dX: 64.0,
64.0 dY: 164.8,
164.8 dZ: -5.0,
5.0 Press the Enter key
To parameterize the object:
1. Select the Command tab from the Properties window
2. For Position,
Position type: -S-29.6mil, -34.4mil, 0mil, Click the Tab key to accept
3. For XSize,
XSize type: 54.4mil+2*S, Click the Tab key to accept
4. For YSize,
YSize type: 73.6mil+L1, Click the Tab key to accept
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Substrate
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Set Default Material
To set the default material:
1. Using the 3D Modeler Materials toolbar, choose vacuum
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7.2
Example – Microstrip Bandstop Filter
Create Air
To create the Air:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: -34.4,
34.4 Y: -34.4,
34.4 Z: -5.1,
5.1 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the box:
dX: 64.0,
64.0 dY: 164.8,
164.8 dZ: 50.0,
50.0 Press the Enter key
To parameterize the object:
1. Select the Command tab from the Properties window
2. For Position,
Position type: -S-29.6mil, -34.4mil, -5.1mil, Click the Tab key to accept
3. For XSize,
XSize type: 54.4mil+2*S, Click the Tab key to accept
4. For YSize,
YSize type: 73.6mil+L1, Click the Tab key to accept
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Air
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Create Radiation Boundary
To select the object Air:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Air
2. Click the OK button
To create a radiation boundary
1. Select the menu item HFSS > Boundaries > Assign > Radiation
2. Radiation Boundary Window
Name: Rad1
Click the OK button
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7.2
Example – Microstrip Bandstop Filter
Boundary Display
To verify the boundary setup:
1. Select the menu item HFSS > Boundary Display (Solver View)
2. From the Solver View of Boundaries, toggle the Visibility check box for the
boundaries you wish to display.
Note: The background (Perfect Conductor) is displayed as the outer
boundary.
Note: The Perfect Conductors are displayed as the smetal boundary.
Note: Select the menu item, View > Visibility to hide all of the
geometry objects. This makes it easier to see the boundary
3. Click the Close button when you are finished
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7.2
Example – Microstrip Bandstop Filter
Analysis Setup
Creating an Analysis Setup
To create an analysis setup:
1. Select the menu item HFSS > Analysis Setup > Add Solution Setup
2. Solution Setup Window:
1. Click the General tab::
Solution Frequency:: 20.0GHz
Maximum Number of Passes: 20
Maximum Delta S per Pass: 0.02
2. Click the OK button
Adding a Frequency Sweep
To add a frequency sweep:
1. Select the menu item HFSS > Analysis Setup > Add Sweep
1. Select Solution Setup: Setup1
2. Click the OK button
2. Edit Sweep Window:
1. Sweep Type:: Fast
2. Frequency Setup Type:: Linear Step
Start: 4.0GHz
Stop:: 20.0GHz
Step:: 0.05GHz
Save Fields: Checked
3. Click the OK button
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7.2
Example – Microstrip Bandstop Filter
Save Project
To save the project:
1. In an Ansoft HFSS window, select the menu item File > Save As.
2. From the Save As window, type the Filename: hfss_msbsf
3. Click the Save button
Analyze
Model Validation
To validate the model:
1. Select the menu item HFSS > Validation Check
2. Click the Close button
Note: To view any errors or warning messages, use the Message
Manager.
Analyze
To start the solution process:
1. Select the menu item HFSS > Analyze
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7.2
Example – Microstrip Bandstop Filter
Solution Data
To view the Solution Data:
1. Select the menu item HFSS > Results > Solution Data
To view the Profile:
1. Click the Profile Tab.
To view the Convergence:
1. Click the Convergence Tab
Note: The default view is for convergence is Table.
Table Select
the Plot radio button to view a graphical representations of
the convergence data.
To view the Matrix Data:
1. Click the Matrix Data Tab
Note: To view a real-time update of the Matrix Data, set the
Simulation to Setup1, Last Adaptive
2. Click the Close button
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7.2
Example – Microstrip Bandstop Filter
Create Reports
Create SS-parameter vs. Frequency
To Create a report:
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Terminal S Parameters
2. Display Type: Rectangular
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: Sweep1
2. Click the Y tab
1. Domain: Sweep
2. Category: Terminal SS-Parameters
3. Quantity: St(p1,p1), St(p2,p1)
4. Function: dB
5. Click the Add Trace button
3. Click the Done button
Ansoft High Frequency Structure Simulator v10 User’s Guide
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Chapter 8.0
Chapter 8.0 – Signal Integrity Examples
8.1 – LVDS Differential Pair
Includes Optimetrics Example
8.1a – LVDS Differential Pair Transient Simulation (Ansoft Designer)
8.2 – Segmented Return Path
8.2a – Segmented Return Path TDR (Ansoft Designer)
8.3 – Non-Ideal Planes
8.4 – Return Path
Ansoft High Frequency Structure Simulator v10 User’s Guide
8.1a
Example – LVDS Differential Pair
LVDS Differential Pair
This differential pair example is intended to show you how to create, simulate,
and analyze a differential pair using the Ansoft HFSS Design Environment.
Low Voltage Differential Signaling (LVDS) technology is used for highperformance backplanes. The LVDS is used for multi-point communications and
uses a bus similar to system show below. The following illustrations detail the
passive device you will be creating.
Nominal Design:
Traces:
LAYER 1 (TOP SIDE)
Width= 6mil
LAYER 2 (SIGNAL 1)
26mil
Spacing= 18mil
Thickness=0.7mil
LAYER 3 (BOTTOM SIDE)
Length: 1000mil
Substrate:
Thickness=26mil
εr= 4.4
Ansoft High Frequency Structure Simulator v10 User’s Guide
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8.1a
Example – LVDS Differential Pair
Ansoft HFSS Design Environment
The following features of the Ansoft HFSS Design Environment are used to
create this passive device model.
3D Solid Modeling
Primitives: Box, Rectangles
Boolean Operations: Duplicate Along Line, Sweep Along Vector
Boundaries/Excitations
Ports: Wave Ports, Terminal Lines
Analysis
Sweep: Interpolating
Results
Cartesian and Smith Chart plotting
Field Overlays
3D Field Plots
Ansoft High Frequency Structure Simulator v10 User’s Guide
8.1a-2
8.1a
Example – LVDS Differential Pair
Design Review
Before we jump into setting up this device lets review the design.
Trace Width = 6mils
Trace Length= 1000mils
Dielectric Height= 13mils x 2
1/2oz copper Traces/Grounds= 0.7mils
Port Size= ???
Port Width
From the Using Ports section, the port width should be at least 3-5 times
the stackup(78-130mils). Since the traces are not centered, lets use 5x
and add the pair spacing(18mils) for a total port/model width of 220mils.
Trace Length
Since we are modeling a uniform transmission line, we do not need to
simulate the 1000mils length. Lets reduce the model to 100 mils and use
de-embedding to add the extra length.
Material Properties
To start with, lets make an engineering assumption that the material
properties are constant over frequency. In addition, we will assume that
the modeling the traces as perfect conductors will not have an impact on
the performance of the device. This will speed up the simulation. As an
additional exercise, the model can be modified to include frequency
dependent materials and lossy conductors.
Ground Planes
Since we are ignoring the metal conductivity, we do not need to create
objects for the ground planes. Instead, we will utilize the background
(Perfect Conductor) boundary. If we need to investigate the effects of
copper, a finite conductivity boundary condition can be used to simulate the
copper ground planes.
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8.1a
Example – LVDS Differential Pair
Solution Setup
Since we are going to use the model for SPICE simulation, the frequency range
of interest is going to be determined by the rise-time(tr) of the input signal. The
maximum frequency is calculated by taking 0.5/tr, or the knee frequency, and
multiplying it by the number of samples per tr. The minimum frequency should
be selected as close to DC as possible.
The following values will be used for the Solution Setup
Rise-Time(tr): 330ps
Number of Samples: 5
Upper Frequency: (0.5/330ps)*5 ~ 7.58GHz or 8.0GHz
Lower Frequency: 0.01GHz
Frequency Spacing: 0.01GHz
Single(Adaptive) Frequency: 8.0GHz
Adaptive Passes: 10
Delta S: 0.02
Sweep Type: Interpolating
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8.1a-4
8.1a
Example – LVDS Differential Pair
Getting Started
Launching Ansoft HFSS
1.
To access Ansoft HFSS, click the Microsoft Start button, select Programs,
Programs and select
the Ansoft, HFSS 10 program group. Click HFSS 10.
10
Setting Tool Options
To set the tool options:
Note: In order to follow the steps outlined in this example, verify that the
following tool options are set :
1. Select the menu item Tools > Options > HFSS Options
2. HFSS Options Window:
1. Click the General tab
Use Wizards for data entry when creating new boundaries:: Checked
Duplicate boundaries with geometry:: Checked
2. Click the OK button
3. Select the menu item Tools > Options > 3D Modeler Options.
Options
4. 3D Modeler Options Window:
1. Click the Operation tab
Automatically cover closed polylines:: Checked
2. Click the Drawing tab
Edit property of new primitives:: Checked
3. Click the OK button
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8.1a
Example – LVDS Differential Pair
Opening a New Project
To open a new project:
1. In an Ansoft HFSS window, click the On the Standard toolbar, or select
the menu item File > New.
2. From the Project menu, select Insert HFSS Design.
Set Solution Type
To set the solution type:
1. Select the menu item HFSS > Solution Type
2. Solution Type Window:
1. Choose Driven Terminal
2. Click the OK button
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8.1a-6
8.1a
Example – LVDS Differential Pair
Creating the 3D Model
Set Model Units
To set the units:
1. Select the menu item 3D Modeler > Units
2. Set Model Units:
1. Select Units: mil
2. Click the OK button
Set Default Material
To set the default material:
1. Using the 3D Modeler Materials toolbar, choose Select
2. Select Definition Window:
1. Type pec in the Search by Name field
2. Click the OK button
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8.1a
Example – LVDS Differential Pair
Create Trace 1
To create trace 1:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: 0.0,
0.0 Y: 9.0,
9.0 Z: -0.35,
0.35 Press the Enter key
3.
Using the coordinate entry fields, enter the opposite corner of the base
rectangle:
dX: 100.0,
100.0 dY: 6.0,
6.0 dZ: 0.7, Press the Enter key
To parameterize the object:
1. Select the Command tab from the Properties window
2. For Position,
Position type: 0.0mil, S/2, -0.35mil,
0.35mil Click the Tab key to accept
Add Variable S: 18mil,
18mil Click the OK button
3. For YSize,
YSize type: W, Click the Tab key to accept
Add Variable W: 6mil,
6mil Click the OK button
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: trace1
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Or press the CTRL+D key
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8.1a
Example – LVDS Differential Pair
Create Trace 2
To create trace 2:
1. Select the menu item Edit > Select All Visible. Or press the CTRL+A key.
2. Select the menu item, Edit > Duplicate > Mirror.
1. Input the anchor point of the mirror plane:
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
2. Input the target point of the vector normal to the mirror plane:
dX: 0.0,
0.0 dY: -1.0,
1.0 dZ: 0.0,
0.0 Press the Enter key
To set the name:
1. Select the menu item HFSS > List
2. From the Model tab, select the object named trace1_1
3. Click the Properties button
1. For the Value of Name type: trace2
2. Click the OK button
4. Click the Done button
To fit the view:
1. Select the menu item View > Fit All > Active View.
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8.1a-9
8.1a
Example – LVDS Differential Pair
Add New Material
To add a new material:
1. Using the 3D Modeler Materials toolbar, choose Select
2. From the Select Definition window, click the Add Material button
3. View/Edit Material Window:
1. Material Name: My_FR4
2. Relative Permittivity: 4.4
3. Click the OK button
4. Click the OK button
Ansoft High Frequency Structure Simulator v10 User’s Guide
8.1a-10
8.1a
Example – LVDS Differential Pair
Create Substrate
To create substrate:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: 0.0,
0.0 Y: -100.0,
100.0 Z: -13.0, Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the base
rectangle:
dX: 100.0,
100.0 dY: 200.0,
200.0 dZ: 26.0, Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: substrate
To set the transparency:
1. Select the Attribute tab from the Properties window.
2. Click the button for Transparency
1. Move the slide bar to 0.8 (Opaque=0, Transparency=1)
2. Click the OK button
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
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8.1a-11
8.1a
Example – LVDS Differential Pair
Create Wave Port Excitation 1
Note: This structure requires 2 ports with 2 terminal lines per port. We could use
face selection to select the ends of the substrate that represent the port, define
terminal lines, assign excitation, and repeat for port2. But since we can duplicate
port definitions, it is more efficient to define a rectangle with the appropriate port
definition and copy it to the location of the 2nd port. The second method is
described here:
To set grid plane
Select the menu item 3D Modeler > Grid Plane > YZ
To create a rectangle that represents the port:
1. Select the menu item Draw > Rectangle
2. Using the coordinate entry fields, enter the rectangle position
X: 0.0,
0.0 Y: -100.0,
100.0 Z: -13.0,
13.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the rectangle:
dX: 0.0,
0.0 dY: 200.0,
200.0 dZ: 26.0,
26.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Port1
3. Click the OK button
To select the object Port1:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Port1
2. Click the OK button
Note:
Note You can also select the object from the
Model Tree
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8.1a-12
8.1a
Example – LVDS Differential Pair
Create Wave Port Excitation 1 (Continued)
To assign wave port excitation
1. Select the menu item HFSS > Excitations > Assign > Wave Port
2. Wave Port : General
1. Name: p1
2. Click the Next button
3. Wave Port : Terminals
1. Number of Terminals: 2, Click the Update button
2. For T1,
T1 click the Undefined column and select New Line
3. Using the coordinate entry fields, enter the vector position
X: 0.0,
0.0 Y: 0.0,
0.0 Z: -13.0,
13.0 Press the Enter key
4. Using the coordinate entry fields, enter the vertex
dX: 0.0,
0.0 dY: 12.0,
12.0 dZ: 12.65,
12.65 Press the Enter key
5. For T2,
T2 click the Undefined column and select New Line
6. Using the coordinate entry fields, enter the vector position
X: 0.0,
0.0 Y: 0.0,
0.0 Z: -13.0,
13.0 Press the Enter key
7. Using the coordinate entry fields, enter the vertex
dX: 0.0,
0.0 dY: -12.0,
12.0 dZ: 12.65,
12.65 Press the Enter key
8. Click the Next button
4. Wave Port : Differential Pairs
1. Click the New Pair button
2. Click the Next button
5. Wave Port : Post Processing
6. Click the Finish button
Wave Port Face
Terminal Lines
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8.1a-13
8.1a
Example – LVDS Differential Pair
Create Wave Port Excitation 2
To select the object Port1:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Port1
2. Click the OK button
To duplicate the port:
1. Select the menu item, Edit > Duplicate > Along Line
2. Using the coordinate entry fields, enter the first point of the duplicate vector
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the second point of the duplicate
vector
dX: 100.0,
100.0 dY: 0.0,
0.0 dZ: 0.0, Press the Enter key
4. Duplicate Along Line Windows
1. Total Number: 2
2. Click the OK button
To set deembedding:
deembedding:
1. Select the menu item HFSS > List
2. From the Excitations tab, select the excitation named p2
3. Click the Properties button
1. Deembed: Checked
2. Deembed Distance: -900mil (Positive Values are into the Port)
3. Click the OK button
4. Click the Done button
Ansoft High Frequency Structure Simulator v10 User’s Guide
8.1a-14
8.1a
Example – LVDS Differential Pair
Boundary Display
To verify the boundary setup:
1. Select the menu item HFSS > Boundary Display (Solver View)
2. From the Solver View of Boundaries, toggle the Visibility check box for the
boundaries you wish to display.
Note: The background (Perfect Conductor) is displayed as the outer
boundary.
Note: The Perfect Conductors are displayed as the smetal boundary.
Note: Select the menu item, View > Visibility to hide all of the
geometry objects. This makes it easier to see the boundary
3. Click the Close button when you are finished.
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8.1a-15
8.1a
Example – LVDS Differential Pair
Analysis Setup
Creating an Analysis Setup
To create an analysis setup:
1. Select the menu item HFSS > Analysis Setup > Add Solution Setup
2. Solution Setup Window:
1. Click the General tab::
Solution Frequency:: 8.0GHz
Maximum Number of Passes: 20
Maximum Delta S: 0.02
2. Click the Options tab::
Do Lambda Refinement: Checked
Target:: 0.05
Use Low-Order Solution Basis: Checked
3. Click the OK button
Adding a Frequency Sweep
To add a frequency sweep:
1. Select the menu item HFSS > Analysis Setup > Add Sweep
1. Select Solution Setup: Setup1
2. Click the OK button
2. Edit Sweep Window:
1. Sweep Type:: Interpolating
2. Click the Setup Interpolation Basis button
Max Solutions:: 20
Error Tolerance:: 0.5%
User All Entries: Selected
Click OK
3. Extrapolate to DC:: Checked
Minimum Solve Frequency:: 0.01 GHz
4. Snap Magnitude to 0 or 1 at DC: Unchecked
5. Frequency Setup Type:: Linear Step
Stop:: 8.0GHz
Step:: 0.01GHz
6. Click the OK button
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8.1a-16
8.1a
Example – LVDS Differential Pair
Save Project
To save the project:
1. In an Ansoft HFSS window, select the menu item File > Save As.
2. From the Save As window, type the Filename: hfss_lvds_diffpair
3. Click the Save button
Analyze
Model Validation
To validate the model:
1. Select the menu item HFSS > Validation Check
2. Click the Close button
Note: To view any errors or warning messages, see the Message
Manager.
Analyze
To start the solution process:
1. Select the menu item HFSS > Analyze
Ansoft High Frequency Structure Simulator v10 User’s Guide
8.1a-17
8.1a
Example – LVDS Differential Pair
Solution Data
To view the Solution Data:
1. Select the menu item HFSS > Results > Solution Data
To view the Profile:
1. Click the Profile Tab.
To view the Convergence:
1. Click the Convergence Tab
Note: The default view is for convergence is Table.
Table Select
the Plot radio button to view a graphical representations of
the convergence data.
To view the Matrix Data:
1. Click the Matrix Data Tab
Note: To view a real-time update of the Matrix Data, set the
Simulation to Setup1, Last Adaptive
2. Click the Close button
Ansoft High Frequency Structure Simulator v10 User’s Guide
8.1a-18
8.1a
Example – LVDS Differential Pair
Create Reports
Create Differential Pair SS-Parameter Plot
To create a report:
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Terminal S Parameters
2. Display Type: Rectangular
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: Sweep1
2. Domain: Sweep
3. Click the Y tab
1. Category: Terminal S Parameters
2. Quantity: St(p1:Diff1,p1:Diff1), St(p1:Diff1,p1:Comm1),
St(p1:Diff1,p2:Diff1)
3. Function: dB
4. Click the Add Trace button
4. Click the Done button
Ansoft High Frequency Structure Simulator v10 User’s Guide
8.1a-19
8.1a
Example – LVDS Differential Pair
Create Differential and Common Pair Impedances Data Table
To create a report:
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Terminal S Parameters
2. Display Type: Data Table
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: LastAdaptive
2. Click the Y tab
1. Category: Terminal Port Zo
2. Quantity: Zot(p1:Diff1,p1:Diff1), Zot(p1:Comm1,p1:Comm1)
3. Function: mag
4. Click the Add Trace button
3. Click the Done button
Ansoft High Frequency Structure Simulator v10 User’s Guide
8.1a-20
8.1a
Example – LVDS Differential Pair
Matrix Data - Export SS-parameters to a file
To view the Matrix Data:
1. Select the menu item HFSS > Results > Solution Data,
2. Solution Data dialog
1. Click the Matrix Data Tab
2. Simulation: Setup1, Sweep1
3. Click the Export button.
1. Filename: hfss_lvds_diffpair
2. Save as Type: Touchstone
3. Click the Save button
4. Click the OK button to accept 50 ohm reference impedance
4. Click the Close button
Ansoft High Frequency Structure Simulator v10 User’s Guide
8.1a-21
8.1a
Example – LVDS Differential Pair
Field Overlays
Set Sources: Common
To set the field excitation:
1. Select the menu item HFSS > Fields > Edit Sources
2. Edit Sources Window::
1. Select source:: p1:T1
Magnitude:: 1
Phase:: 0
2. Select source:: p1:T2
Magnitude:: 1
Phase:: 0
3. Select source:: p2:T1
Terminated:: Checked
Resistance:: 50
Reactance:: 0
4. Select source:: p2:T2
Terminated:: Checked
Resistance:: 50
Reactance:: 0
5. Click the OK button
Ansoft High Frequency Structure Simulator v10 User’s Guide
8.1a-22
8.1a
Example – LVDS Differential Pair
Create Field Overlay
To create a field plot:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Port1
2. Click the OK button
3. Select the menu item HFSS > Fields > Fields > E > Mag_E
4. Create Field Plot Window
1. Solution: Setup1 : LastAdaptive
2. Quantity: Mag_E
3. In Volume: All
4. Click the Done button
To modify the attributes of a field plot:
1. Select the menu item HFSS > Fields > Modify Plot Attributes
2. Select Plot Folder Window:
1. Select: E Field
2. Click the OK button
3. E-Field Window:
1. Click the Scale tab
1. Select Use Limits
2. Min: 5
3. Max: 10000
4. Scale: Log
2. Click the Plot tab
1. IsoValType: Fringe
2. If real time mode is not checked, click the Apply button.
4. Click the Close button
Ansoft High Frequency Structure Simulator v10 User’s Guide
8.1a-23
8.1a
Example – LVDS Differential Pair
Create Field Overlay
To create a field plot:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Port1
2. Click the OK button
3. Select the menu item HFSS > Fields > Fields > E > Vector_E
4. Create Field Plot Window
1. Solution: Setup1 : LastAdaptive
2. Quantity: Vector_E
3. In Volume: All
4. Click the Done button
To modify the attributes of a field plot:
1. Select the menu item HFSS > Fields > Modify Plot Attributes
2. Select Plot Folder Window:
1. Select: E Field
2. Click the OK button
3. E-Field Window:
1. Click the Marker/Arrow tab
1. Type: Cylinder
2. Map Size: Unchecked
3. Arrow Tale: Unchecked
4. If real time mode is not checked, click the Apply button.
4. Click the Close button
Ansoft High Frequency Structure Simulator v10 User’s Guide
8.1a-24
8.1a
Example – LVDS Differential Pair
Set Differential Mode Field Excitation
To set the field excitation:
1. Select the menu item HFSS > Fields > Edit Sources
2. Edit Sources Window::
1. Select source:: p1:T1
Magnitude:: 1
Phase:: 0
2. Select source:: p1:T2
Magnitude:: 1
Phase:: 180
3. Select source:: p2:T1
Terminated:: Checked
Resistance:: 50
Reactance:: 0
4. Select source:: p2:T2
Terminated:: Checked
Resistance:: 50
Reactance:: 0
5. Click the OK button
The field plots will automatically be updated to reflect the changes.
Ansoft High Frequency Structure Simulator v10 User’s Guide
8.1a-25
8.1a
Example – LVDS Differential Pair
Optimetrics Setup – Parametric Sweep
During the design of a device, it is common practice to develop design trends based on
swept parameters. Ansoft HFSS with Optimetrics Parametric Sweep can automatically
create these design curves.
We will parameterize this design using two variables:
1.
2.
Variable W will vary the width of traces: 6 ≤ W ≤ 12 mils
Variable S will vary the spacing between traces: 15 ≤ S ≤ 21 mils
6 ≤ W ≤ 12 mils
15 ≤ S ≤ 21 mils
W
S
In the post processor you will able to display results and see how Differential impedance
changes with the respect to trace width and spacing between traces.
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8.1a-26
8.1a
Example – LVDS Differential Pair
Optimetrics Setup – Parametric Sweep
Add a Parametric Sweep
1.
2.
Select the menu item HFSS > Optimetrics Analysis > Add Parametric
Setup Sweep Analysis Window:
1. Click the Sweep Definitions tab::
1. Click the Add button
2. Add/Edit Sweep Dialog
1. Variable: W
2. Select Linear Count
3. Start: 6mil
4. Stop: 12mil
5. Count: 3
6. Click the Add >> button
7. Variable: S
8. Select Linear Count
9. Start: 15mil
10. Stop: 21mil
11. Count: 3
12. Click the Add >> button
13. Click the OK button
2. Click on the Options tab::
1. Save Fields And Mesh:: Checked
3. Click the OK button
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8.1a-27
8.1a
Example – LVDS Differential Pair
Save Project
To save the project:
1. In an Ansoft HFSS window, select the menu item File > Save.
Analyze
Model Validation
To validate the model:
1. Select the menu item HFSS > Validation Check
2. Click the Close button
Note: To view any errors or warning messages, use the Message
Manager.
Analyze
To start the solution process:
1. Expand the Project Tree to display the items listed under Optimetrics
2. Right-click the mouse on ParametricSetup1 and choose Analyze
Ansoft High Frequency Structure Simulator v10 User’s Guide
8.1a-28
8.1a
Example – LVDS Differential Pair
Create Reports
Create Terminal Port Zo vs S
To Create a report:
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Terminal S Parameters
2. Display Type: Rectangular
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: LastAdaptive
2. Click the Sweeps tab
1. Select the Sweep Design and Project Variable Values button
2. From the table, select Freq from the Name column and toggle
the Primary Sweep to S
3. Click the Y tab
1. Category: Terminal Port Zo
2. Quantity: Zot(p1:Diff1,p1:Diff1), Zot(p1:Comm1,p1:Comm1)
3. Function: mag
4. Click the Add Trace button
4. Click the Done button
Ansoft High Frequency Structure Simulator v10 User’s Guide
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8.1a
Example – LVDS Differential Pair
Field Overlays
Create Field Plot vs S
Using the project tree, expand the Field Overlay,
Overlay E Field.
Field
Double Click on Mag_E1 to make the field plot visible
Right-Click on Mag_E1 and select Animate
Setup Animation
Swept Variable: S
Click the OK button
The Animation dialog will appear.
Save Project
To save the project:
1. In an Ansoft HFSS window, select the menu item File > Save.
Exiting HFSS
To Exit HFSS:
1. Select the menu item File > Exit
1. If prompted Save the changes
Ansoft High Frequency Structure Simulator v10 User’s Guide
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8.1b
Example – LVDS Differential Pair
Ansoft Designer – Transient Simulation
Launching Ansoft Designer
1.
To access Ansoft Designer, click the Microsoft Start button, select Programs,
Programs and
select the Designer program group. Click Ansoft Designer.
Designer
Opening a New Project
To open a new project:
1. In an Ansoft Designer window, click the On the Standard toolbar, or select
the menu item File > New.
2. From the Project menu, select Insert Circuit Design.
3. Click None button when prompted for Choose Layout Technology.
Note: In this example we are not creating a layout or using
components such as transmission lines that require substrate or stack
up information. If we did, then it is recommended to choose a stack
up from the list or create your own.
Project Manager Window
Ansoft High Frequency Structure Simulator v10 User’s Guide
8.1b-1
8.1b
Example – LVDS Differential Pair
Creating the Circuit
V
50
+
Vin2
4
V
Vout2
V
+
V
3
2
+
Vpos
1
Vout1
Vdiff
0V
V
100
Vin1
50
0V
Vneg
Component Placement
Importing SS-parameters
1. Select the menu item Draw > N-Port or click the
toolbar button.
2. In the N-port data window,
1. Select the Link to file radial button
2. Click the browse button to locate and select your Touchstone file:
hfss_lvds_diffpair.s4p
3. Click the Open button
3. Click the Ok button
Browse button
Ansoft High Frequency Structure Simulator v10 User’s Guide
8.1b-2
8.1b
Example – LVDS Differential Pair
Component Placement – continued
1.
To place the new component, single click with the left mouse button in the
middle of the screen.
1
3
2
4
Placing Resistors, Voltage Sources, and Voltage Probes
1. Click the Components tab in the Project Manager window.
Resistors : Expand Lumped -> Resistors
Voltage Sources: Expand Sources -> Independent Sources
Voltage probes:
probes Expand Probes
Tabs for Project, Components, and Search
Ansoft High Frequency Structure Simulator v10 User’s Guide
8.1b-3
8.1b
Example – LVDS Differential Pair
Component Placement – continued
Place 3 Resistors in the schematic
1. In the Components Tab,
Tab under Lumped -> Resistors,
Resistors double click
Resistors
2. Click the left mouse button 3 times to place 3 resistors in the
schematic.
3. To end the placement, click the right mouse button and select
Finish.
Finish (You can also end the placement by pressing the space bar)
50
1
3
2
4
100
Note: Before placing a component on the schematic use the R key to
rotate. If a component is already placed, use the <ctrl> R key to rotate.
50
Change the value of the resistors
1. Right mouse click the component and then select Properties in the
pull down menu
2. Change the value from 100 to 50,
50 then hit Enter
Note: alternatively, you can left mouse button click on the resistor to
bring up the Properties window (shown below) and change the value
from 100 to 50,
50 then hit Enter
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8.1b
Example – LVDS Differential Pair
Component Placement – continued
50
+
0V
1
3
2
4
100
Place Piecewise Linear Source
1. In the Components Tab, under Sources -> Independent Sources,
Sources
double click on Voltage Source.
Source
2. Left mouse click to place the source in the schematic
3. Press the space bar to finish the placement
50
Source Selection dialog
1. In the Properties Window, click Edit
2. For Name type Vpos
3. For Type,
Type choose Piecewise Linear
4. Click on the Waveform List Box (which is the unmarked column in
between Unit and Description as shown below)
Waveform List Box
Ansoft High Frequency Structure Simulator v10 User’s Guide
8.1b-5
8.1b
Example – LVDS Differential Pair
Component Placement – continued
Piece-wise Waveform List dialog
1. Click on the Radial button next to Enter time/value points.
2. Enter two points:
Time Value
0
0
330ps 1V
Note: make sure you hit
Enter after typing values
1. Click OK to finish
2. Click OK to exit out
of Source Selection
50
+
0V
+
0V
1
3
2
4
100
Adding Second Source
1. Repeat the same steps as adding the first source except change:
1. For Name, type Vneg
2. The data points to:
Time Value
0
0
330ps -1V
50
Ansoft High Frequency Structure Simulator v10 User’s Guide
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8.1b
Example – LVDS Differential Pair
Component Placement – continued
Adding Wiring to connect components
1. Select the menu item Draw -> Wire
2. Place the cursor (which is now an X) over a node and left mouse click once
3. Drag the mouse to the connection node and left mouse click once.
4. Repeat this procedure until the connections below are made
Adding Ground Connections
1. Select the menu item Draw > Ground (alternatively you can select the
toolbar icon)
2. Place 2 ground connections on the ends of the voltage sources
Adding Voltage Probes
1. In the Components tab, expand the Probes.
2. Place 4 Voltage Probes and name them Vin1, Vin2, Vout1, Vout2.
3. Place a Voltage Probe w/Ref. Node across the 100 Ohm resistor and name
it Vdiff
V
50
+
Vin2
2
4
V
Vout2
V
+
V
3
+
Vpos
1
Vout1
Vdiff
0V
V
100
Vin1
50
0V
Vneg
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8.1b-7
8.1b
Example – LVDS Differential Pair
Save Project
To save the project:
1. In an Ansoft HFSS window, select the menu item File > Save As.
2. From the Save As window, type the Filename: lvds_diffpair_transient
3. Click the Save button
Analysis Setup
Creating an Analysis Setup
To create an analysis setup:
1. In the Project Manager window, click the Project tab
2. Select the menu item Circuit -> Add Solution Setup
3. Analysis Setup Window:
1. For Analysis Type,
Type choose Transient Analysis
2. Click Next
3. Analysis Control
1. Length of Analysis: 2ns
2. Maximum Time Step Allowed: 1ps
4. Convolution Control
1. Maximum Sampling Frequency: 8GHz
2. Delta Frequency: 0.01GHz
5. Click Finish
4.
Select the menu item Circuit -> Analyze
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8.1b-8
8.1b
Example – LVDS Differential Pair
Create Reports
Plot Input, Output and Difference waveforms
To create a report:
1. Select the menu item Circuit -> Create Report
2. Create Report Window::
1. Report Type: Standard
2. Display Type: Rectangular Plot
3. Click the OK button
3. Traces Window::
1. Category: Voltage
2. Quantity: V(VPRB:Vin1), V(VPRB:Vin2), V(VPRB:Vout1),
V(VPRB:Vout2), V(VPRB:Diff)
V(VPRB:Diff)
3.
4.
5.
Function: <none>
Click the Add Trace button
Click the Done button
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8.1b-9
8.2a
Segmented Return Path
This example is intended to show you how to create, simulate, and analyze a trace
over a slot in the ground plant using the Ansoft HFSS Design Environment.
5 cm
6 mm
3.4 cm
1 cm
1 cm
3mm
8 mm
4 cm
6 cm
LAYER 1 (SIGNAL 1)
1.3mm
LAYER 2 (BOTTOM SIDE)
Ansoft High Frequency Structure Simulator v10 User’s Guide
Nominal Design:
Board:
Thickness= 1.3mm
εr= 4.5
Trace:
Length= 8.2cm
Termination: 47Ω
47Ω
8.2a -1
8.2a
Ansoft HFSS Design Environment
The following features of the Ansoft HFSS Design Environment are used to create
this passive device model
3D Solid Modeling
Primitives: Box, Rectangles
Boolean Operations: Subtract
Boundaries/Excitations
Ports: Lumped Port, Terminal Lines
Boundary Conditions: Lumped RLC, PML
Analysis
Sweep: Interpolating Sweep
Results
Cartesian and Smith Chart plotting
Field Overlays
Magnitude and Vector Field Plotting
Animation
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8.2a -2
8.2a
Design Review
Before we jump into setting up this device lets review the design.
Trace Width = 3mm
Trace Length= 8.2cm
Dielectric Height= 1.3mm
Port Size/Type= ???
Free Space= PML or Radiation Boundary
Port Size/Type
Since the trace is internal to the model, let’s use a lumped gap source port
Trace Thickness/Material Properties
To start let’s make an engineering assumption that the trace thickness and
conductivity will not have an impact on the performance of the device. This
will speed up the simulation.
Free Space
We should expect some radiation to occur because of the slot in the ground,
however, it should not be very strong. Because there is limited radiation the
separation from the device and the free-space boundary can be kept to a
minimum. The incidence angle of the radiation is unknown, therefore we
should use a PML. The maximum spacing will be ~λ/20 @ 1GHz or about
1.5cm
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8.2a -3
8.2a
Getting Started
Launching Ansoft HFSS
1.
To access Ansoft HFSS, click the Microsoft Start button, select Programs,
Programs and select
the Ansoft, HFSS 10 program group. Click HFSS 10.
10
Setting Tool Options
To set the tool options:
Note: In order to follow the steps outlined in this example, verify that the
following tool options are set :
1. Select the menu item Tools > Options > HFSS Options
2. HFSS Options Window:
1. Click the General tab
Use Wizards for data entry when creating new boundaries:: Checked
Duplicate boundaries with geometry:: Checked
2. Click the OK button
3. Select the menu item Tools > Options > 3D Modeler Options.
Options
4. 3D Modeler Options Window:
1. Click the Operation tab
Automatically cover closed polylines:: Checked
2. Click the Drawing tab
Edit property of new primitives:: Checked
3. Click the OK button
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8.2a
Opening a New Project
To open a new project:
1. In an Ansoft HFSS window, click the On the Standard toolbar, or select
the menu item File > New.
2. From the Project menu, select Insert HFSS Design.
Set Solution Type
To set the solution type:
1. Select the menu item HFSS > Solution Type
2. Solution Type Window:
1. Choose Driven Terminal
2. Click the OK button
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8.2a -5
8.2a
Creating the 3D Model
Set Model Units
To set the units:
1. Select the menu item 3D Modeler > Units
2. Set Model Units:
1. Select Units: cm
2. Click the OK button
Set Default Material
To set the default material:
1. Using the 3D Modeler Materials toolbar, choose Select
2. Select Definition Window:
1. Click the Add Material button
2. View/Edit Material Window:
1. For the Material Name type: My_FR4
2. For the Value of Relative Permittivity type: 4.5
3. Click the OK button
3. Click the OK button
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8.2a
Create Board
To create the board:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the base
rectangle:
dX: 6.0,
6.0 dY: 10.0,
10.0 dZ: -1.3mm,
1.3mm Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Board
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View or press the CTRL+D key
Create Ground
To create ground:
1. Select the menu item Draw > Rectangle
2. Using the coordinate entry fields, enter the box position
X: 0.0,
0.0 Y: 0.0,
0.0 Z: -1.3mm,
1.3mm Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the base
rectangle:
dX: 6.0,
6.0 dY: 10.0,
10.0 dZ: 0.0,
0.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Ground
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
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8.2a
Create Offset Coordinate System
To create an offset Coordinate System:
1. Select the menu item 3D Modeler > Coordinate System > Create >
Relative CS > Offset
2.
Using the coordinate entry fields, enter the origin
X: 0.0,
0.0 Y: 5.0,
5.0 Z: -1.3mm,
1.3mm Press the Enter key
Create Ground Cut Out
To create cut out:
1. Select the menu item Draw > Rectangle
2. Using the coordinate entry fields, enter the box position
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the base
rectangle:
dX: 4.0,
4.0 dY: 6.0mm,
6.0mm dZ: 0.0,
0.0 Press the Enter key
Select Ground & Rectangle1:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Ground, Rectangle1
2. Click the OK button
To complete the ground object:
1. Select the menu item 3D Modeler > Boolean > Subtract
2. Subtract Window
Blank Parts: Ground
Tool Parts: Rectangle1
Clone tool objects before subtract: Unchecked
Click the OK button
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8.2a -8
8.2a
Assign a Perfect E boundary to the Ground
To select the ground:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Ground
2. Click the OK button
To assign the Perfect E boundary
1. Select the menu item HFSS > Boundaries > Assign > Perfect E
2. Perfect E Boundary window
1. Name: PerfE_Ground
2. Click the OK button
Set Working Coordinate System
To set the working coordinate system:
1. Select the menu item 3D Modeler > Coordinate System > Set Working CS
2. Select Coordinate System Window,
1. From the list, select the CS: Global
2. Click the Select button
Create Offset Coordinate System
To create an offset Coordinate System:
1. Select the menu item 3D Modeler > Coordinate System > Create >
Relative CS > Offset
2.
Using the coordinate entry fields, enter the origin
X: 1.0,
1.0 Y: 8.0mm,
8.0mm Z: 0.0,
0.0 Press the Enter key
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8.2a -9
8.2a
Create Trace
To create trace:
1. Select the menu item Draw > Rectangle
2. Using the coordinate entry fields, enter the box position
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the base
rectangle:
dX: 3.0mm,
3.0mm dY: 8.2,
8.2 dZ: 0.0,
0.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Trace
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Assign a Perfect E boundary to the Trace
To select the trace:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Trace
2. Click the OK button
To assign the Perfect E boundary
1. Select the menu item HFSS > Boundaries > Assign > Perfect E
2. Perfect E Boundary window
1. Name: PerfE_Trace
2. Click the OK button
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8.2a -10
8.2a
Set Grid Plane
To set the grid plane:
1. Select the menu item 3D Modeler > Grid Plane > XZ
Create Source
To create source:
1. Select the menu item Draw > Rectangle
2. Using the coordinate entry fields, enter the box position
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the base
rectangle:
dX: 3.0mm,
3.0mm dY: 0.0,
0.0 dZ: -1.3mm,
1.3mm Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Source
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
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8.2a -11
8.2a
Assign Excitation
To select the object Source:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Source
2. Click the OK button
Note:
Note You can also select the object from the Model Tree
To assign lumped port excitation
1. Select the menu item HFSS > Excitations > Assign > Lumped Port
2. Lumped Port : General
1. Name: p1,
p1
2. Resistance: 50
3. Reactance: 0
4. Click the Next button
3. Lumped Port : Terminals
1. Number of Terminals: 1,
2. For T1,
T1 click the Undefined column and select New Line
3. Using the coordinate entry fields, enter the vector position
X: 1.5mm,
1.5mm Y: 0.0,
0.0 Z: -1.3mm,
1.3mm Press the Enter key
4. Using the coordinate entry fields, enter the vertex
dX: 0.0,
0.0 dY: 0.0,
0.0 dZ: 1.3mm,
1.3mm Press the Enter key
5. Click the Finish button
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8.2a -12
8.2a
Create Offset Coordinate System
To create an offset Coordinate System:
1. Select the menu item 3D Modeler > Coordinate System > Create >
Relative CS > Offset
2.
Using the coordinate entry fields, enter the origin
X: 0.0,
0.0 Y: 8.2,
8.2 Z: 0.0,
0.0 Press the Enter key
Create Resistor
To create source:
1. Select the menu item Draw > Rectangle
2. Using the coordinate entry fields, enter the box position
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the base
rectangle:
dX: 3.0mm,
3.0mm dY: 0.0,
0.0 dZ: -1.3mm,
1.3mm Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Resistor
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
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8.2a
Assign Lumped RLC
To select the object Resistor:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Resistor
2. Click the OK button
To assign lumped RLC boundary
1. Select the menu item HFSS > Boundaries> Assign > Lumped RLC
2. Lumped RLC Boundary
1. Name: R,
2. Resistance: Checked
3. Resistance: 47 Ohm
4. For Current Flow Line,
Line click Undefined and select New Line
5. Using the coordinate entry fields, enter the vector position
X: 1.5mm,
1.5mm Y: 0.0,
0.0 Z: -1.3mm,
1.3mm Press the Enter key
6. Using the coordinate entry fields, enter the vertex
dX: 0.0,
0.0 dY: 0.0,
0.0 dZ: 1.3mm,
1.3mm Press the Enter key
7. Click the OK button
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8.2a -14
8.2a
Set Default Material
To set the default material:
1. Using the 3D Modeler Materials toolbar, choose vacuum
Set Working Coordinate System
To set the working coordinate system:
1. Select the menu item 3D Modeler > Coordinate System > Set Working CS
2. Select Coordinate System Window,
1. From the list, select the CS: Global
2. Click the Select button
Create Air
To create the air:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: -1.5,
1.5 Y: -1.5,
1.5 Z: -1.5,
1.5 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the base
rectangle:
dX: 9.0,
9.0 dY: 13.0,
13.0 dZ: 3.0,
3.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Air
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
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8.2a -15
8.2a
Assign a Perfectly Matched Layer (PML)
To select the air:
1. Select the menu item Edit > Select > Faces
2. Select the menu item Edit > Select by name
3. Object Name: Air
1. FaceID:: <Select All>
2. Click the OK button
To assign the PML boundary
1. Select the menu item HFSS > Boundaries > PML Setup Wizard
2. PML Setup Wizard: Cover Objects
1. Select: Create PML Cover Objects on Selected Faces
2. Uniform Layer Thickness: 1cm
3. Create joining corner and edge objects: Checked
4. Click the Next button
3. PML Setup Wizard: Material Parameters
1. Select: PML Objects accept Free Radiation
1. Min Frequency:: 0.01 GHz
2. Click the Next button
2. Review settings on the PML Setup Wizard: Summary page.
3. Click the Finish button
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8.2a -16
8.2a
Create a Face List
Since we are using the PML, we need to create a face list that will be used for the
radiation calculation.
To create a face list
1. Select the menu item Edit > Select > Faces
2. Select the menu item Edit > Select > By Name
3. Select Object Dialog,
1. Select the objects named: Air
2. FaceID:: <Select All>
3. Click the OK button
4. Select the menu item 3D Modeler > List > Create > Face List
Create a Radiation Setup
To define the radiation setup
1. Select the menu item HFSS > Radiation > Insert Far Field Setup > Infinite
Sphere
2.
Far Field Radiation Sphere Setup dialog
Infinite Sphere Tab
1. Name: Radiation
2. Phi: (Start: 0, Stop: 90, Step Size: 90)
3. Theta: (Start: -180, Stop: 180, Step Size: 2)
1. Click the OK button
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8.2a -17
8.2a
Boundary Display
To verify the boundary setup:
1. Select the menu item HFSS > Boundary Display (Solver View)
2. From the Solver View of Boundaries, toggle the Visibility check box for the
boundaries you wish to display.
Note: The background (Perfect Conductor) is displayed as the outer
boundary.
Note: The Perfect Conductors are displayed as the smetal boundary.
Note: Select the menu item, View > Visibility to hide all of the
geometry objects. This makes it easier to see the boundary
3. Click the Close button when you are finished.
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8.2a
Analysis Setup
Creating an Analysis Setup
To create an analysis setup:
1. Select the menu item HFSS > Analysis Setup > Add Solution Setup
2. Solution Setup Window:
1. Click the General tab::
Solution Frequency:: 2.5GHz
Maximum Number of Passes: 20
Maximum Delta S: 0.03
2. Click the Options tab::
Do Lambda Refinement: Checked
Target:: 0.1
User Low-Order Solution Basis: Checked
3. Click the OK button
Adding a Frequency Sweep
To add a frequency sweep:
1. Select the menu item HFSS > Analysis Setup > Add Sweep
1. Select Solution Setup: Setup1
2. Click the OK button
2. Edit Sweep Window:
1. Sweep Type:: Interpolating
2. Click the Setup Interpolation Basis button
Max Solutions:: 20
Error Tolerance:: 0.5%
Click the OK button
3. Extrapolate to DC:: Checked
Minimum Solve Frequency:: 0.01 GHz
4. Snap Magnitude to 0 or 1 at DC: Unchecked
5. Frequency Setup Type:: Linear Step
Stop:: 2.5GHz
Step:: 0.01GHz
6. Click the OK button
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8.2a
Save Project
To save the project:
1. In an Ansoft HFSS window, select the menu item File > Save As.
2. From the Save As window, type the Filename: hfss_seg_gplane
3. Click the Save button
Analyze
Model Validation
To validate the model:
1. Select the menu item HFSS > Validation Check
2. Click the Close button
Note: To view any errors or warning messages, use the Message
Manager.
Analyze
To start the solution process:
1. Select the menu item HFSS > Analyze
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8.2a -20
8.2a
Solution Data
To view the Solution Data:
1. Select the menu item HFSS > Results > Solution Data
To view the Profile:
1. Click the Profile Tab.
To view the Convergence:
1. Click the Convergence Tab
Note: The default view is for convergence is Table.
Table Select
the Plot radio button to view a graphical representations of
the convergence data.
To view the Matrix Data:
1. Click the Matrix Data Tab
Note: To view a real-time update of the Matrix Data, set the
Simulation to Setup1, Last Adaptive
2. Click the Close button
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8.2a -21
8.2a
Create Reports
Create Terminal SS-Parameter Plot vs. Adaptive Pass
Note: If this report is created prior or during the solution process, a real-time update
of the results are displayed
To create a report:
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Terminal S Parameters
2. Display Type: Rectangular
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: Adaptive1
2. Click the Y tab
1. Category: Terminal S Parameter
2. Quantity: St(p1,p1)
3. Function: dB
4. Click the Add Trace button
3. Click the Done button
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8.2a -22
8.2a
Create Terminal ZZ-Parameter Plot – Real/Imaginary
To create a report:
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Terminal S Parameters
2. Display Type: Rectangular
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: Sweep1
2. Domain: Sweep
3. Click the Y tab
1. Category: Terminal Z Parameter
2. Quantity: Zt(p1,p1)
3. Function: Re
4. Click the Add Trace button
5. Category: Terminal Z Parameter
6. Quantity: Zt(p1,p1)
7. Function: Im
8. Click the Add Trace button
4. To add an additional YY-Axis for im(Zt(p1,p1)
1. Select Y1 for Row 2 in Y-axis column and toggle it to Y2
5. Click the Done button
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8.2a
Create Terminal SS-Parameter Plot – Smith Chart
To create a report:
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Terminal S Parameters
2. Display Type: Smith Chart
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: Sweep1
2. Click the Polar tab
1. Category: Terminal S Parameter
2. Quantity: St(p1,p1)
3. Function: <none>
4. Click the Add Trace button
3. Click the Done button
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8.2a -24
8.2a
Matrix Data - Export SS-parameters to a file
To view the Matrix Data:
1. Select the menu item HFSS > Results > Solution Data,
2. Solution Data dialog
1. Click the Matrix Data Tab
2. Simulation: Setup1, Sweep1
3. Click the Export button.
1. Filename: hfss_seg_gplane
2. Save as Type: Touchstone
3. Click the Save button
4. Click the OK button to accept 50ohm reference impedance
4. Click the Close button
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8.2a
Create 3D Polar Far Field Plot
To create a 3D Far Field Plot
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Far Fields
2. Display Type: 3D Polar Plot
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: LastAdaptive
2. Domain: Radiation
3. Click the Mag tab
1. Category: rE
2. Quantity: rETotal
3. Function: dB
4. Click the Add Trace button
4. Click the Done button
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8.2a
Field Overlays
Create Field Overlay
To create a field plot:
1. Confirm you are in Object Select mode by right-clicking in the geometry
window, and selecting from context menu if necessary.
2. Select the menu item Edit > Select > By Name
3. Select Object Dialog,
1. Select the objects named: Board
2. Click the OK button
4. Select the menu item HFSS > Fields > Plot Fields > Mag_E
5. Create Field Plot Window
1. Solution: Setup1 : LastAdaptive
2. Quantity: Mag_E
3. In Volume: All
4. Click the Done button
To modify a Magnitude field plot:
1. Select the menu item HFSS > Fields > Modify Plot Attributes
2. Select Plot Folder Window:
1. Select: E Field
2. Click the OK button
3. E-Field Window:
1. Click the Scale tab
1. Select Use Limits
2. Min: 1
3. Max: 4500
4. Scale: Log
2. Click the Plots Tab
1. Scalar Plot: IsoValSurface
2. Click the Close button
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8.2a
Create Field Overlay
To create a field plot:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Ground
2. Click the OK button
3. Select the menu item HFSS > Fields > Plot Fields > Vector_RealPoynting
4. Create Field Plot Window
1. Solution: Setup1 : LastAdaptive
2. Quantity: Vector_RealPoynting
3. In Volume: All
4. Click the Done button
To modify the attributes of a field plot:
1. Select the menu item HFSS > Fields > Modify Plot Attributes
2. Select Plot Folder Window:
1. Select: Poynting
2. Click the OK button
3. Poynting Window:
1. Click the Scale tab
1. Select Use Limits
2. Min: 0.01
3. Max: 2500
4. Scale: Log
2. Click the Marker/Arrow tab
1. Type: Cylinder
2. Map Size: Unchecked
3. Arrow Tale: Unchecked
4. If real time mode is not checked, click the Apply button.
4. Click the Close button
Exiting HFSS
To Exit HFSS:
1. Select the menu item File > Exit
1. If prompted Save the changes
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8.2a
Ansoft High Frequency Structure Simulator v10 User’s Guide
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8.2b
Ansoft Designer – Transient Simulation
Launching Ansoft Designer
1.
To access Ansoft Designer, click the Microsoft Start button, select Programs,
Programs and
select the Designer program group. Click Ansoft Designer.
Designer
Opening a New Project
To open a new project:
1. In an Ansoft Designer window, click the On the Standard toolbar, or select
the menu item File > New.
2. From the Project menu, select Insert Circuit Design.
3. Click None button when prompted for Choose Layout Technology.
Note: In this example we are not creating a layout or using
components such as transmission lines that require substrate or stack
up information. If we did, then it is recommended to choose a stack
up from the list or create your own.
Project Manager Window
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8.2b -1
8.2b
Creating the Circuit
V
v1
V
v2
1
+
0V
50
Source1
Z=50
P=10000mil
Component Placement
Importing SS-parameters
1. Select the menu item Draw > N-Port or click the
toolbar button.
2. In the N-port data window,
1. Select the Link to file radial button
2. Click the browse button to locate and select your Touchstone file:
hfss_seg_gplane.s1p
3. Click the Open button
3. Click the Ok button
Browse
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8.2b -2
8.2b
Component Placement – continued
1.
To place the new component, single click with the left mouse button in the
middle of the screen.
1
Placing Resistors, Voltage Sources, and Voltage Probes
1. Click the Components tab in the Project Manager window.
Resistors : Expand Lumped -> Resistors
Voltage Sources: Expand Sources -> Independent Sources
Voltage probes:
probes Expand Probes
Tabs for Project, Components, and Search
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8.2b -3
8.2b
Component Placement – continued
Place a Resistor in the schematic
1. In the Components Tab,
Tab under Lumped -> Resistors,
Resistors double click
Resistor
2. Click the left mouse button once to place a resistor in the schematic.
3. To end the placement, click the right mouse button and select
Finish.
Finish (You can also end the placement by pressing the space bar)
1
100
Change the value of the resistor
1. Right mouse click the component and then select Properties in the
pull down menu
2. Change the value from 100 to 50,
50 then hit Enter
Note: alternatively, you can left mouse button click on the resistor to
bring up the Properties window (shown below) and change the value
from 100 to 50,
50 then hit Enter
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8.2b
Component Placement – continued
Place a Coaxial Cable in the schematic
1. In the Components Tab,
Tab under Coaxial Cable,
Cable double click Coaxial
Cable, K
2. Click the left mouse button once to place a coaxial cable in the
schematic.
3. Press the space bar to finish the placement
1
50
Z=50
P=10000mil
Change the physical length of the coaxial cable
1. Right mouse click the component and then select Properties in the
pull down menu
2. Change the value of P to 10000mil,
10000mil then hit Enter
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8.2b
Component Placement – continued
Place Piecewise Linear Source
1. In the Components Tab, under Sources -> Independent Sources,
Sources
double click on Voltage Source.
Source
2. Left mouse click to place the source in the schematic
3. Press the space bar to finish the placement
1
+
0V
50
Source1
Z=50
P=10000mil
Source Selection dialog
1. In the Properties Window, click Edit
2. For Name type Vin
3. For Type,
Type choose Piecewise Linear
4. Click on the Waveform List Box (which is the unmarked column in
between Unit and Description as shown below)
Waveform List Box
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8.2b -6
8.2b
Component Placement – continued
1.
Piece-wise Waveform List dialog
1. Click on the Radial button next to Enter time/value points.
2. Enter two points:
Time Value
0
0
1ns
1V
Note: make sure you hit Enter after typing values
1. Click the OK button
Click the OK button
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8.2b -7
8.2b
Component Placement – continued
Adding Wiring to connect components
1. Select the menu item Draw -> Wire
2. Place the cursor (which is now an X) over a node and left mouse click once
3. Drag the mouse to the connection node and left mouse click once.
4. Repeat this procedure until the connections below are made
Adding Ground Connections
1. Select the menu item Draw > Ground (alternatively you can select the
toolbar icon)
2. Place a ground connection on the end of the voltage source
Adding Voltage Probes
1. In the Components tab, expand the Probes.
2. Place 2 Voltage Probes and name them v1, v2.
V
v1
V
v2
1
+
0V
50
Source1
Ansoft High Frequency Structure Simulator v10 User’s Guide
Z=50
P=10000mil
8.2b -8
8.2b
Creating the Circuit
Save Project
2.
To save the project:
In an Ansoft Designer window, select the menu item File > Save As.
From the Save As window, type the Filename: hfss_seg_gplane_tdr
3.
Click the Save button
1.
Analysis Setup
Creating an Analysis Setup
To create an analysis setup:
1. In the Project Manager window, click the Project tab
2. Select the menu item Circuit -> Add Solution Setup
3. Analysis Setup Window:
1. For Analysis Type,
Type choose Transient Analysis
2. Click Next
3. Analysis Control
1. Length of Analysis: 8ns
2. Maximum Time Step Allowed: 1ps
4. Convolution Control
1. Maximum Sampling Frequency: 2.5GHz
2. Delta Frequency: 0.01GHz
5. Click Finish
4. Select the menu item Circuit -> Analyze
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8.2b -9
8.2b
Create Reports
Plot Input, Output waveforms
To create a report:
1. Select the menu item Circuit -> Create Report
2. Create Report Window::
1. Report Type: Standard
2. Display Type: Rectangular Plot
3. Click the OK button
3. Traces Window::
1. Category: Voltage
2. Quantity: V(VPRB:V1), V(VPRB:V2)
3. Function: <none>
4. Click the Add Trace button
5. Click the Done button
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8.2b -10
8.2b
Create Reports
Plot TDR
To create a report:
1. Select the menu item Circuit -> Create Report
2. Create Report Window::
1. Report Type: Standard
2. Display Type: Rectangular Plot
3. Click the OK button
3. Click on Output Variables button to create TDR equation
1. Name: type TDR
2. Expression: V(VPRB:v2)/(V(VPRB:v1)V(VPRB:v2)/(V(VPRB:v1)-V(VPRB:v2))*50
Note: To create the above expression, follow these steps:
1. Category: Voltage
2. Quantity: V(VPRB:v2)
3. Click Insert Quantity into Expression button
4. Type / then type (
5. Quantity: V(VPRB:v1)
6. Click Insert Quantity into Expression button
7. Type 8. Quantity: V(VPRB:v2)
9. Click Insert Quantity into Expression button
10. Type )
11. Type * 50
3.
4.
Click the Add button
Click the Done button
Traces Window::
Category: Output Variables
Quantity: TDR
Function: <none>
Click the Add Trace button
Click the Done button (see next page for TDR plot)
Ansoft High Frequency Structure Simulator v10 User’s Guide
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8.2b
Ansoft High Frequency Structure Simulator v10 User’s Guide
8.2b -12
8.3
Example – Non-Ideal Planes
Non-Ideal Ground Plane
This example is intended to show you how to create, simulate, and analyze nonideal ground planes using the Ansoft HFSS Design Environment.
trace1
top_gnd
Via
bot_gnd
trace2
Nominal Design:
Ground:
Thickness = 0.1 mm
Board:
Thickness = 0.9 mm
εr = 1
Trace:
Length = 10 mm
Width = 1 mm
Thickness = 0.1 mm
Via:
Diameter = 1 mm
Height = 0.9 mm
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8.3-1
8.3
Example – Non-Ideal Planes
Ansoft HFSS Design Environment
The following features of the Ansoft HFSS Design Environment are used to
create this passive device model
3D Solid Modeling
Primitives: Box, Rectangles, Cylinders
Boolean Operations: Subtract, Unite, Duplicate
Boundary
Boundary Conditions: Perfect H/Natural
Excitations
Ports: Lumped Gap Source Port, Terminal Lines
Analysis
Sweep:: Fast Frequency
Results
Cartesian plotting
Fields
Fast Frequency Sweep/Field Plots
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8.3
Example – Non-Ideal Planes
Design Review
Before we jump into setting up this device lets review the design.
Port Size/Type= ???
Free Space= ???
Port Size/Type
Since the trace is internal to the model, lets use a lumped gap source port
Trace Thickness/Material Properties
To start with perfect conductor, lets make an engineering assumption that the
trace conductivity will not have an impact on the performance of the device.
This will speed up the simulation.
Free Space
Since we are only interested in the modes that occur between the ground
planes, we can use a Perfect H or open boundary condition. We should
expect to get the same answer using an Open(Perfect H) or
matched(Radiation) boundary. The radiation boundary takes longer to solve
since it requires a complex solve.
You do need to use some caution when using Perfect H boundary
conditions in place of radiation boundaries. The Perfect H and
Symmetry Perfect H are mathematically equivalent. Therefore if you
are simulating a subsection of a larger geometry, you have the
potential to create modes that are the result of the boundary condition
or non-physical. In our example, the Perfect H is applied to the outside
of the model and not along any symmetry planes.
It should be noted that the Perfect H boundary condition can be used
with the Driven and Eigenmode solver. The Radiation boundary is
only supported by the Driven Solution.
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8.3
Example – Non-Ideal Planes
Getting Started
Launching Ansoft HFSS
1.
To access Ansoft HFSS, click the Microsoft Start button, select Programs,
Programs and select
the Ansoft HFSS 10 program group. Click HFSS 10.
10
Setting Tool Options
To set the tool options:
Note: In order to follow the steps outlined in this example, verify that the
following tool options are set :
1. Select the menu item Tools > Options > HFSS Options
2. HFSS Options Window:
1. Click the General tab
Use Wizards for data entry when creating new boundaries:: Checked
Duplicate boundaries with geometry:: Checked
2. Click the OK button
3. Select the menu item Tools > Options > 3D Modeler Options.
Options
4. 3D Modeler Options Window:
1. Click the Operation tab
Automatically cover closed polylines:: Checked
2. Click the Drawing tab
Edit property of new primitives:: Checked
3. Click the OK button
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8.3
Example – Non-Ideal Planes
Opening a New Project
To open a new project:
1. In an Ansoft HFSS window, click the On the Standard toolbar, or select
the menu item File > New.
2. From the Project menu, select Insert HFSS Design.
Set Solution Type
To set the solution type:
1. Select the menu item HFSS > Solution Type
2. Solution Type Window:
1. Choose Driven Terminal
2. Click the OK button
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8.3
Example – Non-Ideal Planes
Creating the 3D Model
Set Model Units
To set the units:
1. Select the menu item 3D Modeler > Units
2. Set Model Units:
1. Select Units: mm
2. Click the OK button
Set Default Material
To set the default material:
1. Using the 3D Modeler Materials toolbar, choose Select
2. Select Definition Window:
1. Type pec in the Search by Name field
2. Click the OK button
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8.3
Example – Non-Ideal Planes
Create Trace
To create the trace:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: -0.5,
0.5 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the base
rectangle:
dX: 1.0,
1.0 dY: -10.0,
10.0 dZ: 0.1,
0.1 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Trace
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View. Or press the CTRL+D key
Create Via Pad
To create the via pad:
1. Select the menu item Draw > Cylinder
2. Using the coordinate entry fields, enter the cylinder position
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the radius:
dX: 0.75,
0.75 dY: 0.0,
0.0 dZ: 0.0,
0.0 Press the Enter key
4. Using the coordinate entry fields, enter the height:
dX: 0.0,
0.0 dY: 0.0,
0.0 dZ: 0.1,
0.1 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Via_pad
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
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8.3
Example – Non-Ideal Planes
Group the Trace & Via Pad
To group the dipole arms:
1. Select the menu item Edit > Select All Visible. Or press the CTRL+A key.
2. Select the menu item, 3D Modeler > Boolean > Unite
Create Offset Coordinate System
To create an offset Coordinate System:
1. Select the menu item 3D Modeler > Coordinate System > Create >
Relative CS > Offset
2.
Using the coordinate entry fields, enter the origin
X: 0.0,
0.0 Y: 0.0,
0.0 Z: -0.2,
0.2 Press the Enter key
Create Ground 1
To create ground:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: -10.0,
10.0 Y: -20.0,
20.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the base
rectangle:
dX: 20.0,
20.0 dY: 40.0,
40.0 dZ: 0.1,
0.1 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Ground
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Ansoft High Frequency Structure Simulator v10 User’s Guide
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8.3
Example – Non-Ideal Planes
Create AntiAnti-Pad
To create the antianti-pad:
1. Select the menu item Draw > Cylinder
2. Using the coordinate entry fields, enter the cylinder position
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the radius:
dX: 1.0,
1.0 dY: 0.0,
0.0 dZ: 0.0,
0.0 Press the Enter key
4. Using the coordinate entry fields, enter the height:
dX: 0.0,
0.0 dY: 0.0,
0.0 dZ: 0.1,
0.1 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Antipad
3. Click the OK button
Select Ground & Antipad:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Antipad, Ground
2. Click the OK button
To complete the ground object:
1. Select the menu item 3D Modeler > Boolean > Subtract
2. Subtract Window
Blank Parts: Ground
Tool Parts: Antipad
Clone tool objects before subtract: Unchecked
Click the OK button
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8.3
Example – Non-Ideal Planes
Set Working Coordinate System
To set the working coordinate system:
1. Select the menu item 3D Modeler > Coordinate System > Set Working CS
2. Select Coordinate System Window,
1. From the list, select the CS: Global
2. Click the Select button
Create Offset Coordinate System
To create an offset Coordinate System:
1. Select the menu item 3D Modeler > Coordinate System > Create >
Relative CS > Offset
2.
Using the coordinate entry fields, enter the origin
X: -0.5,
0.5 Y: -10.0,
10.0 Z: 0.0,
0.0 Press the Enter key
Set Grid Plane
To set the grid plane:
1. Select the menu item 3D Modeler > Grid Plane > XZ
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8.3
Example – Non-Ideal Planes
Create Source
To create source:
1. Select the menu item Draw > Rectangle
2. Using the coordinate entry fields, enter the box position
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the base
rectangle:
dX: 1.0,
1.0 dY: 0.0,
0.0 dZ: -0.1,
0.1 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Source
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
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8.3
Example – Non-Ideal Planes
Assign Excitation
To select the object Source:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Source
2. Click the OK button
Note:
Note You can also select the object from the Model Tree
To assign lumped port excitation
1. Select the menu item HFSS > Excitations > Assign > Lumped Port
2. Lumped Port : General
1. Name: p1,
p1
2. Resistance: 50
3. Reactance: 0
4. Click the Next button
3. Lumped Port : Terminals
1. Number of Terminals: 1,
2. For T1,
T1 click the Undefined column and select New Line
3. Using the coordinate entry fields, enter the vector position
X: 0.5,
0.5 Y: 0.0,
0.0 Z: -0.1,
0.1 Press the Enter key
4. Using the coordinate entry fields, enter the vertex
dX: 0.0,
0.0 dY: 0.0,
0.0 dZ: 0.1,
0.1 Press the Enter key
5. Click the Finish button
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8.3-12
8.3
Example – Non-Ideal Planes
Set Working Coordinate System
To set the working coordinate system:
1. Select the menu item 3D Modeler > Coordinate System > Set Working CS
2. Select Coordinate System Window,
1. From the list, select the CS: Global
2. Click the Select button
Create Offset Coordinate System
To create an offset Coordinate System:
1. Select the menu item 3D Modeler > Coordinate System > Create >
Relative CS > Offset
2.
Using the coordinate entry fields, enter the origin
X: 0.0,
0.0 Y: 0.0,
0.0 Z: -0.45,
0.45 Press the Enter key
Duplicate Objects
To duplicate the existing objects:
1. Select the menu item Edit > Select All Visible. Or press the CTRL+A key.
2. Select the menu item, Edit > Duplicate > Around Axis.
1. Axis: X
2. Angle: 180
3. Total Number: 2
4. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Set Grid Plane
To set the grid plane:
1. Select the menu item 3D Modeler > Grid Plane > XY
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8.3
Example – Non-Ideal Planes
Set Working Coordinate System
To set the working coordinate system:
1. Select the menu item 3D Modeler > Coordinate System > Set Working CS
2. Select Coordinate System Window,
1. From the list, select the CS: Global
2. Click the Select button
Create Via
To create the via:
1. Select the menu item Draw > Cylinder
2. Using the coordinate entry fields, enter the cylinder position
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the radius:
dX: 0.5,
0.5 dY: 0.0,
0.0 dZ: 0.0,
0.0 Press the Enter key
4. Using the coordinate entry fields, enter the height:
dX: 0.0,
0.0 dY: 0.0,
0.0 dZ: -0.9,
0.9 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Via
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Create Offset Coordinate System
To create an offset Coordinate System:
1. Select the menu item 3D Modeler > Coordinate System > Create >
Relative CS > Offset
2.
Using the coordinate entry fields, enter the origin
X: -5.0,
5.0 Y: -10.0,
10.0 Z: -0.2,
0.2 Press the Enter key
Ansoft High Frequency Structure Simulator v10 User’s Guide
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8.3
Example – Non-Ideal Planes
Create Ground Via
To create the Ground Via:
1. Select the menu item Draw > Cylinder
2. Using the coordinate entry fields, enter the cylinder position
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the radius:
dX: 0.5,
0.5 dY: 0.0,
0.0 dZ: 0.0,
0.0 Press the Enter key
4. Using the coordinate entry fields, enter the height:
dX: 0.0,
0.0 dY: 0.0,
0.0 dZ: -0.5,
0.5 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Via_GND
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Set Working Coordinate System
To set the working coordinate system:
1. Select the menu item 3D Modeler > Coordinate System > Set Working CS
2. Select Coordinate System Window,
1. From the list, select the CS: Global
2. Click the Select button
Set Default Material
To set the default material:
1. Using the 3D Modeler Materials toolbar, choose vacuum
Ansoft High Frequency Structure Simulator v10 User’s Guide
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8.3
Example – Non-Ideal Planes
Create Board
To create the board:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: -10.0,
10.0 Y: -20.0,
20.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the base
rectangle:
dX: 20.0,
20.0 dY: 40.0,
40.0 dZ: -0.9,
0.9 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Board
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Create Air
To create the Air:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: -15.0,
15.0 Y: -25.0,
25.0 Z: -5.0,
5.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the base
rectangle:
dX: 30.0,
30.0 dY: 50.0,
50.0 dZ: 10.0,
10.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Air
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
2.
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8.3
Example – Non-Ideal Planes
Assign Perfect H/Natural Boundaries
To select the object Air:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Air
2. Click the OK button
To assign Perfect H Boundary
1. Select the menu item HFSS > Boundaries> Assign > Perfect H…
2. Click the OK button
Boundary Display
To verify the boundary setup:
1. Select the menu item HFSS > Boundary Display (Solver View)
2. From the Solver View of Boundaries, toggle the Visibility check box for the
boundaries you wish to display.
Note: The Perfect Conductors are displayed as the smetal boundary.
Note: Select the menu item, View > Visibility to hide all of the
geometry objects. This makes it easier to see the boundary
3. Click the Close button when you are finished.
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8.3
Example – Non-Ideal Planes
Analysis Setup
Creating an Analysis Setup
To create an analysis setup:
1. Select the menu item HFSS > Analysis Setup > Add Solution Setup
2. Solution Setup Window:
1. Click the General tab::
Solution Frequency:: 10.0GHz
Maximum Number of Passes: 20
Maximum Delta S: 0.02
2. Click the Options tab::
Do Lambda Refinement: Checked
Target:: 0.05
Use Low-Order Solution Basis: Checked
3. Click the OK button
Adding a Frequency Sweep
To add a frequency sweep:
1. Select the menu item HFSS > Analysis Setup > Add Sweep
1. Select Solution Setup: Setup1
2. Click the OK button
2. Edit Sweep Window:
1. Sweep Type:: Fast
2. Frequency Setup Type:: Linear Count
Start: 0.1GHz
Stop:: 10.0GHz
Count:: 991
Save Fields: Checked
3. Click the OK button
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8.3
Example – Non-Ideal Planes
Save Project
To save the project:
1. In an Ansoft HFSS window, select the menu item File > Save As.
2. From the Save As window, type the Filename: hfss_nonidealgnd
3. Click the Save button
Analyze
Model Validation
To validate the model:
1. Select the menu item HFSS > Validation Check
2. Click the Close button
Note: To view any errors or warning messages, use the Message
Manager.
Analyze
To start the solution process:
1. Select the menu item HFSS > Analyze
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8.3
Example – Non-Ideal Planes
Solution Data
To view the Solution Data:
1. Select the menu item HFSS > Results > Solution Data
To view the Profile:
1. Click the Profile Tab.
To view the Convergence:
1. Click the Convergence Tab
Note: The default view is for convergence is Table.
Table Select
the Plot radio button to view a graphical representations of
the convergence data.
To view the Matrix Data:
1. Click the Matrix Data Tab
Note: To view a real-time update of the Matrix Data, set the
Simulation to Setup1, Last Adaptive
2. Click the Close button
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8.3
Example – Non-Ideal Planes
Create Reports
Create Terminal SS-Parameter Plot vs. Adaptive Pass
Note: If this report is created prior or during the solution process, a real-time
update of the results are displayed
To create a report:
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Terminal S Parameters
2. Display Type: Rectangular
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: Adaptive1
2. Click the X tab
1. Use Primary Sweep:: Unchecked
2. Category: Variables
3. Quantity:: Pass
3. Click the Y tab
1. Category: Terminal S Parameter
2. Quantity: St(p1,p1) and St(p1, p2)
3. Function: dB
4. Click the Add Trace button
4. Click the Done button
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8.3
Example – Non-Ideal Planes
Create Terminal S21 Plot vs Frequency
To create a report:
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Terminal S Parameters
2. Display Type: Rectangular
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: Sweep1
2. Domain: Sweep
3. Click the Y tab
1. Category: Terminal S Parameter
2. Quantity: St(p1,p2)
3. Function: dB
4. Click the Add Trace button
4. Click the Done button
To add data marker to the Plots
1. Select the menu item Report2D > Data Marker
2. Move cursor to the resonant points on the plotting curve and click the left
mouse button
3. When you are finished placing markers at the resonances, right-click the
mouse and select Exit Marker Mode.
Mode
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Example – Non-Ideal Planes
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Example – Non-Ideal Planes
Field Overlays
Create Field Overlay
Select the Relative CS XY Plane
1. Using the Model Tree, expand Planes
1. Select Relative CS3 XY
Note: Relative CS3 XY plane is the plane between the two Ground
planes.
2. Select the menu item HFSS > Fields > Fields > E > Mag_E
3. Create Field Plot Window
1. Solution: Setup1 : Sweep1
2. Intrinsic Variables: Freq: 1.9GHz; Phase: 0deg
3. Quantity: Mag_E
4. In Volume: Board
5. Click the Done button
To modify the attributes of a field plot:
1. Select the menu item HFSS > Fields > Modify Plot Attributes
2. Select Plot Folder Window:
1. Select: E Field
2. Click the OK button
3. E-Field Window:
1. Click the Scale tab
1. Select Use Limits
2. Min: 5
3. Max: 3500
4. Scale: Log
2. Click the Plots Tab
1. Scalar Plot: Fringe
2. Click the Close button
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Example – Non-Ideal Planes
Create Field Overlay – Additional Frequency Points
To modify the Frequency of a field plot:
1. Select the menu item HFSS > Fields > Modify Plot
2. Select Plot Folder Window:
1. Select: E Field
2. Click the OK button
3. Create Field Plot Window
1. Solution: Setup1 : Sweep1
2. Freq: 6.84 GHz
Exiting HFSS
To Exit HFSS:
1. Select the menu item File > Exit
1. If prompted Save the changes
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Example – Return Path
Return Path
This example is intended to show you how to create, simulate, and analyze the
return path examples used in the Boundary/Excitations Overview for the Ansoft
HFSS Design Environment.
Port2
Port3
Port1
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Example – Return Path
Getting Started
Launching Ansoft HFSS
1.
To access Ansoft HFSS, click the Microsoft Start button, select Programs,
Programs and select
the Ansoft > HFSS 10 program group. Click HFSS 10.
10
Setting Tool Options
To set the tool options:
Note: In order to follow the steps outlined in this example, verify that the
following tool options are set :
1. Select the menu item Tools > Options > HFSS Options
2. HFSS Options Window:
1. Click the General tab
Use Wizards for data entry when creating new boundaries:: Checked
Duplicate boundaries with geometry:: Checked
2. Click the OK button
3. Select the menu item Tools > Options > 3D Modeler Options.
Options
4. 3D Modeler Options Window:
1. Click the Operation tab
Automatically cover closed polylines:: Checked
2. Click the Drawing tab
Edit property of new primitives:: Checked
3. Click the OK button
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Example – Return Path
Opening a New Project
To open a new project:
1. In an Ansoft HFSS window, click the On the Standard toolbar, or select
the menu item File > New.
2. From the Project menu, select Insert HFSS Design.
Set Solution Type
To set the solution type:
1. Select the menu item HFSS > Solution Type
2. Solution Type Window:
1. Choose Driven Terminal
2. Click the OK button
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Example – Return Path
Creating the 3D Model
Set Model Units
To set the units:
1. Select the menu item 3D Modeler > Units
2. Set Model Units:
1. Select Units: mm
2. Click the OK button
Set Default Material
To set the default material:
1. Using the 3D Modeler Materials toolbar, choose Select
2. Select Definition Window:
1. Type pec in the Search by Name field
2. Click the OK button
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Example – Return Path
Create Conductor
To create the conductor:
1. Select the menu item Draw > Line
2. Using the coordinate entry fields, enter the vertex point:
X: -5.0,
5.0 Y: -0.24,
0.24 Z: 0.1,
0.1 Press the Enter key
3. Using the coordinate entry fields, enter the vertex point:
X: -1.0,
1.0 Y: -0.24,
0.24 Z: 0.1,
0.1 Press the Enter key
4. Using the coordinate entry fields, enter the vertex point:
X: -1.0,
1.0 Y: -0.24,
0.24 Z: 1.1,
1.1 Press the Enter key
5. Using the coordinate entry fields, enter the vertex point:
X: 0.0,
0.0 Y: -0.24,
0.24 Z: 1.1,
1.1 Press the Enter key
6. Using the mouse, right-click and select Done
7. Click the OK button when the Properties dialog appears
To set the grid plane:
1. Select the menu item 3D Modeler > Grid Plane > YZ
To create conductor profile:
1. Select the menu item Draw > Rectangle
2. Using the coordinate entry fields, enter the box position
X: -5.0,
5.0 Y: -0.3,
0.3 Z: 0.1,
0.1 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the base rectangle:
dX: 0.0,
0.0 dY: 0.12,
0.12 dZ: 0.02,
0.02 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Cond
3. Click the OK button
To Sweep the profile:
1. Select the menu item Edit > Select All Visible. Or press the CTRL+A key
2. Select the menu item Draw > Sweep > Along Path
3. Click the OK button when the Sweep along path dialog appears
To fit the view:
1. Select the menu item View > Fit All > Active View.
Or press the CTRL+D key
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Example – Return Path
Duplicate Conductor
To select the object:
1. Select the menu item Edit > Select All Visible.
To duplicate the conductor:
1. Select the menu item, Edit > Duplicate > Along Line.
1. First Point: X:: 0.0, Y:: 0.0, Z:: 0.0 Press the Enter key
2. Second Point: dX:: 0.0,
0.0 dY:: 0.24,
0.24 dZ:: 0.0 Press the Enter key
3. Total Number: 3
4. Click the OK button
Mirror Conductor
To duplicate the existing objects:
1. Select the menu item Edit > Select All Visible. Or press the CTRL+A key.
2. Select the menu item, Edit > Duplicate > Mirror.
1. Input the anchor point of the mirror plane:
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
2. Input the target point of the vector normal to the mirror plane:
dX: 1.0,
1.0 dY: 0.0,
0.0 dZ: 0.0,
0.0 Press the Enter key
Group Conductors
To group the conductors:
1. Select the menu item Edit > Select All Visible.
2. Select the menu item, 3D Modeler > Boolean > Unite
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Example – Return Path
Create Ground
To create the ground:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: -5.0,
5.0 Y: -1.0,
1.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the base
rectangle:
dX: 4.0,
0.02,
4.0 dY: 2.0,
2.0 dZ: -0.02
0.02 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: GND
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Mirror Ground
To select the object GND:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: GND
2. Click the OK button
To mirror the ground:
1. Select the menu item, Edit > Duplicate > Mirror.
1. Input the anchor point of the mirror plane:
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
2. Input the target point of the vector normal to the mirror plane:
dX: 1.0,
1.0 dY: 0.0,
0.0 dZ: 0.0,
0.0 Press the Enter key
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Example – Return Path
Set Grid Plane
To set the grid plane:
1. Select the menu item 3D Modeler > Grid Plane > YZ
Create Source
To create source:
1. Select the menu item Draw > Rectangle
2. Using the coordinate entry fields, enter the box position
X: 5.0,
0.06,
5.0 Y: -0.06
0.06 Z: 0.1,
0.1 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the base
rectangle:
dX: 0.0,
0.0 dY: 0.12,
0.12 dZ: -0.1,
0.1 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Source
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
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Example – Return Path
Assign Excitation
To select the object Source:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Source
2. Click the OK button
Note:
Note You can also select the object from the Model Tree
To assign lumped port excitation
1. Select the menu item HFSS > Excitations > Assign > Lumped Port
2. Lumped Port : General
1. Name: p1,
p1
2. Resistance: 50
3. Reactance: 0
4. Click the Next button
3. Lumped Port : Terminals
1. Number of Terminals: 1,
2. For T1,
T1 click the Undefined column and select New Line
3. Using the coordinate entry fields, enter the vector position
X: 5.0,
5.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
4. Using the coordinate entry fields, enter the vertex
dX: 0.0,
0.0 dY: 0.0,
0.0 dZ: 0.1,
0.1 Press the Enter key
5. Click the Next button
6. Click the Finish button
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Example – Return Path
Create Source2
To select Source:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Source
2. Click the OK button
To mirror the source:
1. Select the menu item, Edit > Duplicate > Mirror.
1. Input the anchor point of the mirror plane:
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
2. Input the target point of the vector normal to the mirror plane:
dX: 1.0,
1.0 dY: 0.0,
0.0 dZ: 0.0,
0.0 Press the Enter key
Create Source3
To select Source:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Source_1
2. Click the OK button
To mirror the source:
1. Select the menu item, Edit > Duplicate > Mirror.
1. Input the anchor point of the mirror plane:
X: 0.0,
0.0 Y: 0.12,
0.12 Z: 0.0,
0.0 Press the Enter key
2. Input the target point of the vector normal to the mirror plane:
dX: 0.0,
0.0 dY: 1.0,
1.0 dZ: 0.0,
0.0 Press the Enter key
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Example – Return Path
Add New Material
To add a new material:
1. Using the 3D Modeler Materials toolbar, choose Select
2. From the Select Definition window, click the Add Material button
3. View/Edit Material Window:
1. Material Name: My_FR4
2. Relative Permittivity: 4.4
3. Click the OK button
4. Click the OK button
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Example – Return Path
Set Grid Plane
To set the grid plane:
1. Select the menu item 3D Modeler > Grid Plane > XY
Create Substrate
To create substrate:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: -5.0,
5.0 Y: -1.0,
1.0 Z: 0.0, Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the base rectangle:
dX: 4.0,
4.0 dY: 2.0,
2.0 dZ: 0.1, Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Substrate
To set the transparency:
1. Select the Attribute tab from the Properties window.
2. Click the button for Transparency
1. Move the slide bar to 0.8 (Opaque=0, Transparency=1)
2. Click the OK button
3. Click the OK button
Mirror Substrate
To select the object substrate:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Substrate
2. Click the OK button
To mirror the ground:
1. Select the menu item, Edit > Duplicate > Mirror.
1. Input the anchor point of the mirror plane:
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
2. Input the target point of the vector normal to the mirror plane:
dX: 1.0,
1.0 dY: 0.0,
0.0 dZ: 0.0,
0.0 Press the Enter key
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Example – Return Path
Set Default Material
To set the default material:
1. Using the 3D Modeler Materials toolbar, choose vacuum
Create Air
To create the Air:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: -5.2,
5.2 Y: -2.0,
2.0 Z: -0.2,
0.2 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the base
rectangle:
dX: 10.4,
10.4 dY: 4.0,
4.0 dZ: 2.0,
2.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Air
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Assign Radiation
To select the object Air:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Air
2. Click the OK button
To assign Radiation Boundary
1. Select the menu item HFSS > Boundaries> Assign > Radiation
2. Click the OK button
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Example – Return Path
Boundary Display
To verify the boundary setup:
1. Select the menu item HFSS > Boundary Display (Solver View)
2. From the Solver View of Boundaries, toggle the Visibility check box for the
boundaries you wish to display.
Note: The Perfect Conductors are displayed as the smetal boundary.
Note: Select the menu item, View > Visibility to hide all of the
geometry objects. This makes it easier to see the boundary
3. Click the Close button when you are finished.
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Example – Return Path
Analysis Setup
Creating an Analysis Setup
To create an analysis setup:
1. Select the menu item HFSS > Analysis Setup > Add Solution Setup
2. Solution Setup Window:
1. Click the General tab::
Solution Frequency:: 15.1GHz
Maximum Number of Passes: 20
Maximum Delta S: 0.03
2. Click the Options tab::
Do Lambda Refinement: Checked
Target:: 0.05
User Low-Order Solution Basis: Checked
3. Click the OK button
Adding a Frequency Sweep
To add a frequency sweep:
1. Select the menu item HFSS > Analysis Setup > Add Sweep
1. Select Solution Setup: Setup1
2. Click the OK button
2. Edit Sweep Window:
1. Sweep Type:: Fast
2. Frequency Setup Type:: Linear Count
Start: 0.1GHz
Stop:: 15.1GHz
Count:: 301
Save Fields: Checked
3. Click the OK button
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Example – Return Path
Save Project
To save the project:
1. In an Ansoft HFSS window, select the menu item File > Save As.
2. From the Save As window, type the Filename: hfss_returnpath
3. Click the Save button
Analyze
Model Validation
To validate the model:
1. Select the menu item HFSS > Validation Check
2. Click the Close button
Note: To view any errors or warning messages, use the Message
Manager.
Analyze
To start the solution process:
1. Select the menu item HFSS > Analyze All
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Example – Return Path
Solution Data
To view the Solution Data:
1. Select the menu item HFSS > Results > Solution Data
To view the Profile:
1. Click the Profile Tab.
To view the Convergence:
1. Click the Convergence Tab
Note: The default view is for convergence is Table.
Table Select
the Plot radio button to view a graphical representations of
the convergence data.
To view the Matrix Data:
1. Click the Matrix Data Tab
Note: To view a real-time update of the Matrix Data, set the
Simulation to Setup1, Last Adaptive
2. Click the Close button
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Example – Return Path
Create Reports
Create Terminal SS-Parameter Plot vs. Adaptive Pass
Note: If this report is created prior or during the solution process, a real-time
update of the results are displayed
To create a report:
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Terminal S Parameters
2. Display Type: Rectangular
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: Adaptive1
2. Click the Y tab
1. Category: Terminal S Parameter
2. Quantity: St(p1,p1), St(p1, p2), St(p1, p3)
3. Function: dB
4. Click the Add Trace button
3. Click the Done button
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Example – Return Path
Create Terminal SS-Parameter Plot vs Frequency
To create a report:
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Terminal S Parameters
2. Display Type: Rectangular
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: Sweep1
2. Domain: Sweep
3. Click the Y tab
1. Category: Terminal S Parameter
2. Quantity: St(p1,p1), St(p1, p2), St(p1, p3)
3. Function: dB
4. Click the Add Trace button
4. Click the Done button.
No DC
Return Path
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Example – Return Path
Return Path – Add a DC Return Path
We will continue our investigation by adding a connection between the two
ground planes. The DC return path will be the path of least resistance.
DC
Return Path
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Example – Return Path
Copy the Design
To copy the entire design:
1. Using the project manager,
1. Right-click on HFSSModel1,
HFSSModel1 and choose Copy
2. Using the project manager,
1. Right-click on hfss_returnpath,
hfss_returnpath and choose Paste
Open the 3D Model Editor
To open the 3D Model Editor:
1. Using the project manager,
1. Right-click on HFSSModel2 and choose 3D Model Editor
Set Default Material
To set the default material:
1. Using the 3D Modeler Materials toolbar, choose pec
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Example – Return Path
Create DC Path
To create the DC path:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: -1.0,
1.0 Y: 1.0,
1.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the base
rectangle:
dX: 2.0,
2.0 dY: -0.12,
0.12 dZ: 0.02,
0.02 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: DCPath
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
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Example – Return Path
Save Project
To save the project:
1. In an Ansoft HFSS window, select the menu item File > Save
Analyze
Model Validation
To validate the model:
1. Select the menu item HFSS > Validation Check
2. Click the Close button
Analyze
To start the solution process:
1. Select the menu item HFSS > Analyze All
To Open All Existing Report
To open all reports:
1. Select the menu item HFSS > Results > Open All Reports
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Example – Return Path
Return Path – Add a RF Return Path
We will continue our investigation by adding an RF return path between the two
ground planes. The RF return path will be the path of least inductance.
RF Return Path
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Example – Return Path
Copy the Design
To copy the entire design:
1. Using the project manager,
1. Right-click on HFSSModel1,
HFSSModel1 and choose Copy
2. Using the project manager,
1. Right-click on hfss_returnpath,
hfss_returnpath and choose Paste
Open the 3D Model Editor
To open the 3D Model Editor:
1. Using the project manager,
1. Right-click on HFSSModel3 and choose 3D Model Editor
Set Default Material
To set the default material:
1. Using the 3D Modeler Materials toolbar, choose pec
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Example – Return Path
Create RF Path
To create the RF path:
1. Select the menu item Draw > Line
2. Using the coordinate entry fields, enter the vertex point:
X: -1.0,
1.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the radial point:
X: -0.972,
0.972 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
4. Using the coordinate entry fields, enter the sweep arc length:
X: -0.972,
0.972 Y: 0.0,
0.0 Z: 1.072,
1.072 Press the Enter key
5. Using the coordinate entry fields, enter the sweep arc length:
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 1.072,
1.072 Press the Enter key
6. Using the mouse, right-click and select Done
7. Click the OK button when the Properties dialog appears
To set the grid plane:
1. Select the menu item 3D Modeler > Grid Plane > YZ
To create the profile:
1. Select the menu item Draw > Rectangle
2. Using the coordinate entry fields, enter the box position
X: -1.0,
1.0 Y: -0.06,
0.06 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the base
rectangle:
dX: 0.0,
0.02,
0.0 dY: 0.12,
0.12 dZ: -0.02
0.02 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: RFPath
3. Click the OK button
To Sweep the profile:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Polyline2, RFPath
2. Click the OK button
3. Select the menu item Draw > Sweep > Along Path
4. Click the OK button when the Sweep along path dialog appears
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Example – Return Path
Mirror Conductor
To duplicate the existing objects:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: RFPath
2. Click the OK button
3. Select the menu item, Edit > Duplicate > Mirror.
1. Input the anchor point of the mirror plane:
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter key
2. Input the target point of the vector normal to the mirror plane:
dX: 1.0,
1.0 dY: 0.0,
0.0 dZ: 0.0,
0.0 Press the Enter key
Group Conductors
To group the conductors:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: RFPath,
RFPath, RFPath_1
2. Click the OK button
3. Select the menu item, 3D Modeler > Boolean > Unite
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Example – Return Path
Save Project
To save the project:
1. In an Ansoft HFSS window, select the menu item File > Save
Analyze
Model Validation
To validate the model:
1. Select the menu item HFSS > Validation Check
2. Click the Close button
Analyze
To start the solution process:
1. Select the menu item HFSS > Analyze
To Open All Existing Report
To open all reports:
1. Select the menu item HFSS > Results > Open All Reports
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8.4
Example – Return Path
Exiting HFSS
To Exit HFSS:
1. Select the menu item File > Exit
1. If prompted Save the changes
Ansoft High Frequency Structure Simulator v10 User’s Guide
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Chapter 9.0
Chapter 9.0 – EMC/EMI Examples
9.1 – Heat Sink
9.2 - Enclosure
Ansoft High Frequency Structure Simulator v10 User’s Guide
9.1
Example – Heat Sink
Heat Sink
This example is intended to show you how to create, simulate, and analyze a
heat sink using the Ansoft HFSS Design Environment.
With higher power and microwave clock speed, containing emissions from heat
sinks for microelectronics is rapidly becoming a necessity. We will investigate
the performance of a single grounding configuration. The following illustrations
detail the passive device you will be creating:
Heat Sink
Ground Pins
1
Top View
Ground Plane
Heat Sink/Ground/Ground Pins = Perfect Conductor
2
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9.1
Example – Heat Sink
Ansoft HFSS Design Environment
The following features of the Ansoft HFSS Design Environment are used to
create this passive device model:
3D Solid Modeling
Primitives: Box, Rectangle
Boundaries/Excitations
Boundaries: Perfect H, Perfect E
Results
Eigenmode Data
Fields: E- & HH-Field
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9.1
Example – Heat Sink
Design Review
Before we jump into setting up this device lets review the design.
Port Size/Type= ???
Free Space= ??
Port Size/Type
The goal of this simulation is to determine the effectiveness of various
grounding conditions at reducing the radiated emissions from a heat sink.
There are two methods we could use to analyze this problem:
Method 1: Define a port which will excite the structure and
measure the radiated emissions some distance from the model to
determine the resonant frequencies. From the radiated
emissions, the low frequency performance can be determined.
This can be very computer intensive and depending on the
location of the excitation, modes can be missed.
Method 2:
2 Use the Eigenmode solver to determine the natural
resonances of the heat sink. This will not give us the radiated
emissions, but it will quickly tell us which configuration reduces
the low frequency emissions.
Let’s try Case 2. The Eigenmode solver does not use ports so we only
have to define the geometry and the boundary conditions.
Free Space
The Eigenmode Solver does not support radiation boundaries.
Therefore, we will apply a perfect H boundary to the outside of the model
to simulate free space.
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9.1
Example – Heat Sink
Getting Started
Launching Ansoft HFSS
1.
To access Ansoft HFSS, click the Microsoft Start button, select Programs,
Programs and select
the Ansoft HFSS 10 program group. Click HFSS 10.
10
Setting Tool Options
To set the tool options:
Note: In order to follow the steps outlined in this example, verify that the
following tool options are set :
1. Select the menu item Tools > Options > HFSS Options
2. HFSS Options Window:
1. Click the General tab
Use Wizards for data entry when creating new boundaries:: Checked
Duplicate boundaries with geometry:: Checked
2. Click the OK button
3. Select the menu item Tools > Options > 3D Modeler Options.
Options
4. 3D Modeler Options Window:
1. Click the Operation tab
Automatically cover closed polylines:: Checked
2. Click the Drawing tab
Edit property of new primitives:: Checked
3. Click the OK button
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9.1
Example – Heat Sink
Opening a New Project
To open a new project:
1. In an Ansoft HFSS window, click the On the Standard toolbar, or
select the menu item File > New.
2. From the Project menu, select Insert HFSS Design.
Set Solution Type
To set the solution type:
1. Select the menu item HFSS > Solution Type
2. Solution Type Window:
1. Choose Eigenmode
2. Click the OK button
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9.1
Example – Heat Sink
Creating the 3D Model
Set Model Units
To set the units:
1. Select the menu item 3D Modeler > Units
2. Set Model Units:
1. Select Units: mm
2. Click the OK button
Set Default Material
To set the default material:
Using the 3D Modeler Materials toolbar, choose vacuum
Create an Air box
Create Air box
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: -80.0,
80.0 Y:: -60.0,
60.0 Z:: 0.0, Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the base
rectangle:
dX:: 160.0,
160.0 dY:: 120.0,
120.0 dZ:: 44.1, Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Air
To set the Wireframe view:
1. Select the Attribute tab from the Properties window.
2. Display Wireframe: Checked
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View
or press the CTRL+D key
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9.1
Example – Heat Sink
Assign a Perfect H boundary to Air
To select the Air:
1. Select the menu item Edit > Select All
To assign the Perfect H boundary
1. Select the menu item HFSS > Boundaries > Assign > Perfect H
2. Perfect H Boundary window
1. Name: Open
2. Click the OK button
Set Default Material
To set the default material:
1. Using the 3D Modeler Materials toolbar, choose Select
2. Select Definition Window:
1. Type pec in the Search by Name field
2. Click the OK button
Create the Heat Sink
Create Heat Sink
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: -44.45,
44.45 Y:: -31.75,
31.75 Z:: 6.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the base
rectangle:
dX:: 88.9,
88.9 dY:: 63.5,
63.5 dZ:: 38.1 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Sink
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
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9.1
Example – Heat Sink
Create Offset Coordinate System
Create CS
1. Select the menu item 3D Modeler > Coordinate System > Create >
Relative CS > Offset
2.
Using the coordinate entry fields, enter the origin
X: -44.45,
44.45 Y: 0.0,
0.0 Z: 6.0 Press the Enter key
Create a Ground Pin 1
Create Ground Pin 1
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: 0.0,
0.0 Y:: -3.0,
3.0 Z:: 0.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the base
rectangle:
dX:: 6.0,
6.0 dY:: 6.0,
6.0 dZ:: -6.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Ground_Pin
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
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Example – Heat Sink
Create Ground Pin 2
To select the object Ground_Pin:
Ground_Pin:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Ground_Pin
2. Click the OK button
To create Ground Pin 2:
1. Select the menu item, Edit > Duplicate > Along Line.
1. First Point: X:: 6.0, Y:: 0.0, Z:: 0.0 Press the Enter key
2. Second Point: dX:: 82.9,
82.9 dY:: 0.0,
0.0 dZ:: 0.0 Press the Enter key
3. Total Number: 2
4. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Set Working Coordinate System
To set the working coordinate system:
1. Select the menu item 3D Modeler > Coordinate System > Set Working CS
2. Select Coordinate System Window,
1. From the list, select the CS: Global
2. Click the Select button
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Example – Heat Sink
Create Ground
To create ground:
1. Select the menu item Draw > Rectangle
2. Using the coordinate entry fields, enter the box position
X: -80.0,
80.0 Y:: -60.0,
60.0 Z:: 0.0, Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the base
rectangle:
dX:: 160.0,
160.0 dY:: 120.0,
120.0 dZ:: 0.0, Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Ground
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Assign a Perfect E boundary to the Ground
To select the ground:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Ground
2. Click the OK button
To assign the Perfect E boundary
1. Select the menu item HFSS > Boundaries > Assign > Perfect E
2. Perfect E Boundary window
1. Name: PerfE_Ground
2. Click the OK button
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9.1
Example – Heat Sink
Mesh Operations
To select an object:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Ground
2. Click the OK button
To assign a mesh operation:
1. Select the menu item, HFSS > Mesh Operations > Assign > On Selection >
Length Based
2.
Element Length Based Refinement Dialog.
1. Name: Ground
2. Restrict Length of Elements: Unchecked
3.
4.
5.
Restrict Number of Elements: Checked
Maximum Number of Elements: 1000
Click the OK button
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9.1
Example – Heat Sink
Analysis Setup
Creating an Analysis Setup
To create an analysis setup:
1. Select the menu item HFSS > Analysis Setup > Add Solution Setup
2. Solution Setup Window:
1. Click the General tab::
Minimum Frequency:: 0.1 GHz
Number of Modes:: 2
Maximum Number of Passes: 10
Maximum Delta Frequency per Pass: 1%
2. Click the OK button
Save Project
To save the project:
1. In an Ansoft HFSS window, select the menu item File > Save As.
2. From the Save As window, type the Filename: hfss_heat_sink
3. Click the Save button
Analyze
Model Validation
To validate the model:
1. Select the menu item HFSS > Validation Check
2. Click the Close button
Note: To view any errors or warning messages, use the Message
Manager.
Analyze
To start the solution process:
1. Select the menu item HFSS > Analyze All
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9.1
Example – Heat Sink
Solution Data
To view the Solution Data:
1. Select the menu item HFSS > Results > Solution Data
To view the Profile:
1. Click the Profile Tab.
To view the Convergence:
1. Click the Convergence Tab
Note: The default view is for convergence is Table.
Table Select
the Plot radio button to view a graphical representations of
the convergence data.
To view the Eigenmode Data:
1. Click the Eigenmode Data Tab
Note: To view a real-time update of the Eigenmode Data, set
the Simulation to Setup1, Last Adaptive
2. Click the Close button
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9.1
Example – Heat Sink
Field Overlays
Create Field Overlay
To create a field plot:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Ground
2. Click the OK button
3. Select the menu item HFSS > Fields > Fields > E > Mag_E
4. Create Field Plot Window
1. Solution: Setup1 : LastAdaptive
2. Quantity: Mag_E
3. In Volume: All
4. Click the Done button
Mode 1: EE-Field
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9.1
Example – Heat Sink
Edit Sources
To Excite Mode 2:
1. Select the menu item HFSS > Fields > Edit Sources
2. Edit Sources window
1. Source: EigenMode_1
1. Scaling Factor: 0
2. Offset Phase: 0
2. Source: EigenMode_2
1. Scaling Factor: 1
2. Offset Phase: 0
3. Click the OK button
Mode 2: EE-Field
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9.1
Example – Heat Sink
Create Field Overlay
To create a field plot:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Ground
2. Click the OK button
3. Select the menu item HFSS > Fields > Fields > H > Mag_H
4. Create Field Plot Window
1. Solution: Setup1 : LastAdaptive
2. Quantity: Mag_H
3. In Volume: All
4. Click the Done button
Edit Sources
To Excite Mode 1:
1. Select the menu item HFSS > Fields > Edit Sources
2. Edit Sources window
1. Source: EigenMode_1
1. Scaling Factor: 1
2. Offset Phase:: 90
2. Source: EigenMode_2
1. Scaling Factor: 0
2. Offset Phase: 0
3. Click the OK button
Mode 1: HH-Field
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9.1
Example – Heat Sink
Edit Sources
To Excite Mode 2:
1. Select the menu item HFSS > Fields > Edit Sources
2. Edit Sources window
1. Source: EigenMode_1
1. Scaling Factor: 0
2. Offset Phase:: 0
2. Source: EigenMode_2
1. Scaling Factor: 1
2. Offset Phase: 90
3. Click the OK button
Mode 2: HH-Field
Exiting HFSS
To Exit HFSS:
1. Select the menu item File > Exit
1. If prompted Save the changes
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9.2
Example – Enclosure
Shielded Enclosure
This example is intended to show you how to create, simulate, and analyze a
shielded enclosure using the Ansoft HFSS Design Environment.
Shielding enclosures for high-speed digital designs can be compromised by
slots and apertures. Therefore an understanding of the energy coupling
mechanisms is essential.
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9.2
Example – Enclosure
Ansoft HFSS Design Environment
The following features of the Ansoft HFSS Design Environment are used to
create this passive device model:
3D Solid Modeling
Primitives: Box, Rectangle, Cylinder
Boolean: Unite, Subtract
Boundaries/Excitations
Boundaries: Lumped RLC, Radiation
Results
Reports: S-Parameters
Fields: E-Field
Ansoft High Frequency Structure Simulator v10 User’s Guide
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9.2
Example – Enclosure
References
1.
EMI from Shielding Enclosures—FDTD Modeling and Measurements, Min Li,
Electromagnetic Compatibility Laboratory, University of Missouri-Rolla March
1999
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9.2
Example – Enclosure
Getting Started
Launching Ansoft HFSS
1.
To access Ansoft HFSS, click the Microsoft Start button, select Programs,
Programs and select
the Ansoft HFSS 10 program group. Click HFSS 10.
10
Setting Tool Options
To set the tool options:
Note: In order to follow the steps outlined in this example, verify that the
following tool options are set :
1. Select the menu item Tools > Options > HFSS Options
2. HFSS Options Window:
1. Click the General tab
Use Wizards for data entry when creating new boundaries:: Checked
Duplicate boundaries with geometry:: Checked
2. Click the OK button
3. Select the menu item Tools > Options > 3D Modeler Options.
Options
4. 3D Modeler Options Window:
1. Click the Operation tab
Automatically cover closed polylines:: Checked
2. Click the Drawing tab
Edit property of new primitives:: Checked
3. Click the OK button
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9.2
Example – Enclosure
Opening a New Project
To open a new project:
1. In an Ansoft HFSS window, click the On the Standard toolbar, or
select the menu item File > New.
2. From the Project menu, select Insert HFSS Design.
Set Solution Type
To set the solution type:
1. Select the menu item HFSS > Solution Type
2. Solution Type Window:
1. Choose Driven Terminal
2. Click the OK button
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9.2
Example – Enclosure
Creating the 3D Model
Set Model Units
To set the units:
1. Select the menu item 3D Modeler > Units
2. Set Model Units:
1. Select Units: cm
2. Click the OK button
Set Default Material
To set the default material:
Using the 3D Modeler Materials toolbar, choose vacuum
Create the Air Inside case
Create Air Inside Case
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: 0.0,
0.0 Y:: 0.0,
0.0 Z:: 0.0, Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the base
rectangle:
dX:: 22.0,
22.0 dY:: 14.0,
14.0 dZ:: 30.0, Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Air_Inside
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Or press the CTRL+D key
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9.2
Example – Enclosure
Create the Slot
Create Slot
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: 0.0,
0.0 Y:: 0.2,
0.2 Z:: 9.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the base
rectangle:
dX:: -0.05,
0.05 dY:: 0.1,
0.1 dZ:: 12.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Slot
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Create an Air box
Create an Air box
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: -4.05,
4.05 Y:: -4.05,
4.05 Z:: -4.05, Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the base
rectangle:
dX:: 28.1,
28.1 dY:: 20.1,
20.1 dZ:: 38.1, Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Air
3. Display Wireframe: Checked
4. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Create Offset Coordinate System
Create CS
1. Select the menu item 3D Modeler > Coordinate System > Create > Relative
CS > Offset
2.
Using the coordinate entry fields, enter the origin
X: 17.0,
17.0 Y: 14.0,
14.0 Z: 15.0 Press the Enter key
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9.2
Example – Enclosure
Create Coax Dielectric
To create the coax dielectric:
1. From the Drawing Plane toolbar, change the active plane to XZ.
XZ
2. Select the menu item Draw > Cylinder
3. Using the coordinate entry fields, enter the center position
X:: 0.0,
0.0 Y:: 0.0,
0.0 Z:: 0.0, Press the Enter key
4. Using the coordinate entry fields, enter the radius of the cylinder
dX:: 0.16,
0.16 dY:: 0.0,
0.0 dZ:: 0.0
0 0, Press the Enter key
5. Using the coordinate entry fields, enter the height of the cylinder
dX:: 0.0,
0.0 dY:: 2.05,
2.05 dZ:: 0.0,
0.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Coax_Diel
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View
Group Objects
To group the objects:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Air_Inside,
Air_Inside, Coax_Diel,
Coax_Diel, Slot
2. Click the OK button.
3. Select the menu item, 3D Modeler > Boolean > Unite
To fit the view:
1. Select the menu item View > Fit All > Active View.
Set Default Material
To set the default material:
1. Using the 3D Modeler Materials toolbar, choose Select
2. Select Definition Window:
1. Type pec in the Search by Name field
2. Click the OK button
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Example – Enclosure
Create Coax Shield
To create the coax shield:
1. From the Drawing Plane toolbar, change the active plane to XZ.
XZ
2. Select the menu item Draw > Cylinder
3. Using the coordinate entry fields, enter the center position
X:: 0.0,
0.0 Y:: 0.0,
0.0 Z:: 0.0, Press the Enter key
4. Using the coordinate entry fields, enter the radius of the cylinder
dX:: 0.21,
0.21 dY:: 0.0,
0.0 dZ:: 0.0
0 0, Press the Enter key
5. Using the coordinate entry fields, enter the height of the cylinder
dX:: 0.0,
0.0 dY:: 2.05,
2.05 dZ:: 0.0,
0.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Coax_Shield
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View
Create Coax Pin
To create the coax pin:
1. From the Drawing Plane toolbar, change the active plane to XZ.
XZ
2. Select the menu item Draw > Cylinder
3. Using the coordinate entry fields, enter the center position
X:: 0.0,
0.0 Y:: 2.05,
2.05 Z:: 0.0, Press the Enter key
4. Using the coordinate entry fields, enter the radius of the cylinder
dX:: 0.08,
0.08 dY:: 0.0,
0.0 dZ:: 0.0
0 0, Press the Enter key
5. Using the coordinate entry fields, enter the height of the cylinder
dX:: 0.0,
0.0 dY:: -15.89,
15.89 dZ:: 0.0,
0.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Coax_Pin
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View
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Example – Enclosure
Create the Wave port
To create a circle that represents the port:
1. From the Drawing Plane toolbar, change the active plane to XZ.
XZ
2. Select the menu item Draw > Circle
3. Using the coordinate entry fields, enter the center position
X:: 0.0,
0.0 Y:: 2.05,
2.05 Z:: 0.0, Press the Enter key
4. Using the coordinate entry fields, enter the radius of the circle:
dX:: 0.16,
0.16 dY:: 0.0,
0.0 dZ:: 0.0
0 0, Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: p1
3. Click the OK button
To select the object p1:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: p1
2. Click the OK button
To assign wave port excitation
1. Select the menu item HFSS > Excitations > Assign > Wave Port
2. Wave Port : General
1. Name: p1,
p1
2. Click the Next button
3. Wave Port : Terminals
1. Number of Terminals: 1,
2. For T1,
T1 click the Undefined column and select New Line
3. Using the coordinate entry fields, enter the vector position
X: 0.16,
0.16 Y: 2.05,
2.05 Z: 0.0, Press the Enter key
4. Using the coordinate entry fields, enter the vertex
dX:: -0.08, dY:
dY: 0.0,
0.0 dZ: 0.0, Press the Enter key
5. Click the Next button
4. Wave Port : Differential Pairs
1. Click the Next button
5. Wave Port : Post Processing
1. Reference Impedance: 50
6. Click the Finish button
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Example – Enclosure
Create Offset Coordinate System
Create CS
1. Select the menu item 3D Modeler > Coordinate System > Create >
Relative CS > Offset
2.
Using the coordinate entry fields, enter the origin
X: 0.0,
0.0 Y: -13.84,
13.84 Z: 0.0 Press the Enter key
Create Resistor
To create the Resistor:
1. From the Drawing Plane toolbar, change the active plane to XY.
XY
2. Select the menu item Draw > Rectangle
3. Using the coordinate entry fields, enter the box position
X: -0.08,
0.08 Y:: 0.0,
0.0 Z:: 0.0, Press the Enter key
4. Using the coordinate entry fields, enter the opposite corner of the base
rectangle:
dX:: 0.16,
0.16 dY:: -0.16,
0.16 dZ:: 0.0, Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Resistor
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
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Example – Enclosure
Assign a Lumped RLC boundary to the Resistor
To select the ground:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Resistor
2. Click the OK button
To assign the Perfect E boundary
1. Select the menu item HFSS > Boundaries > Assign > Lumped RLC
2. Lumped RLC Boundary window
1. Name: Resistor
2.
3.
4.
Resistance: 47 ohm
Current Flow Line:: New Line
1. Point 1: X:: 0.0,
0.0 Y: 0.0,
0.0 Z: 0.0,
0.0 Press the Enter Key
2. Point 2: dX:: 0.0,
0.0 dY:: -0.16,
0.16 dZ: 0.0,
0.0 Press the Enter Key
Click the OK button
Set Working Coordinate System
To set the working coordinate system:
1. Select the menu item 3D Modeler > Coordinate System > Set Working CS
2. Select Coordinate System Window,
1. From the list, select the CS: Global
2. Click the Select button
Ansoft High Frequency Structure Simulator v10 User’s Guide
9.2-12
9.2
Example – Enclosure
Create the Case
Create Case
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: -0.05,
0.05 Y:: -0.05,
0.05 Z:: -0.05, Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the base
rectangle:
dX:: 22.1,
22.1 dY:: 14.1,
14.1 dZ:: 30.1, Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Case
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Group Objects
To group the objects:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Case, Coax_Shield
2. Click the OK button
3. Select the menu item, 3D Modeler > Boolean > Unite
To fit the view:
1. Select the menu item View > Fit All > Active View.
Ansoft High Frequency Structure Simulator v10 User’s Guide
9.2-13
9.2
Example – Enclosure
Complete the Case
To select the objects:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Case, Air_Inside
2. Click the OK button
To complete the case:
1. Select the menu item 3D Modeler > Boolean > Subtract
2. Subtract Window
Blank Parts: Case
Tool Parts: Air_Inside
Clone tool objects before subtract: Unchecked
Click the OK button
Create Radiation Boundary
To create a radiation boundary
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Air
2. Click the OK button
3. Select the menu item HFSS > Boundaries > Assign > Radiation
4. Radiation Boundary window
1. Name: Rad1
2. Click the OK button
Ansoft High Frequency Structure Simulator v10 User’s Guide
9.2-14
9.2
Example – Enclosure
Analysis Setup
Creating an Analysis Setup
To create an analysis setup:
1. Select the menu item HFSS > Analysis Setup > Add Solution Setup
2. Solution Setup Window:
1. Click the General tab::
Solution Frequency:: 1.1 GHz
Maximum Number of Passes: 10
Maximum Delta S: 0.02
2. Click the OK button
Adding a Frequency Sweep
To add a frequency sweep:
1. Select the menu item HFSS > Analysis Setup > Add Sweep
1. Select Solution Setup: Setup1
2. Click the OK button
2. Edit Sweep Window:
1. Sweep Type:: Fast
2. Frequency Setup Type:: Linear Count
Start: 0.6 GHz
Stop:: 1.6 GHz
Count:: 201
Save Fields: Checked
3. Click the OK button
Ansoft High Frequency Structure Simulator v10 User’s Guide
9.2-15
9.2
Example – Enclosure
Save Project
To save the project:
1. In an Ansoft HFSS window, select the menu item File > Save As.
2. From the Save As window, type the Filename: hfss_enclosure
3. Click the Save button
Analyze
Model Validation
To validate the model:
1. Select the menu item HFSS > Validation Check
2. Click the Close button
Note: To view any errors or warning messages, use the Message
Manager.
Analyze
To start the solution process:
1. Select the menu item HFSS > Analyze All
Ansoft High Frequency Structure Simulator v10 User’s Guide
9.2-16
9.2
Example – Enclosure
Solution Data
To view the Solution Data:
1. Select the menu item HFSS > Results > Solution Data
To view the Profile:
1. Click the Profile Tab.
To view the Convergence:
1. Click the Convergence Tab
Note: The default view is for convergence is Table.
Table Select
the Plot radio button to view a graphical representations of
the convergence data.
To view the Matrix Data:
1. Click the Matrix Data Tab
Note: To view a real-time update of the Matrix Data, set the
Simulation to Setup1, Last Adaptive
2. Click the Close button
Ansoft High Frequency Structure Simulator v10 User’s Guide
9.2-17
9.2
Example – Enclosure
Create Reports
Create Terminal SS-Parameter Plot - Magnitude
To create a report:
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Terminal S Parameters
2. Display Type: Rectangular
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: Sweep1
2. Domain: Sweep
3. Click the Y tab
1. Category: Terminal S Parameter
2. Quantity: St(p1,p1),
3. Function: dB
4. Click the Add Trace button
4. Click the Done button
Ansoft High Frequency Structure Simulator v10 User’s Guide
9.2-18
9.2
Example – Enclosure
Create Reports (Continued)
Custom Equations – Output Variables
1.
2.
Select the menu item HFSS > Results > Create Report
Create Report Window::
1. Report Type: Terminal S Parameters
Vs2
2
2. Display Type: Rectangular
P
=
1
−
S
11
3. Click the OK button
8Z o
Traces Window::
Power Delivered
1. Click the Output Variables button
Vs – Source Voltage (1mV)
2. Output Variables dialog:
1. Name: Pdelivered_nW
Zo - 50Ω
2. Expression:
(1mv)^2/8*50 = 2.5e-9
Type: 2.5*(12.5*(1Category: Terminal S Parameters
Quantity: St(p1,p1)
Function: mag
Click the Insert Quantity into Expression button
Type: ^2)
3. Click the Add button
4. Click the Done button
3. Solution: Setup1: Sweep1
4. Domain: Sweep
5. Click the Y tab
1. Category: Output Variables
2. Quantity: Pdelivered_nW
3. Function: <none>
4. Click the Add Trace button
6. Click the Done button
(
3.
Ansoft High Frequency Structure Simulator v10 User’s Guide
)
9.2-19
9.2
Example – Enclosure
Ansoft High Frequency Structure Simulator v10 User’s Guide
9.2-20
9.2
Example – Enclosure
Field Overlays
To create a field plot:
1. Select an object to overlay fields
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Air
2. Click the OK button
Note:
Note You can also select the object from the Model Tree
2. Select the menu item HFSS > Fields > Fields > E > Mag_E
3. Create Field Plot Window
1. Solution: Setup1 : Sweep1
2. Freq: 0.89 GHz
3. Quantity: Mag_E
4. In Volume: All
5. Click the Done button
To modify the attributes of a field plot:
1. Select the menu item HFSS > Fields > Modify Plot Attributes
2. Select Plot Folder Window:
1. Select: E Field
2. Click the OK button
3. E-Field Window:
1. Click the Scale tab
1. Select Use Limits
2. Min: 5
3. Max: 600
4. Scale: Log
2. Click the Plot tab
1. IsoValType: IsoValSurface
2. Click the Apply button.
4. Click the Close button
Ansoft High Frequency Structure Simulator v10 User’s Guide
9.2-21
9.2
Example – Enclosure
Field Overlays
To modify the Frequency of a field plot:
1. Select the menu item HFSS > Fields > Modify Plot
2. Select Plot Folder Window:
1. Select: E Field
2. Click the OK button
3. Create Field Plot Window
1. Solution: Setup1 : Sweep1
2. Freq: 1.08 GHz
1.08 GHz
Ansoft High Frequency Structure Simulator v10 User’s Guide
1.51 GHz
9.2-22
Chapter 10.0
Chapter 10.0 – On-Chip Passives Examples
10.1 – Spiral Inductor
Ansoft High Frequency Structure Simulator v10 User’s Guide
10.1
Example – Silicon Spiral Inductor
The Silicon Spiral Inductor
This example is intended to show you how to create, simulate, and analyze a 2.5
turn spiral inductor using the Ansoft HFSS Design Environment.
Nominal Design:
Spiral: 2.5T, W=15um, S=1.5um, Rad=60um
M6, 2um, σ= 2.8e7 S/m
Underpass: M5, 0.5um, σ= 2.8e7 S/m
Passivation
Stackup:
Passivation:
Passivation: 0.7um
Oxide
M6
M5
εr = 7.9
Oxide: 9.8um
εr = 4.0
Substrate: 300um
εr = 11.9, σ= 10 S/m
Ansoft High Frequency Structure Simulator v10 User’s Guide
Substrate
10.1-1
10.1
Example – Silicon Spiral Inductor
Getting Started
Launching Ansoft HFSS
1.
To access Ansoft HFSS, click the Microsoft Start button, select Programs,
Programs and
select the Ansoft > HFSS 10 program group. Click HFSS 10.
10
Setting Tool Options
To set the tool options:
Note: In order to follow the steps outlined in this example, verify that the
following tool options are set :
1. Select the menu item Tools > Options > HFSS Options
2. HFSS Options Window:
1. Click the General tab
Use Wizards for data entry when creating new boundaries:: Checked
Duplicate boundaries with geometry:: Checked
2. Click the OK button
3. Select the menu item Tools > Options > 3D Modeler Options.
Options
4. 3D Modeler Options Window:
1. Click the Operation tab
Automatically cover closed polylines:: Checked
2. Click the Drawing tab
Edit property of new primitives:: Checked
3. Click the OK button
Ansoft High Frequency Structure Simulator v10 User’s Guide
10.1-2
10.1
Example – Silicon Spiral Inductor
Opening a New Project
To open a new project:
In an Ansoft HFSS window, click the On the Standard toolbar, or select
the menu item File > New.
From the Project menu, select Insert HFSS Design.
Set Solution Type
To set the solution type:
Select the menu item HFSS > Solution Type
Solution Type Window:
Choose Driven Terminal
Click the OK button
Ansoft High Frequency Structure Simulator v10 User’s Guide
10.1-3
10.1
Example – Silicon Spiral Inductor
Creating the 3D Model
Set Model Units
To set the units:
1. Select the menu item 3D Modeler > Units
2. Set Model Units:
1. Select Units: um
2. Click the OK button
Set Default Material
To set the default material:
1. Using the 3D Modeler Materials toolbar, choose Select
2. Select Definition Window:
1. Click the Add Material button
2. View/Edit Material Window:
1. For the Material Name type: My_Sub
2. For the Value of Relative Permittivity type: 11.9
3. For the Value of Bulk Conductivity type: 10
4. Click the OK button
3. Click the OK button
Ansoft High Frequency Structure Simulator v10 User’s Guide
10.1-4
10.1
Example – Silicon Spiral Inductor
Create Substrate
To create the substrate:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: -270.0,
270.0 Y: -270.0,
270.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the box:
dX: 540.0,
540.0 dY: 540.0,
540.0 dZ: 300.0,
300.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Sub
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Set Default Material
To set the default material:
1. Using the 3D Modeler Materials toolbar, choose Select
2. Select Definition Window:
1. Click the Add Material button
2. View/Edit Material Window:
1. For the Material Name type: My_Oxide
2. For the Value of Relative Permittivity type: 4.0
3. Click the OK button
3. Click the OK button
Ansoft High Frequency Structure Simulator v10 User’s Guide
10.1-5
10.1
Example – Silicon Spiral Inductor
Create Oxide
To create substrate:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: -270.0,
270.0 Y: -270.0,
270.0 Z: 300.0,
300.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the box:
dX: 540.0,
540.0 dY: 540.0,
540.0 dZ: 9.8,
9.8 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Oxide
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View
Set Default Material
To set the default material:
1. Using the 3D Modeler Materials toolbar, choose Select
2. Select Definition Window:
1. Click the Add Material button
2. View/Edit Material Window:
1. For the Material Name type: My_Pass
2. For the Value of Relative Permittivity type: 7.9
3. Click the OK button
3. Click the OK button
Ansoft High Frequency Structure Simulator v10 User’s Guide
10.1-6
10.1
Example – Silicon Spiral Inductor
Create Passivation
To create substrate:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: -270.0,
270.0 Y: -270.0,
270.0 Z: 309.8,
309.8 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the box:
dX: 540.0,
540.0 dY: 540.0,
540.0 dZ: 0.7,
0.7 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Pass
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View
Set Default Material
To set the default material:
1. Using the 3D Modeler Materials toolbar, choose vacuum
Create Air
To create air:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: -270.0,
270.0 Y: -270.0,
270.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the box:
dX: 540.0,
540.0 dY: 540.0,
540.0 dZ: 600.0,
600.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Air
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View
Ansoft High Frequency Structure Simulator v10 User’s Guide
10.1-7
10.1
Example – Silicon Spiral Inductor
Create Radiation Boundary
To select the object Air:
Air
Select the menu item Edit > Select > By Name
Select Object Dialog,
Select the objects named: Air
Click the OK button
To create a radiation boundary
Select the menu item HFSS > Boundaries > Assign > Radiation
Radiation Boundary Window
Name: Rad1
Click the OK button
Create Ground
To create ground:
Select the menu item Draw > Rectangle
Using the coordinate entry fields, enter the box position
X: -270.0,
270.0 Y: -270.0,
270.0 Z: 0.0,
0.0 Press the Enter key
Using the coordinate entry fields, enter the opposite corner of the base
rectangle:
dX: 540.0,
540.0 dY: 540.0,
540.0 dZ: 0.0,
0.0 Press the Enter key
To set the name:
Select the Attribute tab from the Properties window.
For the Value of Name type: Ground
Click the OK button
To fit the view:
Select the menu item View > Fit All > Active View.
Ansoft High Frequency Structure Simulator v10 User’s Guide
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10.1
Example – Silicon Spiral Inductor
Assign a Perfect E boundary to the Ground
To select the ground:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Ground
2. Click the OK button
To assign the Perfect E boundary
1. Select the menu item HFSS > Boundaries > Assign > Perfect E
2. Perfect E Boundary window
1. Name: PerfE_Ground
2. Click the OK button
Hide Dielectrics
To hide the dielectrics:
1. Select the menu item Edit > Select All Visible
2. Select the menu item View > Hide Selection > All Views
Set Default Material
To set the default material:
1. Using the 3D Modeler Materials toolbar, choose Select
2. Select Definition Window:
1. Click the Add Material button
2. View/Edit Material Window:
1. For the Material Name type: My_Met
2. For the Value of Bulk Conductivity type: 2.8e7
3. Click the OK button
3. Click the OK button
Create Offset Coordinate System
To create an offset Coordinate System:
1. Select the menu item 3D Modeler > Coordinate System > Create >
Relative CS > Offset
2.
Using the coordinate entry fields, enter the origin
X: 0.0,
0.0 Y: 0.0,
0.0 Z: 304.8,
304.8 Press the Enter key
Ansoft High Frequency Structure Simulator v10 User’s Guide
10.1-9
10.1
Example – Silicon Spiral Inductor
Create Spiral Path
To create the path:
1. Select the menu item Draw > Line
2. Using the coordinate entry fields, enter the vertex point:
X: -60.0,
60.0 Y: 7.5,
7.5 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the vertex point:
X: -60.0,
60.0 Y: -60.0,
60.0 Z: 0.0,
0.0 Press the Enter key
4. Using the coordinate entry fields, enter the vertex point:
X: 76.5,
76.5 Y: -60.0,
60.0 Z: 0.0,
0.0 Press the Enter key
5. Using the coordinate entry fields, enter the vertex point:
X: 76.5,
76.5 Y: 76.5,
76.5 Z: 0.0,
0.0 Press the Enter key
6. Using the coordinate entry fields, enter the vertex point:
X: -76.5
76.5,
76.5 Y: 76.5,
76.5 Z: 0.0,
0.0 Press the Enter key
7. Using the coordinate entry fields, enter the vertex point:
X: -76.5
76.5,
76.5,
76.5 Y: -76.5
76.5 Z: 0.0,
0.0 Press the Enter key
8. Using the coordinate entry fields, enter the vertex point:
X: 93.0,
76.5,
93.0 Y: -76.5
76.5 Z: 0.0,
0.0 Press the Enter key
9. Using the coordinate entry fields, enter the vertex point:
X: 93.0,
93.0 Y: 93.0,
93.0 Z: 0.0,
0.0 Press the Enter key
10. Using the coordinate entry fields, enter the vertex point:
X: -93.0
93.0,
93.0 Y: 93.0,
93.0 Z: 0.0,
0.0 Press the Enter key
11. Using the coordinate entry fields, enter the vertex point:
X: -93.0
93.0,
93.0,
93.0 Y: -93.0
93.0 Z: 0.0,
0.0 Press the Enter key
12. Using the coordinate entry fields, enter the vertex point:
X: 109.5,
93.0,
109.5 Y: -93.0
93.0 Z: 0.0,
0.0 Press the Enter key
13. Using the coordinate entry fields, enter the vertex point:
X: 109.5,
109.5 Y: 7.5,
7.5 Z: 0.0,
0.0 Press the Enter key
14. Using the coordinate entry fields, enter the vertex point:
X: 131.0,
131.0 Y: 7.5,
7.5 Z: 0.0,
0.0 Press the Enter key
15. Using the mouse, right-click and select Done
16. Click the OK button when the Properties dialog appears
Ansoft High Frequency Structure Simulator v10 User’s Guide
10.1-10
10.1
Example – Silicon Spiral Inductor
Create the Spiral
To set the grid plane:
1. Select the menu item 3D Modeler > Grid Plane > XZ
To create conductor profile:
1. Select the menu item Draw > Rectangle
2. Using the coordinate entry fields, enter the box position
X: -60.0,
60.0 Y: 7.5,
7.5 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the base
rectangle:
dX: -15.0,
15.0 dY: 0.0,
0.0 dZ: 2.0,
2.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Spiral
3. Click the OK button
To Sweep the profile:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Polyline1, Spiral
2. Click the OK button
Note:
Note You can also select the object from the Model Tree
1. Select the menu item Draw > Sweep > Along Path
2. Click the OK button when the Sweep along path dialog appears
To fit the view:
1. Select the menu item View > Fit All > Active View.
Ansoft High Frequency Structure Simulator v10 User’s Guide
10.1-11
10.1
Example – Silicon Spiral Inductor
Set Grid Plane
To set the grid plane:
1. Select the menu item 3D Modeler > Grid Plane > XY
Create Underpass
To create underpass:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: -60.0,
60.0 Y: 7.5,
7.5 Z: -0.8,
0.8 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the box:
dX: -75.0,
75.0 dY: -15.0,
15.0 dZ: -0.5,
0.5 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Underpass
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Ansoft High Frequency Structure Simulator v10 User’s Guide
10.1-12
10.1
Example – Silicon Spiral Inductor
Create Via1
To create via:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: -60.0,
60.0 Y: 7.5,
7.5 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the box:
dX: -15.0,
15.0 dY: -15.0,
15.0 dZ: -0.8,
0.8 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Via1
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Create Via2
To create via:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: -120.0,
120.0 Y: 7.5,
7.5 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the box:
dX: -15.0,
15.0 dY: -15.0,
15.0 dZ: -0.8,
0.8 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Via2
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Ansoft High Frequency Structure Simulator v10 User’s Guide
10.1-13
10.1
Example – Silicon Spiral Inductor
Create Feed
To create feed:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: -120.0,
120.0 Y: 7.5,
7.5 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the box:
dX: -22.0,
22.0 dY: -15.0,
15.0 dZ: 2.0,
2.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Feed
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Solve Inside Conductors
To solve inside:
1. Select the menu item Edit > Select All Visible
2. Select the menu item Edit > Properties
3. Properties Dialog Attribute Tab
1. Solve Inside: Checked
2. Click the OK button
Click the OK button for all warning messages (Solving inside a solid with high
conductivity may require a large mesh)
Seed Mesh Conductors set for Solve Inside
To solve inside:
1. Select the menu item Edit > Select All Visible
2. Select the menu item HFSS > Mesh Operations > Assign > Inside
Selection > Length Based
3.
Element Length Based Refinement Dialog
1. Restrict Length of Elements: Unchecked
2. Restrict Number of Elements: Checked
3. Maximum Number of Elements:: 5000
4. Click the OK button
Ansoft High Frequency Structure Simulator v10 User’s Guide
10.1-14
10.1
Example – Silicon Spiral Inductor
Set Default Material
To set the default material:
1. Using the 3D Modeler Materials toolbar, choose Select
2. Select Definition Window:
1. Type pec in the Search by Name field
2. Click the OK button
Create Ground Ring
To create outer ring:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: -225.0,
225.0 Y: -225.0,
225.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the box:
dX: 450.0,
450.0 dY: 450.0,
450.0 dZ: 2.0,
2.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Ring
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View
Create Inner Ring
To create inner ring:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: -210.0,
210.0 Y: -210.0,
210.0 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the box:
dX: 420.0,
420.0 dY: 420.0,
420.0 dZ: 2.0,
2.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Inner
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View
Ansoft High Frequency Structure Simulator v10 User’s Guide
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10.1
Example – Silicon Spiral Inductor
Complete the Ring
To select the objects Ring and Inner:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Ring, Inner
2. Click the OK button
To complete the ring:
1. Select the menu item 3D Modeler > Boolean > Subtract
2. Subtract Window
Blank Parts: Ring
Tool Parts: Inner
Click the OK button
Create Extension 1
To create extension:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: -157.0,
157.0 Y: 7.5,
7.5 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the box:
dX: -53.0,
53.0 dY: -15.0,
15.0 dZ: 2.0,
2.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Ring_Ext1
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View
Ansoft High Frequency Structure Simulator v10 User’s Guide
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10.1
Example – Silicon Spiral Inductor
Create Extension 2
To create extension:
1. Select the menu item Draw > Box
2. Using the coordinate entry fields, enter the box position
X: 146.0,
146.0 Y: 7.5,
7.5 Z: 0.0,
0.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the box:
dX: 64.0,
64.0 dY: -15.0,
15.0 dZ: 2.0,
2.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Ring_Ext2
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View
Group the Conductors
To group the conductors:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Ring, Ring_Ext1, Ring_Ext2
2. Click the OK button
3. Select the menu item, 3D Modeler > Boolean > Unite
To fit the view:
1. Select the menu item View > Fit All > Active View.
Ansoft High Frequency Structure Simulator v10 User’s Guide
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10.1
Example – Silicon Spiral Inductor
Create Source 1
To create source:
1. Select the menu item Draw > Rectangle
2. Using the coordinate entry fields, enter the box position
X: -142.0,
142.0 Y: 7.5,
7.5 Z: 1.0,
1.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the base
rectangle:
dX: -15.0,
15.0 dY: -15.0,
15.0 dZ: 0.0,
0.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Source1
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Assign Excitation
To select the object Source:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Source1
2. Click the OK button
Note:
Note You can also select the object from the Model Tree
To assign lumped port excitation
1. Select the menu item HFSS > Excitations > Assign > Lumped Port
2. Lumped Port : General
1. Name: p1,
p1
2. Resistance: 50
3. Reactance: 0
4. Click the Next button
3. Lumped Port : Terminals
1. Number of Terminals: 1,
2. For T1,
T1 click the Undefined column and select New Line
3. Using the coordinate entry fields, enter the vector position
X: -157.0,
157.0 Y: 0.0,
0.0 Z: 1.0,
1.0 Press the Enter key
4. Using the coordinate entry fields, enter the vertex
dX: 15.0,
15.0 dY: 0.0,
0.0 dZ: 0.0,
0.0 Press the Enter key
5. Click the Finish button
Ansoft High Frequency Structure Simulator v10 User’s Guide
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10.1
Example – Silicon Spiral Inductor
Create Source 2
To create source:
1. Select the menu item Draw > Rectangle
2. Using the coordinate entry fields, enter the box position
X: 131.0,
131.0 Y: 7.5,
7.5 Z: 1.0,
1.0 Press the Enter key
3. Using the coordinate entry fields, enter the opposite corner of the base
rectangle:
dX: 15.0,
15.0 dY: -15.0,
15.0 dZ: 0.0,
0.0 Press the Enter key
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Source2
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Assign Excitation
To select the object Source:
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Source2
2. Click the OK button
Note:
Note You can also select the object from the Model Tree
To assign lumped port excitation
1. Select the menu item HFSS > Excitations > Assign > Lumped Port
2. Lumped Port : General
1. Name: p2,
p2
2. Resistance: 50
3. Reactance: 0
4. Click the Next button
3. Lumped Port : Terminals
1. Number of Terminals: 1,
2. For T1,
T1 click the Undefined column and select New Line
3. Using the coordinate entry fields, enter the vector position
X: 146.0,
146.0 Y: 0.0,
0.0 Z: 1.0,
1.0 Press the Enter key
4. Using the coordinate entry fields, enter the vertex
dX: -15.0,
15.0 dY: 0.0,
0.0 dZ: 0.0,
0.0 Press the Enter key
5. Click the Finish button
Ansoft High Frequency Structure Simulator v10 User’s Guide
10.1-19
10.1
Example – Silicon Spiral Inductor
Show All
To show all object
1. Select the menu item View > Show All > All Views
Boundary Display
To verify the boundary setup:
1. Select the menu item HFSS > Boundary Display (Solver View)
2. From the Solver View of Boundaries, toggle the Visibility check box for the
boundaries you wish to display.
Note: The background (Perfect Conductor) is displayed as the outer
boundary.
Note: The Perfect Conductors are displayed as the smetal boundary.
Note: Select the menu item, View > Visibility to hide all of the
geometry objects. This makes it easier to see the boundary
3. Click the Close button when you are finished
Ansoft High Frequency Structure Simulator v10 User’s Guide
10.1-20
10.1
Example – Silicon Spiral Inductor
Analysis Setup
Creating an Analysis Setup
To create an analysis setup:
1. Select the menu item HFSS > Analysis Setup > Add Solution Setup
2. Solution Setup Window:
1. Click the General tab::
Solution Frequency:: 12.0GHz
Maximum Number of Passes: 20
Maximum Delta S: 0.02
2. Click the Options tab::
Do Lambda Refinement: Checked
Target:: 0.05
User Low-Order Solution Basis: Checked
3. Click the OK button
Adding a Frequency Sweep
To add a frequency sweep:
1. Select the menu item HFSS > Analysis Setup > Add Sweep
1. Select Solution Setup: Setup1
2. Click the OK button
2. Edit Sweep Window:
1. Sweep Type:: Interpolating
2. Click the Setup Interpolation Basis button
Max Solutions:: 20
Error Tolerance:: 0.5%
Click the OK button
3. Frequency Setup Type:: Linear Step
Start: 0.1GHz
Stop:: 20.0GHz
Step:: 0.1GHz
4. Click the OK button
Ansoft High Frequency Structure Simulator v10 User’s Guide
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10.1
Example – Silicon Spiral Inductor
Save Project
To save the project:
1. In an Ansoft HFSS window, select the menu item File > Save As.
2. From the Save As window, type the Filename: hfss_spiral_inductor
3. Click the Save button
Analyze
Model Validation
To validate the model:
1. Select the menu item HFSS > Validation Check
2. Click the Close button
Note: To view any errors or warning messages, use the Message
Manager.
Analyze
To start the solution process:
1. Select the menu item HFSS > Analyze All
Ansoft High Frequency Structure Simulator v10 User’s Guide
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10.1
Example – Silicon Spiral Inductor
Solution Data
To view the Solution Data:
1. Select the menu item HFSS > Results > Solution Data
To view the Profile:
1. Click the Profile Tab.
To view the Convergence:
1. Click the Convergence Tab
Note: The default view is for convergence is Table.
Table Select
the Plot radio button to view a graphical representations of
the convergence data.
To view the Matrix Data:
1. Click the Matrix Data Tab
Note: To view a real-time update of the Matrix Data, set the
Simulation to Setup1, Last Adaptive
2. Click the Close button
Ansoft High Frequency Structure Simulator v10 User’s Guide
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10.1
Example – Silicon Spiral Inductor
Create Reports
Create SS-parameter vs. Frequency
To Create a report:
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Terminal S Parameters
2. Display Type: Rectangular
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: Sweep1
2. Click the Y tab
1. Domain: Sweep
2. Category: Terminal SS-Parameters
3. Quantity: St(p1,p1), St(p2,p1)
4. Function: dB
5. Click the Add Trace button
3. Click the Done button
Ansoft High Frequency Structure Simulator v10 User’s Guide
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10.1
Example – Silicon Spiral Inductor
Create Reports (Continued)
Custom Equations – Output Variables
1.
2.
3.
Select the menu item HFSS > Results > Create Report
Create Report Window::
1. Report Type: Terminal S Parameters
2. Display Type: Rectangular
Im(Ynn )
3. Click the OK button
Qnn =
Traces Window::
Re(Ynn )
1. Click the Output Variables button
2. Output Variables dialog:
1. Name: Q11
2. Expression:
Category: Terminal Y Parameters
Quantity: Yt(p1,p1)
Function: im
Click the Insert Quantity into Expression button
Type: /
Quantity: Yt(p1,p1)
Function: re
Click the Insert Quantity into Expression button
3. Click the Add button
4. Repeat for Q22,
Q22 by replacing Yt(p1,p1) with Yt(p2,p2)
5. Click the Done button
3. Solution: Setup1: Sweep1
4. Domain: Sweep
5. Click the Y tab
1. Category: Output Variables
2. Quantity: Q11, Q22
3. Function: abs
4. Click the Add Trace button
6. Click the Done button
Ansoft High Frequency Structure Simulator v10 User’s Guide
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10.1
Example – Silicon Spiral Inductor
Create Reports (Continued)
Custom Equations – Output Variables
1.
2.
3.
Select the menu item HFSS > Results > Create Report
Create Report Window::
1. Report Type: Terminal S Parameters
2. Display Type: Rectangular
−1
3. Click the OK button
Lnn =
Traces Window::
2 ⋅ f ⋅ im(Ynn )
1. Click the Output Variables button
2. Output Variables dialog:
1. Name: L11
2. Expression:
Type: -1/(2*pi*freq*
Category: Terminal Y Parameters
Quantity: Yt(p1,p1)
Function: im
Click the Insert Quantity into Expression button
Type: )
3. Click the Add button
4. Click the Done button
3. Solution: Setup1: Sweep1
4. Domain: Sweep
5. Click the Y tab
1. Category: Output Variables
2. Quantity: Y11
3. Function: none
4. Click the Add Trace button
6. Click the Done button
Ansoft High Frequency Structure Simulator v10 User’s Guide
π
10.1-26
10.1
Example – Silicon Spiral Inductor
Port
Appendix – Alternative Lumped Ports
G
S
G
PEC Bridge
Ansoft High Frequency Structure Simulator v10 User’s Guide
10.1-27
10.1
Example – Silicon Spiral Inductor
Port
Appendix – Alternative Lumped Ports
G
S
G
gap
S
G
Lumped
Port
Ansoft High Frequency Structure Simulator v10 User’s Guide
G
gap
10.1-28
10.1
Example – Silicon Spiral Inductor
Port
Appendix – Alternative Lumped Ports
G
G
Via
S
S
G
G
Lumped Port
Via
Ground Bridge
Ansoft High Frequency Structure Simulator v10 User’s Guide
10.1-29
Presentation
Overview
Ansoft High Frequency Structure Simulator v10 – Training Seminar
1
P1-1
Presentation
Overview
Quick Example – Coax Tee
1
HFSS – High Frequency Structure Simulator
Full-Wave 3D field solver
Solves for the fields in an arbitrary volume
Coax Center Pin
Coax Dielectric
Outer Boundary
Coax Shield
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Presentation
Overview
1
Starting HFSS
Click the Microsoft Start button, select Programs,
Programs and select the Ansoft > HFSS 10 > HFSS 10
Or Double click on the HFSS 10 icon on the Windows Desktop
Adding a Design
When you first start HFSS a new project with a new design will be automatically added to the Project Tree.
Toolbar: Insert HFSS Design
To include additional designs into an existing project, select the menu item Project > Insert HFSS Design
Alternatively to open a new project with a new design manually, select the menu item File > New.
Ansoft High Frequency Structure Simulator v10 – Training Seminar
P1-3
Presentation
Overview
1
Ansoft Desktop
Menu
bar
Toolbars
3D Modeler
Window
Project
Manager
with project
tree
Progress
Window
Message
Manager
Status
bar
Coordinate Entry Fields
Ansoft High Frequency Structure Simulator v10 – Training Seminar
Property Window
P1-4
Presentation
Overview
1
Ansoft Desktop – Project Manager
Multiple Designs per Project
Multiple Projects per Desktop
Integrated Optimetrics Setup
Requires License for Analysis
Project Manager Window
Project
Design
Design Setup
Design Automation
•Parametric
•Optimization
•Sensitivity
•Statistical
Ansoft High Frequency Structure Simulator v10 – Training Seminar
Design Results
P1-5
Presentation
Overview
1
Ansoft Desktop – 3D Modeler
3D Modeler Window
Graphics
area
Model
3D Modeler
design tree
Edge
Vertex
Coordinate System (CS)
Plane
Context menu
Origin
Face
Model
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Presentation
Overview
1
Set Solution Type
To set the solution type:
1. Select the menu item HFSS > Solution Type
2. Solution Type Window:
1. Choose Driven Modal
2. Click the OK button
HFSS - Solution Types
Driven Modal - calculates the modal-based S-parameters. The S-matrix solutions will be expressed in terms of the
incident and reflected powers of waveguide modes.
Generalized S-parameters
Driven Terminal - calculates the terminal-based S-parameters of multi-conductor transmission line ports. The Smatrix solutions will be expressed in terms of terminal voltages and currents.
Eigenmode – calculate the eigenmodes, or resonances, of a structure. The Eigenmode solver finds the resonant
frequencies of the structure and the fields at those resonant frequencies.
Convergence
Driven Modal – Delta S for modal S-Parameters.
Driven Terminal – Delta S for the single-ended or differential nodal S-Parameters.
Eigenmode - Delta F
Ansoft High Frequency Structure Simulator v10 – Training Seminar
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Presentation
Overview
1
Set Model Units
To set the units:
1. Select the menu item 3D Modeler > Units
2. Set Model Units:
1. Select Units: mm
2. Click the OK button
Set Default Material
To set the default material:
1. Using the 3D Modeler Materials toolbar, choose Select
2. Select Definition Window:
1. Type pec in the Search by Name field
2. Click the OK button
Ansoft High Frequency Structure Simulator v10 – Training Seminar
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Presentation
Overview
1
3D Modeler – Create a Primitive
Point 1
Point 1
Grid Plane
Point 3
Base Rectangle
Point 2
Point 2
Coordinate Entry Fields
Point 3
The Coordinate Entry fields allow equations to be entered for position values.
Examples: 2*5, 2+6+8, 2*cos(10*(pi/180)).
Variables are not allowed in the Coordinate Entry Field
Note:
Note Trig functions are in radians
Ansoft High Frequency Structure Simulator v10 – Training Seminar
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Presentation
Overview
3D Modeler – Object Properties
Commands
1
Attributes
Commands
Attributes
Ansoft High Frequency Structure Simulator v10 – Training Seminar
P1-10
Presentation
Overview
1
3D Modeler – Attributes
Ansoft High Frequency Structure Simulator v10 – Training Seminar
P1-11
Presentation
Overview
1
Set Grid Plane
To set the Grid Plane:
Select the menu item 3D Modeler > Grid Plane > YZ
Create Coax Pin
To create the coax pin:
1. Select the menu item Draw > Cylinder
2. Using the coordinate entry fields, enter the center position
X:: 0.0,
0.0 Y:: 0.0,
0.0 Z:: 0.0, Press the Enter key
4.
Using the coordinate entry fields, enter the radius of the cylinder
dX:: 0.0,
0.0 dY:: .86.0,
.86.0 dZ:: 0.0
0 0, Press the Enter key
5.
Using the coordinate entry fields, enter the height of the cylinder
dX:: 6.0,
6.0 dY:: 0.0 dZ:: 0.0,
0.0 Press the Enter key
Continued on Next Page
Ansoft High Frequency Structure Simulator v10 – Training Seminar
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Presentation
Overview
1
Create Coax Pin (Continued)
To Parameterize the Height
1. Select the Command tab from the Properties window
2. Height: H
3. Press the Tab key
4. Add Variable Window
1. Value: 6mm
2. Click the OK button
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Coax_Pin
To set the color:
1. Select the Attribute tab from the Properties window.
2. Click the Edit button
To set the transparency:
1. Select the Attribute tab from the Properties window.
2. Click the OK button
To finish editing the object properties
1. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View
Ansoft High Frequency Structure Simulator v10 – Training Seminar
P1-13
Presentation
Overview
1
3D Modeler - Views
View > Modify Attributes >
Orientation – Predefined/Custom View Angles
Lighting – Control angle, intensity, and color of light
Projection – Control camera and perspective
Background Color – Control color of 3D Modeler background
View > Active View Visibility - Controls the display of: 3D Modeler
Objects, Color Keys, Boundaries, Excitations, Field Plots
View > Options – Stereo Mode, Drag Optimization, Color Key Defaults,
Default Rotation
View > Render > Wire Frame or Smooth Shaded (Default)
View > Coordinate System > Hide or Small (Large)
View > Grid Setting – Controls the grid display
Toolbar: Toggle Grid Visibility
Ansoft High Frequency Structure Simulator v10 – Training Seminar
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Presentation
Overview
1
Changing the View
Toolbar
Rotate Around
Current Axis
Zoom In/Out
Fit Selected
Predefined View Angles
Pan
Top
Fit All
Rotate Around
Rotate Around Screen Center
Model Center
Dynamic Zoom
Context Menu
Right
Left
Bottom
Shortcuts
Since changing the view is a frequently used operation, some useful shortcut keys exist. Press the
appropriate keys and drag the mouse with the left button pressed:
ALT + Drag – Rotate
In addition, there are 9 pre-defined view angles that can be selected by holding the ALT key and
double clicking on the locations shown on the next page.
Shift + Drag - Pan
ALT + Shift + Drag – Dynamic Zoom
Ansoft High Frequency Structure Simulator v10 – Training Seminar
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Presentation
Overview
1
Set Default Material
To set the default material:
Using the 3D Modeler Materials toolbar, choose vacuum
Create Coax
To create the coax:
1. Select the menu item Draw > Cylinder
2. Using the coordinate entry fields, enter the center position
X:: 0.0,
0.0 Y:: 0.0,
0.0 Z:: 0.0, Press the Enter key
4. Using the coordinate entry fields, enter the radius of the cylinder
dX:: 0.0,
0.0 dY:: 2.0,
2.0 dZ:: 0.0
0 0, Press the Enter key
5. Using the coordinate entry fields, enter the height of the cylinder
dX:: 6.0,
6.0 dY:: 0.0 dZ:: 0.0,
0.0 Press the Enter key
To Parameterize the Height:
1. Select the Command tab from the Properties window
2. Height: H
3. Click the OK button
To set the name:
1. Select the Attribute tab from the Properties window.
2. For the Value of Name type: Coax
3. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View
Ansoft High Frequency Structure Simulator v10 – Training Seminar
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Presentation
Overview
1
Create Excitation
Face Selection
Select the menu item Edit > Select > Faces
By moving the mouse, graphically highlight the top face of the Coax object
Click the left mouse button to select the face
Assign Excitation
Select the menu item HFSS > Excitations > Assign > Wave Port
1. Wave Port : General
1. Name: p1
2. Click the Next button
2. Wave Port : Modes
1. Click the Next button
3. Wave Port : Post Processing
1. Renormalize All Modes: Checked
2. Full Port Impedance: 50 Ohm
4. Click the Finish button
Ansoft High Frequency Structure Simulator v10 – Training Seminar
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1
Duplicate boundaries with geometry
1.
2.
Works with all boundaries and excitations
Select the menu item Tools > Options > HFSS Options
HFSS Options Window:
1. Click the General tab
Use Wizards for data entry when creating new boundaries:: Checked
Duplicate boundaries with geometry:: Checked
2. Click the OK button
Example:
Assign an Excitation to the face of an object
Duplicate the object around an axis three times
The Excitation is automatically duplicated
Ansoft High Frequency Structure Simulator v10 – Training Seminar
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Presentation
Overview
1
Set Object Selection
Set select to objects
1. Select the menu item Edit > Select > Objects
Create Tee
To create Tee:
1. Select the menu item Edit > Select All Visible. Or press the CTRL+A key.
2. Select the menu item, Edit > Duplicate > Around Axis.
1. Axis: Z
2. Angle: 90
3. Total Number: 3
4. Click the OK button
To fit the view:
1. Select the menu item View > Fit All > Active View.
Ansoft High Frequency Structure Simulator v10 – Training Seminar
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Presentation
Overview
1
Unite Conductors
Select Conductors
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Coax_Pin,
Coax_Pin, Coax_Pin_1, Coax_Pin_2
2. Click the OK button
Unite
1. Select the menu item 3D Modeler > Boolean > Unite
Unite Coax
Select Coax
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Coax, Coax_1, Coax_2
2. Click the OK button
Unite
1. Select the menu item 3D Modeler > Boolean > Unite
Ansoft High Frequency Structure Simulator v10 – Training Seminar
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Presentation
Overview
1
HFSS - Solution Setup
Creating an Analysis Setup
Add Solution Setup
To create an analysis setup:
1. Select the menu item HFSS > Analysis Setup > Add Solution Setup
2. Solution Setup Window:
1. Click the General tab::
Solution Frequency:: 10.0 GHz
2. Click the OK button
Picking the Adapt Frequency
See User Guide Chapter 2
Adapt Frequency
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1
Adding a Frequency Sweep
To add a frequency sweep:
Add Sweep
1. Select the menu item HFSS > Analysis Setup > Add Sweep
1. Select Solution Setup: Setup1
2. Click the OK button
2. Edit Sweep Window:
1. Sweep Type:: Fast
2. Frequency Setup Type:: Linear Step
Start: 1.0 GHz
Stop:: 10.0 GHz
Step:: 0.1 GHz
Save Fields: Checked
3. Click the OK button
HFSS – Frequency Sweep
Discrete – Solves using adaptive mesh at every frequency
Matrix Data and Fields at every frequency in sweep
Fast - ALPS
Matrix Data and Fields at every frequency in sweep
Interpolating – Adaptively determines discrete solve
points using the adaptive mesh
Matrix Data at every frequency in sweeps
Fields at last adaptive solution
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Presentation
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1
Save Project
To save the project:
1. In an Ansoft HFSS window, select the menu item File > Save As.
2. From the Save As window, type the Filename: hfss_coax_tee
3. Click the Save button
Analyze
Model Validation
To validate the model:
1. Select the menu item HFSS > Validation Check
2. Click the Close button
Note: To view any errors or warning messages, use the Message Manager.
Analyze
To start the solution process:
1. Select the menu item HFSS > Analyze All
Validate
Ansoft High Frequency Structure Simulator v10 – Training Seminar
Analyze All
P1-23
Presentation
Overview
1
Create Reports
To create a report:
1. Select the menu item HFSS > Results > Create Report
2. Create Report Window::
1. Report Type: Modal S Parameters
2. Display Type: Rectangular
3. Click the OK button
3. Traces Window::
1. Solution: Setup1: Sweep1
2. Domain: Sweep
3. Click the Y tab
1. Category: Terminal S Parameter
2. Quantity: S(p1,p1), S(p1,p2), S(p2,p3)
3. Function: dB
4. Click the Add Trace button
4. Click the Done button
Ansoft High Frequency Structure Simulator v10 – Training Seminar
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Presentation
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1
Field Overlays
To create a field plot:
1. Select an object to overlay fields
1. Select the menu item Edit > Select > By Name
2. Select Object Dialog,
1. Select the objects named: Coax
2. Click the OK button
2. Select the menu item HFSS > Fields > Fields > E > Mag_E
3. Create Field Plot Window
1. Solution: Setup1 : LastAdaptive
2. Quantity: Mag_E
3. In Volume: All
4. Click the Done button
To modify the attributes of a field plot:
1. Select the menu item HFSS > Fields > Modify Plot Attributes
2. Select Plot Folder Window:
1. Select: E Field
2. Click the OK button
3. E-Field Window:
1. Click the Scale tab
1. Select Use Limits
2. Min: 5
3. Max: 25000
4. Scale: Log
2. Click the Plot tab
1. IsoValType: IsoValSurface
2. Click the Apply button.
4. Click the Close button
Ansoft High Frequency Structure Simulator v10 – Training Seminar
P1-25
Presentation
Overview
1
What is HFSS?
HFSS – High Frequency Structure Simulator
Arbitrary 3D Volumetric Full-Wave Field Solver
Ansoft Desktop
Advanced ACIS based Modeling
True Parametric Technology – Dynamic Editing
Powerful Report Generation
Dynamic Field Visualization
Design Flow Automation
Optimetrics/Ansoft Designer/AnsoftLinks
Advanced Material Types
Frequency Dependent Materials
Non-linear Materials
Anisotropic Materials
Advanced Boundary Conditions
Radiation and Perfectly Matched Layers
Symmetry, Finite Conductivity, Infinite Planes, RLC, and Layered Impedance
Master/Slave – Unit Cells
Advanced Solver Technology
Automatic Conformal Mesh Generation
Adaptive Mesh Generation
Internal/External Excitations – Includes Loss
ALPS Fast Frequency Sweep
Eigenmode
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1
Common HFSS Applications
Antenna
Planar Antennas - Patches, Dipoles, Horns, Conformal Cell Phone Antennas, Spirals
Waveguide – Circular/Square Horns
Wire – Dipole, Helix
Arrays - Infinite Arrays, Frequency Selective Surfaces (FSS) & Photonic Band Gaps (PBG)
Radar Cross Section (RCS)
Microwave
Filters – Cavity Filters, Microstrip, Dielectric
EMC/EMI – Shield Enclosures, Coupling, Near- or Far-Field Radiation
Connectors – Coax, SFP/XFP, Backplane, Transitions
Waveguide – Filters, Resonators, Transitions, Couplers
Silicon/GaSa - Spiral Inductors, Transformers
Signal Integrity/HighIntegrity/High-Speed Digital
Package Modeling – BGA, QFP, Flip-Chip
PCB Board Modeling – Power/Ground planes, Mesh Grid Grounds, Backplanes
Connectors – SFP/XFP, VHDM, GBX, NexLev, Coax
Transitions – Differential/Single-ended Vias
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Overview
1
What Information does HFSS Compute?
Matrix Data
Modal/Terminal/Differential
S-, Y-, and Z-Parameters
VSWR
Excitations
Complex Propagation Constant (Gamma)
Zo
Full-Wave Spice
Full-Wave Spice – Broadband Model
Lumped RLC – Low Frequency Model
Partial Fraction - Matlab
Export Formats – HSPICE, PSPICE, Cadence Spectre, and Maxwell SPICE
Common Display Formats:
Rectangular, Polar
Smith Chart
Data Tables
Common Output Formats:
Neutral Models Files (NMF) (Optimetrics only)
Parametric Results
Touchstone, Data Tables, Matlab,
Citifile
Graphics – Windows Clipboard
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1
What Information does HFSS Compute? (Continued)
Fields
Modal/Terminal/Differential
Electric Field
Magnetic Field
Current (Volume/Surface)
Power
Specific Absorption Rate
Radiation
2D/3D Far-/Near-Fields
Arrays – Regular and Custom Setups
RCS
Field Calculator
User Defined Field Calculations
Common Display Formats
Volume
Surface
Vector
2D Reports – Rectangular, Polar, Radiation Patterns
Common Output Formats:
Animations – AVI, GIF
Data Tables
Graphics – Windows Clipboard, BMP, GIF, JPG, TIFF, VRML
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1
What is the Technology Behind the HFSS Field Solver?
Volumetric Field Solver
Type: FullFull-Wave
Solution Method: 3D Finite Element Method (FEM)
Accuracy:
Accuracy If there were no limits on the size of the matrix and on the number of digits
for computation, there would be no limit to the accuracy of the Finite Element Method!
Mesh Type: Conformal
Vertex:
Vertex Explicitly Solved
Mesh Element: Tetrahedron
Mesh Process: Adaptive
Edge:
Edge Explicitly Solved
Convergence: Complex Magnitude
Change in SS-Parameters (Delta S)
Excitations - Port Solver
Face:
Face Interpolated
Solution Method: 2D Finite Element Method
Mesh Process: Adaptive
Frequency Sweeps
Fast Frequency Sweep: ALPS
Matrix Data and Fields at every frequency in sweep
Supports sweeps as large as 10000 data points from a single solution.
Interpolating Sweep
Adaptive Discrete Sweep with curve fitting
Supports sweeps as large as 10000 data points. Number of discrete solution
points varies with response.
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1
Initial Mesh
Adaptive Refinement
Adaptive Mesh Refinement automatically
tunes the mesh to the electrical
performance of the device. This ensures
simulations are correct the first time.
Mesh Convergence:
Convergence Real-Time update of
performance per adaptive solution.
Matrix Data
Fields
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1
The Process
Design
Solution Type
1.1. Boundaries
1. Parametric Model
Geometry/Materials
1.2. Excitations
4.1 Mesh
Operations
2. Analysis
Solution Setup
Frequency Sweep
Mesh
Refinement
Analyze
Solve
3. Results
NO
2D Reports
Fields
Converged
4. Solve Loop
YES
Update
Ansoft High Frequency Structure Simulator v10 – Training Seminar
Finished
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Presentation
Overview
1
Initial Solution
Initial Mesh
Seeding and
Lambda Refinement
(Single Frequency)
Port Solution
(Adaptive)
Ports Only &
Frequency Sweep
Full Volumetric Solution
(S(S-Parameters/EParameters/E-Fields)
No Adaptive Meshing
Refine Mesh
(Gradient of EE-Field
at Single Frequency)
Adaptive Mesh Loop
No
Check Convergence
(Delta S)
YES
Frequency Sweep
Full Volumetric Solution
(S(S-Parameters/EParameters/E-Fields)
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Overview
1
3D Modeler – Model Tree
Select menu item 3D Modeler > Group by Material
Material
Object
Object Command History
Grouped by Material
Ansoft High Frequency Structure Simulator v10 – Training Seminar
Object View
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Presentation
Overview
1
3D Modeler – Commands
Parametric Technology
Dynamic Edits - Change Dimensions
Add Variables
Project Variables (Global) or Design Variables (Local)
Animate Geometry
Include Units – Default Unit is meters
Supports mixed Units
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1
3D Modeler – Primitives
2D Draw Objects
The following 2D Draw objects are available:
Line, Spline, Arc, Equation Based Curve,
Rectangle, Ellipse, Circle, Regular Polygon,
Equation Based Surface
3D Draw Objects
The following 3D Draw objects are available:
Box, Cylinder, Regular Polyhedron
Cone, Sphere, Torus, Helix, Spiral, Bond
Wire
Toolbar: 2D Objects
Toolbar: 3D Objects
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1
Splitting versus Subtracting objects
Two or more true surface objects overlapping
Perform Split of objects for Meshing purposes
1. Move coordinate system to a desired position
2. Select multiple objects to split
3. Select 3D Modeler > Boolean > Split
4. Select desired split plane and Both sets of objects to keep.
Relative CS
Original Model
(overlaps between two cylinders)
No need to Copy->Subtract->Paste
Recommended approach
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1
3D Modeler – Boolean Operations/Transformations
3D Modeler > Boolean >
Unite – combine multiple primitives
Unite disjoint objects (Separate
Separate Bodies to separate)
Subtract – remove part of a primitive from another
Intersect–
Intersect keep only the parts of primitives that overlap
Split – break primitives into multiple parts along a plane (XY, YZ, XZ)
Split Crossing Objects – splits objects along a plane (XY, YZ, XZ) only where they intersect
Separate Bodies – separates objects which are united but not physically connected into individual
objects
Toolbar: Boolean
3D Modeler > Surfaces > Move Faces – Resize or Reposition an objects face along a normal or vector.
Edit > Arrange >
Move – Translates the structure along a vector
Rotate – Rotates the shape around a coordinate axis by an angle
Mirror – Mirrors the shape around a specified plane
Offset – Performs a uniform scale in x, y, and z.
Toolbar: Arrange
Edit > Duplicate >
Along Line – Create multiple copies of an object along a vector
Around Axis – Create multiple copies of an object rotated by a fixed angle around the x, y, or z axis
Mirror - Mirrors the shape around a specified plane and creates a duplicate
Toolbar: Duplicate
Edit > Scale – Allows non-uniform scaling in the x, y, or z direction
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1
3D Modeler - Selection
Selection Types
Object (Default)
Face
Edge
Vertex
Selection Modes
All Objects
All Visible Object
By Name
Highlight Selection Dynamically – By default, moving the mouse pointer over an object will dynamically
highlight the object for selection. To select the object simply click the left mouse button.
Multiple Object Selection – Hold the CTRL key down to graphically select multiple objects
Next Behind – To select an object located behind another object, select the front object, press the b key to get
the next behind. Note: The mouse pointer must be located such that the next behind object is under the
mouse pointer.
To Disable: Select the menu item Tools > Options > 3D Modeler Options
From the Display Tab,
Tab uncheck Highlight selection dynamically
Selected
Dynamically Highlighted
(Only frame of object)
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1
3D Modeler – Moving Around
Step 1: Start Point
Step 2: Hold X key and select vertex point
Edge Center Snap
Toolbar: Snap Mode
Step 3: CTRL+Enter Keys set a local reference
Ansoft High Frequency Structure Simulator v10 – Training Seminar
Step 4: Hold Z key and set height
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3D Modeler – Coordinate System
Can be Parameterized
Working Coordinate System
Currently selected CS. This can be a local or global CS
Global CS
The default fixed coordinate system
Relative CS
User defined local coordinate system.
Offset
Rotated
Toolbar: Coordinate System
Both
Face CS (setting available to automatically switch to face coordinate system in the 3D Modeler Options)
Step 1: Select Face
Step 2: Select Origin
Cone created with Face CS
Step 3: Set X-Axis
New Working CS
Ansoft High Frequency Structure Simulator v10 – Training Seminar
Change Box Size and Cone is
automatically positioned with
the top face of the box
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1
HFSS – Matrix Data
HFSS > Results > Solution Data
Export
NMF, Touchstone, Data Tables, Citifile, MATLAB (*.m)
NOTE: Make sure the Simulation is set to a Sweep before exporting. The Adaptive Passes will only export a
single frequency point.
Equivalent Circuit Export
HSPICE, PSPICE, Spectre, Maxwell SPICE
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1
Results – Data Management
HFSS > Results > Browse Solutions
Solved model variations are retained.
Unless otherwise notified by HFSS.
HFSS > Results > Clean Up Solutions
HFSS > Results > Import Solutions
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Overview
1
Results – Create Reports
HFSS > Results > Create Report
Output Variables
User Defined Equations
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Overview
1
Fields
Select Object Volume, Surface, or Line to display fields
HFSS > Fields > Plot Fields >
Modify Plot – Solution/Frequency/Qty
Plot Attributes
Edit Sources – Change Excitation
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1
Mesh Display
Field Overlay
1. Select an object
2. Select the menu item HFSS > Fields > Plot Mesh
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1
Menu Structure
Draw – Primitives
3D Modeler – Settings and Boolean Operations
Edit – Arrange, Duplicate
HFSS – Boundaries, Excitations, Mesh Operations, Analysis Setup, Results
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1
Measure
3D Modeler > Measure >
Position – Points and Distance
Length – Edge Length
Area – Surface Area
Volume – Object Volume
Position Points
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1
Options – General
Tools > Options > General Options
Temp Directory – Location used during solution process
Make sure it is at least 512MB free disk.
Options - HFSS
Tools > Options > HFSS Options > Solver
Number of Processors – Requires additional license
Desired RAM Limit – leave it unchecked for auto-detect
Maximum RAM Limit – leave it unchecked for auto-detect
Process Priority – set the simulation priority from Critical
(highest) to Idle (lowest)
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1
Converting Older HFSS Projects (pre-HFSS v9) to HFSS v10
From HFSS v10.0,
v10.0
1. Select the menu item File > Open
2. Open dialog
1. Files of Type: Ansoft Legacy EM Projects (.cls
(.cls)
cls)
2. Browse to the existing project and select the .cls file
3. Click the Open button
What is Converted?
Converts Entire Model: Geometry, Materials, Boundaries,
Sources and Setup
Solutions, Optimetrics projects and Macros are not converted
Legacy License
Existing customers using HFSS v9.2.1 should have received legacy licenses with the new v10.0 licenses.
These licenses allow you to run either v10.0 or v9.2.1
Contact your Account Manager if this feature is not available
NOTE: Once a project is saved in v10 it can no longer be opened in v9
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Overview
1
HFSS v10 Enhancements
From import of complex solid models to HFSS analysis is a multi-stage process, each step of which
plays an important role
import healing meshing model resolution analysis
Applications Include:
High-Speed PCBs
Complex Connectors
Ansoft High Frequency Structure Simulator v10 – Training Seminar
Microwave Devices
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1
HFSS v10 Enhancements
Healing Geometry
Key Edit Features
Auto/Manual Import Healing
3D Model Analysis – 3D Modeler/Analyze
Face, Object , Area analysis based on user inputs
List of problems (faces, edges, vertices)
Auto Zoom In into region where problem exists
Remove Face
Remove Edge
Remove Sliver
Remove Vertices
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Overview
1
HFSS v10 Enhancements
Improved Mesh Generation
Significantly improved mesh generation algorithms
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Presentation
Overview
1
HFSS v10 Enhancements
Model Resolution
Mesh before:
before
184,675 tets
Mesh after:
24,691 tets
Length=0.1 mm
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Overview
1
HFSS v10 Enhancements
New dynamic links with HFSS and between Designer/Nexxim and SIWave
New incident wave: Spherical, cylindrical, line dipole, Gaussian beam, etc
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1
HFSS v10 Enhancements
Distributed Analysis
1) The graphical user interface enables users to select
computer addresses for analysis distribution
2) Automated parser management and reassembly of data
3) Parametric tables and studies
4) Frequency sweeps for discrete, fast, and interpolating
5) Per license, distributed analysis allows up to 10 parallel
simulations on remote machines, providing near-linear
reduction of simulation run times
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Overview
1
Recommended Service Packs (SP) – PC only
Microsoft Windows XP - SP2 or higher
Microsoft Windows 2000 – SP4 or higher
Updating Drivers
Update your DirectX drivers to ver9.0c
http://www.microsoft.com/directx
Update your video drivers to the latest available from the card manufacturer
Memory allocation HFSS v9.2
With the release of HFSS v9.2 you can access sup to 3GB of Ram on PC
All about 3GB switch, supported OS
http://support.microsoft.com/default.aspx?scid=kb;en-us;291988
How to use /3GB switch
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/ddtools/hh/ddtools/bootini_1fcj.asp
Possible problems
http://support.microsoft.com/default.aspx?scid=kb;en-us;328269
Increasing Memory allocation HFSS v10
With the release of HFSS v10 on a 64bit operating system theoretically there is no RAM limitation
Practically you can access up to 32GB of RAM due to hardware limitations
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1
Unix Operating Systems
HPUX 11.0
Solaris 2.8 and 2.9
Note: Requires OpenGL
Note: Please perform required OS updates outlined in readme file on the CD
Common Desktop (CDE)
There is an issue with HFSS dialog boxes moving behind the main window. The following instructions describe
how to prevent this:
Select Tools > Desktop Controls
Select Window Style Manager
From the Style Manager – Window
Uncheck Allow Primary Windows on Top
Ansoft High Frequency Structure Simulator v10 – Training Seminar
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1
Project Files
Everything regarding the project is stored in an ascii file
File: <project_name>.
project_name>.hfss
>.hfss
Double click from Windows Explorer will open and launch HFSS v10
Results and Mesh are stored in a folder named <project_name>.
project_name>.hfssresults
>.hfssresults
Lock file: <project_name>.
project_name>.lock.hfss
>.lock.hfss
Created when a project is opened
Auto Save File: <project_name>.
project_name>.hfss.auto
>.hfss.auto
When recovering, software only checks date
If an error occurred when saving the auto file, the date will be newer then the original
Look at file size (provided in recover dialog)
Scripts
Default Script recorded in v10
Visual Basic Script
Remote Solve (Windows Only)
Tools > Options > General Options >
Analysis Options
Uses DCOM
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1
Ansoft Designer SV
Ansoft Designer™ SV is a full-featured subset of Ansoft's commercially distributed Ansoft Designer
Ansoft Designer SV contains a complete high-frequency linear circuit simulator, schematic and layout design entry,
powerful design utilities, and post-processing, all integrated in an easy-to-use environment. The software also
includes a complete set of linear distributed transmission line models, discontinuities, vendor component parts, and
ideal circuit elements.
Ansoft Designer SV allows the simulation of S-, Y-, and Z-parameters, group delay, noise figure, and stability
circles of RF and microwave circuits. Utilities include real-time tuning, filter and TRL synthesis, and Smith Tool
matching. Post-processing includes rectangular plots, Smith Charts, polar plots, and data tables. Additionally,
Ansoft Designer SV comes with a set of real-world examples.
Free Download:
Download www.ansoft.com/ansoftdesignersv
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1
For Technical Support
The following link will direct you to the Ansoft Support Page. The Ansoft Support Pages provide additional
documentation, training, and application notes. Web Site: http://www.ansoft.com/support.cfm
Application Engineers for North America
The names and numbers in this list may change without notice
9-4 EST:
Pittsburgh, PA
(412) 261-3200 x0 – Ask for Technical Support
Burlington, MA
(781) 229-8900 x0 – Ask for Technical Support
9-4 PST:
San Jose, CA
(408) 261-9095 x0 – Ask for Technical Support
Portland, OR
(503) 906-7944 or (503) 906-7947
El Segundo, CA
(310) 426-2287 – Ask for Technical Support
Ansoft High Frequency Structure Simulator v10 – Training Seminar
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Boundary/Excitations - Overview
2
Why are They Critical?
For most practical problems, the solution to Maxwell’s equations requires a
rigorous matrix approach such as the Finite Element Method (FEM) which
is used by Ansoft HFSS.
The wave equation solved by Ansoft HFSS is derived from the
differential form of Maxwell’s equations.
For these expressions to be valid, it is assumed that the field vectors are:
single-valued,
bounded, and have a
continuous distribution (along with their derivatives)
∇×
Along boundaries of media or at sources,
Field vectors are discontinuous
Derivatives of the field vectors have no meaning
∂B
∂t
∂D
∇×H = J +
∂t
∇⋅D= ρ
E=−
∇⋅B=0
Boundary Conditions define the field behavior across discontinuous boundaries
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Boundary/Excitations - Overview
2
Why do I Care?
They Force the fields to align with the definition of the boundary condition
As a user I should be asking
What assumptions, about the fields, do the boundary conditions make?
Are these assumptions appropriate for the structure being simulated?
Model Scope
To reduce the infinite space of the real world to a finite volume, Ansoft HFSS automatically
applies a boundary to the surface surrounding the geometric model
Outer boundary
Default Boundary: Perfect E
Model Complexity
To reduce the complexity of a model, the boundary conditions can be used to improve the:
Solution Time
Computer Resources
Failure to understand boundary conditions may lead to inconsistent results
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Boundary/Excitations - Overview
2
What are Common Ansoft HFSS Boundary Conditions?
Excitations
Wave Ports (External)
Lumped Ports (Internal)
Surface Approximations
Perfect E or Perfect H Surface
Finite Conductivity Surface
Impedance Surface
Symmetry Planes
Radiation Surface
Largely the users responsibility
Material Properties
Boundary between two dielectrics
Finite Conductivity of a conductor
Ansoft High Frequency Structure Simulator v10 – Training Seminar
Transparent to the user
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Boundary/Excitations - Overview
2
Surface Approximations
Perfect E – Forces the electric field perpendicular to the surface
Outer Surface – Default Boundary
PEC/Perfect Conductor Material Property
Model complexity: Reduced by eliminating conductor loss
Perfect H – Forces the electric field tangent to the surface
Perfect E Surface
Perfect H Surface
Finite Conductivity – Lossy electric conductor.
Forces the tangential electric field at the surface to: Zs(n x Htan).
The surface impedance (Zs) is equal to, (1+j)/(δσ),
Model complexity: Reduced by eliminating conductor thickness
Impedance Surface – Represent surfaces of a known impedance
Forces the tangential electric field at the surface to: Zs(n x Htan).
The surface impedance (Zs) is equal to, Rs + jXs (Ohms/Square)
Layered Impedance – Models multiple thin layers in a structure as an Impedance Surface
Lumped RLC – Parallel combination
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Boundary/Excitations - Overview
2
Surface Approximations (Continued)
Symmetry Planes – Enable you to model only part of a structure
Perfect E or Perfect H Symmetry Planes
Must be exposed to the outer surface
Must be on a planar surface
Remember! Mechanical Symmetry does not Equal Electrical Symmetry
Model complexity: Reduced by eliminating part of the solution volume
Perfect E Symmetry
Full Model
Perfect H Symmetry
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Boundary/Excitations - Overview
2
Surface Approximations (Continued)
Radiation Surface – Allows waves to radiate infinitely far into space.
The boundary absorbs wave at the radiation surface
Can be placed on arbitrary surfaces
Accuracy depends on
The distance between the boundary and the radiating object
The radiation boundary should be located at least one-quarter of a wavelength
from a radiating structure. If you are simulating a structure that does not radiate,
the boundary can be located less then one-quarter of a wave length (The validity
of this assumption will require your engineering judgment).
The incident angle
The radiation boundary will reflect varying amounts of energy depending on the
incidence angle. The best performance is achieved at normal incidence. Avoid
angles greater then ~30degrees. In addition, the radiation boundary must remain
convex relative to the wave.
Perfectly Matched Layer (PML) – Allows waves to radiate infinitely far into space.
Not a Boundary Condition. Fictitious materials that fully absorb the electromagnetic fields
impinging upon them. These materials are complex anisotropic.
Types
Free Space Termination or Reflection Free Termination
Can only be placed on planar surface
Model complexity: They do not suffer from the distance or incident angle problems of
Radiation boundaries but should be place at least one-tenth of a wave length from
strong radiators
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Boundary/Excitations - Overview
2
Surface Approximations (Continued)
Infinite Ground Planes – Simulate the effects of an infinite ground plane
Only affects the calculation of near- or far-field radiation during post processing
Types: Perfect E, Finite Conductivity, or Impedance Surface
Frequency Dependent Boundary Conditions
The following boundary parameters can be assigned an expression that includes Freq:
Finite Conductivity
Impedance
Lumped RLC
Layered Impedance
Supported Frequency Sweeps
Single Frequency
Discrete Sweep
Interpolating Sweep
Ansoft High Frequency Structure Simulator v10 – Training Seminar
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Boundary/Excitations - Overview
2
Excitations
Ports are a unique type of boundary condition
Allow energy to flow into and out of a structure.
Defined on 2D planar surface
Arbitrary port solver calculates the natural field patterns or modes
Assumes semi-infinitely long waveguide
Same cross-section and material properties as port surface
2D field patterns serve as boundary conditions for the full 3D problem
Excitation Types
Wave Port (Waveguide) – External
Recommended only for surfaces exposed to the background
Supports multiple modes (Example: Coupled Lines) and deembedding
Compute Generalized S-Parameters
Port 4
Frequency
dependent
Characteristic
Impedance
(Zo)
Measurements
Constant Zo
Perfectly matched at every frequency
Lumped Port – Internal
Recommended only for surfaces internal to geometric model
Single mode (TEM) and no deembedding
Normalized to a constant user defined Zo
Ansoft High Frequency Structure Simulator v10 – Training Seminar
Port 1
Port 3
Port 2
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Boundary/Excitations - Overview
2
Excitations (Continued)
Wave Equation
The field pattern of a traveling wave inside a waveguide can be determined by solving
Maxwell’s equations. The following equation that is solved by the 2D solver is derived directly
from Maxwell’s equation.
 1

∇ ×  ∇ × E ( x, y ) − k02ε r E ( x, y ) = 0
 µr

where:
E(x,y) is a phasor representing an oscillating electric field.
k0 is the free space wave number,
µr is the complex relative permeability.
εr is the complex relative permittivity.
To solve this equation, the 2D solver obtains an excitation field pattern in the form of a phasor
solution, E(x,y). These phasor solutions are independent of z and t; only after being multiplied
by e-γz do they become traveling waves.
Also note that the excitation field pattern computed is valid only at a single frequency. A
different excitation field pattern is computed for each frequency point of interest.
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Boundary/Excitations - Overview
2
Excitations (Continued)
Modes, Reflections, and Propagation
It is also possible for a 3D field solution generated by an excitation signal of one specific
mode to contain reflections of higher-order modes which arise due to discontinuities in a high
frequency structure.
If these higher-order modes are reflected back to the excitation port or transmitted onto
another port, the S-parameters associated with these modes should be calculated.
If the higher-order mode decays before reaching any port—either because of attenuation due
to losses or because it is a non-propagating evanescent mode—there is no need to obtain the
S-parameters for that mode.
Wave Ports Require a Length of Uniform Cross Section
Ansoft HFSS assumes that each port you define is connected to a semi-infinitely long
waveguide that has the same cross section as the Wave Port
no uniform cross section
at Wave Ports
Ansoft High Frequency Structure Simulator v10 – Training Seminar
uniform cross section
added for each Wave Port
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Boundary/Excitations - Overview
2
Excitations (Continued)
Wave Port Boundary Conditions
Perfect E or Finite Conductivity
Default: All outer edges are Perfect E boundary.
Port is defined within a waveguide.
Easy for enclosed transmission lines: Coax or Waveguide
Challenging for unbalanced or non-enclosed lines: Microstrip, CPW, Slotline, etc.
Symmetry or Impedance
Recognized at the port edges
Radiation
Default interface is a Perfect E boundary
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Boundary/Excitations - Overview
2
Excitations (Continued)
Lumped Port Boundary Conditions
Perfect E or Finite Conductivity
Any port edge that interfaces with a conductor or another port edge
Perfect H
All remaining port edges
Perfect E
Perfect H
Perfect H
Perfect E
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Boundary/Excitations - Overview
2
Excitations (Continued)
Excitation – Calibration
Ports must be calibrated to ensure consistent results. Determines:
Direction and polarity of fields
Voltage calculations.
Solution Type: Driven Modal
Expressed in terms of the incident and reflected powers of the waveguide modes.
Definition not desirable for problems having several propagating quasi-TEM modes
Coupled/Multi-Coupled Transmission Lines
Always used by the solver
Calibration: Integration Line
Phase between Ports
Modal voltage integration path: Zpi, Zpv, Zvi
Solution Type: Driven Terminal
Linear combination of nodal voltages and currents for the Wave Port.
Equivalent transformation performed from Modal Solution
Calibration: Terminal Line
Polarity
Nodal voltage integration path
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Boundary/Excitations - Overview
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Example Solution Types:
Mode 1
(Even Mode)
Integration Line
Mode 2
(Odd Mode)
Integration Line
Port1
Modal
Port2
2 Modes
2 Modes
Modes to Nodes
Transformation
T1
T2
T1
SPICE
Differential Pairs
Port1
T2
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Terminal
Port2
T2
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Application of Boundary Conditions - Case 1
Emulate laboratory measurements
Verification/Validation before production
Picture courtesy of Delphi
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Picture courtesy of Tektronix
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Application of Boundary Conditions - Case 2
Isolate part of a structure (i.e. Exciting arbitrary transmission lines)
Not physically possible to measure in the laboratory
Full-Wave analysis not required for total system
Or total system too complex
Design work/Component level optimization
Post production problem solving
Total System
Isolated Component – Via Transition
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Example Structure
Coax to Stripline
LAYER 1 (TOP SIDE)
LAYER 2 (SIGNAL)
LAYER 3 (BOTTOM SIDE)
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Material Properties
All 3D (Solid) objects have material definitions
To complete the model shown previously we must include the air
that surrounds the structure.
air
Note: Substrate/Air boundary
included in structure
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Remember! Material Boundary conditions are transparent to the user
They are not visible in the Project Tree
Example Material Boundary: Conductors Surface Approximations
Perfect Conductors Perfect E Boundary (Boundary Name: smetal)
Forces E-Field perpendicular to surface
Lossy Conductors Finite Conductivity Boundary
Forces tangential E-Field to ((1+j)/(δσ))(n x Htan).
Assumes one skin depth – User must manually force Ansoft HFSS to
solve inside lossy conductors that are ≤ a skin depth
smetal
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Surface Approximations
Background or Outer Boundary
Not visible in the Project Tree
Any object surface that touches it Perfect E Boundary
Default boundary applied to the region surrounding the geometric model
Model is encased in a thin metal layer that no fields propagate through
outer
Override with
Radiation Boundary
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What Port Type Should I Use?
Example is easy decision
Port touches background (External)
Cross Section is Coax (Enclosed Transmission Line)
Wave Port
Solution Type: Driven Terminal
SPICE Output
Identify Port Type &
Cross Section
Assign Excitation &
Calibrate Port
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Define Default
Post Processing
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Is it Really that Simple?
Yes, but the geometric model was setup with several considerations
1. Only the face of the coax dielectric was selected for the port face
Port Boundary conditions define outer conductor
Material Definitions define inner conductor
2.
Uniform port cross-section
Only supports a single mode
Higher-order modes caused by reflections would attenuate before port
Modes attenuate as a function of e-αz, assuming propagation in the z-direction.
Required distance (uniform port length) depends on modes propagation constant.
Uniform crosscross-section
Rule of Thumb: 5x
Critical Distance
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How often is the Setup that Simple?
If you are emulating laboratory measurements? [Case 1 ]
Most of the time!
Laboratory equipment does not directly connect to arbitrary transmission
lines
Exceptions
Emulating Complex Probes with a Port Understanding of Probe
If you are isolating part of a structure? [Case 2 ]
For “real” designs - usually only by dumb luck!
User Must Understand and/or Implement Correctly:
1. Port Boundary conditions and impact of boundary condition
2. Fields within the structure
3. Assumptions made by port solver
4. Return path
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Side Note: Problems Associated with Correlating Results [Case 2]
Can be broken into two categories of problems
1. Complex Structure
BGA, Backplane, Antenna Feed, Waveguide “Plumbing”, etc
Most common problems result from
Measurement setup – Test fixtures, deembedding, etc.
Failing to understand the fields in the structure Boundary Problem
Return path problems – Model truncation
2.
Simple Structures
Uniform transmission lines
Equations or Circuit Elements
Most common problems result from
Improper use of default or excitation boundary conditions
Failure to understand the assumptions used by “correct” results
(Equations or Circuit Elements)
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Why are they critical?
Any current injected into a system must return to the source
DC
Chooses path of least resistance
AC
Chooses path of least inductance
A signal propagates between the signal trace and its reference plane
Reference plane is just as important as signal trace!
Why do I care?
Many real designs have nonideal return paths
These effects are only captured by full-wave simulators
Isolating parts of a structure
Failure to maintain the correct return path will
Limit correlation to measurements
Mask or create design problems
Port and Boundary setup is the most common source of error in model setup
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Port2
2
Port3
No DC
Return Path
Port1
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Port2
2
Port3
DC
Return Path
Port1
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DC & RF
Return Path
S21
S31
S11
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Isolate part of structure - Case 2
Isolate Transition
Deembed
Recombine using Ansoft Designer - Circuit
Wave Port
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Ansoft Designer - Circuit
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What went wrong?
Isolate Port from Discontinuity?
Yes
Uniform Cross-Section?
NO – The cross section of the port (including its boundaries) is not maintained
Maintain Return Path?
NO – Boundary on port shorts the planes together at edges
Identical to placing vias at port edge!
All Modes Accounted for?
NO – Did not consider Parallel Plate mode
Even if we did, the via (port edge) cuts off mode Reason vias are used!
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2 Terminals
Parallel
Plate
Mode Matching
Ansoft Designer - Circuit
Stripline
Wave Port
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Lumped Port
Port Influences
Results
No DC
Return Path
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Signal
GND
Power
SIDE
T2
T1
T3
Lumped Gap Port
G
GND
P
Power
Terminal Line
TOP
BOTTOM
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Lumped Gap Port
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Differential Lumped Gap Ports
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Port
G
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G
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Microstrip Port Sizing Guidelines
Assume width of microstrip trace is w
Assume height of substrate dielectric is h
Port Height Guidelines
Between 6h and 10h
Tend towards upper limit as dielectric constant drops and more fields exist in air rather than substrate
Bottom edge of port coplanar with the upper face of ground plane
(If real structure is enclosed lower than this guideline, model the real structure!)
Port Width Guidelines
10w, for microstrip profiles with w ≥ h
5w, or on the order of 3h to 4h, for microstrip profiles with w < h
10w, w ≥ h
or
5w (3h to 4h), w < h
6h to
10h
w
h
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Stripline Port Sizing Guidelines
Assume width of stripline trace is w
Assume height of substrate dielectric is h
Port Height Guidelines
Extend from upper to lower groundplane, h
Port Width Guidelines
8w, for microstrip profiles with w ≥ h
5w, or on the order of 3h to 4h, for microstrip profiles with w < h
Boundary Note: Can also make side walls of port Perfect H boundaries
8w, w ≥ h
or
5w (3h to 4h), w < h
w
h
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