R&S®ZV-WR02/WR03/-WR05 Technical Information

R&S®ZV-WR02/WR03/-WR05 Technical Information
1307.7274.92 – 03
Test and Measurement Division
Technical Information
®
R&S ZV-WR02 / WR03 / WR05
Calibration Kits
This technical information describes the following calibration kits:
R&S® ZV-WR02 (without Sliding Match standard), stock no. 1314.5550.10
R&S® ZV-WR03 (without Sliding Match standard), stock no. 1307.7300.30
R&S® ZV-WR03 (with Sliding Match standard), stock no. 1307.7300.31
R&S® ZV-WR05 (without Sliding Match standard), stock no. 1307.8106.10
R&S® ZV-WR05 (with Sliding Match standard), stock no. 1307.8106.11
© 2010 Rohde & Schwarz GmbH & Co. KG
81671 Munich, Germany
Printed in Germany – Subject to change – Data without tolerance limits is not binding.
®
R&S is a registered trademark of Rohde & Schwarz GmbH & Co. KG.
Trade names are trademarks of the owners.
The following abbreviations are used throughout this document:
®
R&S ZV-WR02 / -WR03 / -WR05 is abbreviated as R&S ZV-WR02 / -WR03 / -WR05
R&S® ZV-WR02 / -WR03 / -WR05
Safety Instructions
Safety Instructions
The calibration kits have been designed and tested in accordance with the EC
Certificate of Conformity and have left the manufacturer’s plant in a condition fully
complying with safety standards.
CAUTION
General safety instructions
To maintain this condition and to ensure safe operation, you must
observe all instructions and warnings given on this page.
Mechanical protection
The calibration kits (especially the waveguide flanges) must be protected against
mechanical damage. Furthermore the waveguides must be shielded from dust.
While not mounted, protect the waveguide flanges by attaching the included caps. Avoid
scratching the contact surfaces of the waveguide flanges.
Mounting a standard
The waveguide flanges of the standards are high-precision mechanical components that
can be damaged by improper handling, e.g. by canting the flanges. Use a flat, stable
surface for your test setup and align the flanges accurately before mounting.
Opening the standards
Do not disassemble the standards. This applies especially to the sliding match standard
consisting of several mounted parts. The standards can be repaired only at the
manufacturer's service department.
Avoid heavy shocks
Heavy shocks can damage internal parts of the standards. Shock-proof packing should
therefore be used for storing and dispatching of the calibration kits. Use the wooden box
for this purpose.
Damage caused by cleaning agents
Cleaning agents contain substances that may damage the standards, e.g. solventcontaining cleaning agents may damage the labeling. Never use cleaning agents such
as solvents (thinners, acetone etc.), acids, bases or other substances. Protect the
waveguides from any liquids.
The outside of the standards is suitably cleaned using a soft, line-free dust cloth.
Damage level
The damage level of the calibration kits is listed in the data sheet. Exceeding this level
may damage the calibration standards.
Technical Information 1307.7274.92 – 03
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R&S® ZV-WR02 / -WR03 / -WR05
Waveguide Calibration Kits
Waveguide Calibration Kits
The waveguide calibration kits R&S ZV-WR02 / -WR03 / -WR05 allow you to calibrate
network analyzers for test setups involving frequency converters. The calibration kit
R&S ZV-WR02 is suited for R&S ZVA-Z500 converters, R&S ZV-WR03 is suited for
R&S ZVA-Z325 converters, R&S ZV-WR05 is suited for R&S ZVA-Z220 converters.
The calibration kits contain the following standards:
A Short standard which also serves as a Reflect standard
A (Fixed) Match standard
Two Shims, each containing a short transmission line. The length difference of the
shims (see data sheet) corresponds to a quarter wavelength ( /4) at the center
frequency of the converter’s operating ranges and a 180 deg phase shift of the
reflection coefficients.
A Sliding Match standard (kits 1307.7300.31 and 1307.8106.11), providing more
accurate results than the Fixed Match standard – at higher test effort.
Technical Information 1307.7274.92 – 03
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R&S® ZV-WR02 / -WR03 / -WR05
Sliding Match Standard
The following table provides an overview of the available standards for rectangular
waveguide calibration and the technical implementation using the calibration kits.
Standard Type
Technical Implementation
Open
Not available in waveguide technology, replaced by "Offset Short"
Short
Short + Shim #1, both contained in the calibration kit
Offset Short
Short + Shim #2, both contained in the calibration kit
(Fixed) Match
Contained in the calibration kit
Sliding Match
Contained in the calibration kits 1307.7300.31 and 1307.8106.11
Reflect
Short, contained in the calibration kit
Through
Through connection of the two waveguide flanges with Shim #1 in-between
Line 1
Through connection of the two waveguide flanges with Shim #2 in-between.
In view of the bandwidth of the frequency converters, Line 2 is not needed.
Attenuation
Not contained in the calibration kit
Symmetrical
Network
Not contained in the calibration kit
The standards in the calibration kit allow all one-port and two-port calibration types
supported by the network analyzer except TNA.
The characteristic data of the standards varies very little from one calibration kit to
another. Hence there is no need to load cal kit data for each individual kit. The data is
already stored in the network analyzer (software option R&S ZVA-K8 and firmware
versions V2.45 (R&S ZV-WR03) / V2.72 (R&S ZV-WR05) / V2.75 (R&S ZV-WR02) or
higher are required).
It is possible to export the stored data to a file. Use the "Cal-Kits" dialog of the network
analyzer for this purpose: "Channel" > "Calibration" > "Cal-Kits" > "Export Kit ...".
Sliding Match Standard
The sliding match standard is part of the calibration kits 1307.7300.31 and
1307.8106.11. It is a one-port standard consisting of a precision waveguide section with
a movable, low-reflection load element (sliding load). This standard is used because no
perfect match is available. However, a series of measurements at a given frequency
with equal mismatch and varying phase yields reflection factors that are located on a
circle in the Smith chart. The center of this circle corresponds to perfect match. The
network analyzer determines the center point and applies further corrections following
I. Kása's circle-fitting algorithm.
Technical Information 1307.7274.92 – 03
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R&S® ZV-WR02 / -WR03 / -WR05
Performing a System Error Correction
To obtain the reflection coefficient for a perfectly matched calibration standard, the
sliding load must be measured at least at three positions which should be unequally
spaced to avoid overlapping data points. Increasing the number of positions to 4 – 6 can
improve the accuracy. It is recommended to use the positions listed below. They are
optimized for the frequency ranges of the calibration kits. Set the adjustable screw of the
standard to the following positions:
R&S ZV-WR03 (220 GHz to 325 GHz):
0 mm, 0.12 mm, 0.27 mm, 0.48 mm, 0.71 mm, 1.42 mm
R&S ZV-WR05 (140 GHz to 220 GHz):
0 mm, 0.18 mm, 0.41 mm, 0.72 mm, 1.07 mm, 2.15 mm
If you accidentally unscrew the knob completely, simply screw it on again.
Performing a System Error Correction
Notes:
Thermal fluctuations cause linear expansion of the waveguide components and
result in phase drift. An environment with a stable temperature within the range
stated in the data sheet is a prerequisite for accurate measurements.
A power calibration must be performed previous to system error correction. Refer to
the documentation of your frequency converter for instructions.
If you readjust the output power of the frequency converter (using the knurled knob
at the top of the converter) an already performed system error correction is no longer
valid. For that reason adjust the output power of the frequency converter before
system error correction.
TRL Calibration
The following example reports a TRL calibration for a four port R&S ZVA analyzer which
is connected to two frequency converters. The test setup is described in the R&S ZVAZ325 manual. It is suitable for transmission and reflection measurements on two-port
waveguide DUTs in the frequency range of the converters.
The calibration procedure using the analyzer’s “Calibration Wizard” is straightforward
(for details refer to the analyzer help system, section “Guided Calibration”):
1. Activate the Frequency Converter Mode (“System” > “System Config…” >
“Frequency Converter”) and connect the two converters.
2. Click “Channel” > “Start Cal” > “Two Port P1 P2” > “TRL”.
The calibration kit R&S ZV-WR03 is preinstalled. It is displayed in the “Select Physical
VNA Test Port Connector(s)” dialog, together with the appropriate connector type.
Technical Information 1307.7274.92 – 03
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R&S® ZV-WR02 / -WR03 / -WR05
Performing a System Error Correction
Connector type and calibration kit selection
3. Click “Next” to proceed to the “Measure Standards” dialog.
Technical Information 1307.7274.92 – 03
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R&S® ZV-WR02 / -WR03 / -WR05
Performing a System Error Correction
4. Connect the Short standard from the calibration kit to the frequency converter no. 1
(the converter with RF IN connected to the analyzer port no. 1) and click “Port 1:
WR03” > “Reflect” to initiate the calibration sweep.
5. Proceed in a similar way, using the Short at Port 2.
6. Establish the through connection using the Shim #1 between the ports.
7. Establish the line connection using the Shim #2 between the ports.
8. Click “Apply” to calculate and apply the system error correction data and close the
wizard.
Tips:
With calibration techniques involving a match standard (M) you can use the sliding
match instead of the fixed match in order to improve the accuracy of the system error
correction; see section Sliding Match Standard on page 5. Both standards cover the
same frequency range.
You can check the calibration by measuring a standard that was not used during the
system error correction (e.g. the fixed match to check a TRL calibration). Note that this
check is incomplete (e.g. the transmission is not verified when using a one-port standard
like a fixed match).
UOSM Calibration
UOSM calibration uses an unknown through1 and yields two solutions related to
different transmission phase values. The two solutions differ by 180 deg – only one
solution is valid.
Within a coaxial system the analyzer selects the correct solution automatically. This is
not possible in a waveguide system because the delay time is frequency-dependent
(dispersive propagation). The valid solution has to be selected manually. For this
purpose the following dialog opens during calculation of the system error correction data
(see step 8 above):
Check “Dispersive” and select the right solution from the "Phase" drop-down list.
1
Any two-port network whose S-parameters fulfill the reciprocity condition S21 = S12 can be used as an
unknown through (e.g. a waveguide bend).
Technical Information 1307.7274.92 – 03
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