Configuration of PNA-X, NVNA and X parameters

Configuration of PNA-X, NVNA and X parameters
Configuration of PNA-X, NVNA and X parameters
VNA
1. S-Parameter
Measurements
2. Harmonic
Measurements
NVNA
3. X-Parameter
Measurements
Introducing the PNA-X
50 GHz
43.5 GHz
26.5 GHz
13.5 GHz
PNA-X
Agilent’s Premier
Performance Network
Analyzer For Active
Device Test
Industry-Leading Performance
N5242A PNA-X Performance
Frequency Range
10 MHz to 26.5 GHz
IF Bandwidths
1 Hz to 5 MHz
System Dynamic Range
132 dB
Receiver Dynamic Range
130 dB
Trace Noise (1 kHz IF BW)
<0.0006 dB
Output Power
+16 dBm
Source Harmonics
-60 dBc
0.1 dB Receiver Compression
+13 dBm
Power Sweep Range (ALC)
40 dB
Product Features – Signal Sources
Second internal source
• Two-tone tests: intermodulation, X-param, … and more
Source 1
• About 30x faster than PNA/PSG combination
OUT 2
OUT 1
Source improvements
• Upper frequency (26.5 GHz)
• High port power (~ +16 dBm)
• Low harmonics (> -60 dBc)
Source 2
OUT 1
– Improves accuracy for amplifier and converter tests
– Eliminates or reduces need for external filters
• Wide ALC range (40 dB)
– Easily sweep power from linear to compression region
– Increased flexibility for optimizing power for two-source tests
OUT 2
Product Features – Receivers
Outstanding receiver compression (0.1 dB comp: +12 dBm)
• Improves dynamic linearity when measuring amplifiers
• Improves gain-compression accuracy
PNA-X
PNA-X receiver linearity: Most accurate receiver in
the world!
+-0.01 dB over 80 dB
Product Features – Test Set
Flexible signal routing
• Internal signal combiner
– Use for IMD, Hot S22, X-param, phase vs drive measurements
– Easily switch between one and two source measurements
• Front panel jumpers to access couplers and receivers
– Add high-power components for power amplifier measurements
– Add reference mixer for mixer/converter measurements
• Rear-panel signal routing with mechanical switches
– Add signal-conditioning hardware like filters, amplifiers
– Add other test equipment to extend suite of measurements
4-Port 26.5 GHz PNA-X Options 419, 423
rear panel
J11
J10
J9
J8
J7
J4
OUT 1
OUT 1
J2
J1
LO
Source 2
Source 1
J3
OUT 2
OUT 2
To receivers
R3
R1
R4
A
C
35 dB
65 dB
Test port 3
Receivers
Mechanical switch
B
D
35 dB
65 dB
Test port 1
RF jumpers
R2
35 dB
65 dB
Test port 4
65 dB
Test port 2
35 dB
Rear Access Loops and Internal Switches
Add signal-conditioning hardware
Example 1:
Switch between normal path
and high-power path
Booster amplifier
(max output = +30 dBm)
Booster amp
LO
Source 2
To rear
access loops
To receivers
Source 1
OUT 1
OUT 1
OUT 2
OUT 2
R1
R2
B
A
Test port 1
Source 2
Output 1
DUT
DUT
Source 2
Output 2
Test port 2
Extending Test Suite With Other Instruments
Example 2:
Switch between network analyzer and
external source/analyzer combination for
ACPR testing with digital modulation
Spectrum
analyzer
Signal
generator
Network
analyzer
To rear access loops
DUT
Easy Control of External Signal Sources
Internal sources
Product Features - General
Common PNA features
•
•
•
•
Flexible channels, traces, windows
Open Windows® architecture
LAN, GPIB, USB connectivity
Built-in HELP system
Advanced calibrations
•
•
•
•
•
Unknown through, QSOLT, offset load
Data-based with weighted-least-squares
Automatic port extensions
Match-corrected mixer calibrations
ECal electronic calibration
Remote programming
• Code compatible with current PNAs
• SCPI, COM, DCOM interface
Channel
Trace
Trace
Trace
Trace
Trace
Trace
Demonstration 1/3
PNA-X performance and GUI
-
Trace Noise
-
Dynamic Range
-
Receiver Leveling
-
…
Dynamic Range and Accuracy
Error Due to Interfering Signal
100
-
10
Error (dB, deg)
Dynamic range is very
important for
measurement accuracy!
+
It depends on IFBW!!!
phase
error
1
magn error
0.1
0.01
0.001
0
-5
-10
-15
-20
-25
-30
-35
-40
-45
Interfering signal (dB)
-50
-55
-60
-65
-70
Receiver Leveling – What Is It?
rear panel
J11
J10
J9
J8
J7
J2
• A new source power leveling mode
• Uses any one of receivers as a
detector
• Can use different receivers for
different source ports
• Can be used with any sweep types
• Available in Standard, GCA, IMD and
FCA measurement classes
OUT
1
Source
1
OUT
1
OUT
2
J1
L
O
Source
2
OUT
2
To
receivers
Pulse
modulator
Pulse
modulator
R1
Pulse generators
A
R2
B
1
2
3
4
Test port 1
Source 2
Output 1
Source 2
Output 2
Test port 2
Receiver Leveling – When Is It Useful?
• Corrects short term drift errors when using
external components
• Improves source accuracy at low power level
• Improves source linearity performance
• Extend minimum source power level
• Expand power sweep range up to 60 dB
• Enables power-leveled pulsed-RF
measurements
• Enables power-leveled mmW measurements
Demonstration 2/3
Amplifier Test Methodology
- Pretest:
Simple characterization to understand the measurement requirements
of the amplifier
- Setup:
Optimize the setup of the measurement to fit the needs and attributes of
the Device Under Test (DUT)
- Calibration: Understand and choose methods that improve the accuracy of the
measurements
- Measurement: Acquire the data in the most effective way
- Analysis: Apply post measurement algorithms to display the data in convenient
and effective ways
- Data Save:
use
Save the results in formats most convenient for offline analysis and
Systematic Measurement Errors
R
A
B
Crosstalk
Directivity
DUT
Frequency response
reflection tracking (A/R)
transmission tracking (B/R)
Source
Mismatch
Load
Mismatch
Six forward and six reverse error terms
yields 12 error terms for two-port devices
Types of Error Correction
response (normalization)
simple to perform
only corrects for tracking errors
thru
stores reference trace in memory,
then does data divided by memory
vector
requires more standards
requires an analyzer that can measure phase
accounts for all major sources of systematic error
–
–
–
–
–
–
SHORT
S11a
thru
OPEN
S11 m
LOAD
Adapter Considerations
reflection from
adapter
leakage signal
desired signal
ρ
measured = Directivity +
ρ
adapter +
ρ
DUT
Coupler directivity = 40 dB
Adapter
Worst-case
System Directivity
28 dB
17 dB
14 dB
DUT
Termination
DUT has SMA (f) connectors
APC-7 calibration done here
Adapting from APC-7 to SMA
(m)
APC-7 to SMA (m)
SWR:1.06
APC-7 to N (f) + N (m) to SMA (m)
SWR:1.05
SWR:1.25
APC-7 to N (m) + N (f) to SMA (f) + SMA (m) to (m)
SWR:1.05
SWR:1.25
SWR:1.15
Crosstalk: Signal Leakage Between
Test Ports During Transmission
DUT
Can be a problem with:
high-isolation devices (e.g., switch in open position)
high-dynamic range devices (some filter stopbands)
Isolation calibration
adds noise to error model (measuring near noise floor of system)
only perform if really needed (use averaging if necessary)
if crosstalk is independent of DUT match, use two terminations
if dependent on DUT match, use DUT with termination on output
LOAD
DUT
DUT
LOAD
Performing the Calibration: SOLT
Two most common types of calibration: SOLT and TRL
• Both types remove all the systematic error terms
• Type and definition of calibration standards are different
SOLT
• Basic form uses short, open, load, and known-thru standards
• Advanced forms use multiple shorts and loads, unknown thru, arbitrary
impedances (ECal)
• Uses the 12-term error model
Advantages:
• Easy to perform
• Applicable to a variety of environments
(coaxial, fixture, waveguide…)
• Provides a broadband calibration
Performing the Calibration: TRL
Basic form: thru, reflect, line standards
Advanced forms: TRM, LRM, LRM+, LRL, LRRL, LRRM…
Uses a 10-term error model
Advantages
• Uses standards that are easy to fabricate and have simpler definitions than
SOLT
–
–
–
–
Only need transmission lines and high-reflect standards
Required to know impedance and approximate electrical length of line standards
Reflect standards can be any high-reflection standards like shorts or opens
Load not required; capacitance and inductance terms not required
• Potential for most accurate calibration (depends on quality of transmission
lines)
• Commonly used for in-fixture, on-wafer and waveguide environments
Calibrating Non-Insertable Devices
When doing a through cal, normally test ports mate directly
cables can be connected directly without an adapter
result is a zero-length through
What is an insertable device?
has same type of connector, but different sex on each port
has same type of sexless connector on each port (e.g. APC7)
What is a non-insertable device?
one that cannot be inserted in place of a zero-length through
has same connectors on each port (type and sex)
has different type of connector on each port (e.g., waveguide on one
port, coaxial on the other)
DUT
Compromises of Traditional Non-Insertable Methods
Swap equal adapters
Calibration
Measurement
• Need phase matched adapters of different sexes (e.g., f-f, m-f)
• Errors introduced from loss and mismatch differences of adapters
Use characterized thru
Known S-parameters
• Two-step process (characterize thru, then use it during calibration)
• Need a non-insertable cal to measure S-parameters of characterized thru
Perform adapter removal cal
2-port cal 1
2-port cal 2
• Accurate but many steps in calibration (need to do two 2-port calibrations)
Add adapters after cal, then, during measurement…
• Use port extensions – doesn’t remove adapter mismatch effects
• De-embed adapters (S-parameters known) – similar to characterized thru
DUT
Unknown Thru Calibration
The “Unknown Thru” technique is…
Used when a “flush” (zero-length or mate-able) thru cannot be used
or when using a flush thru would cause measurement impairment
A refinement of SOLT calibration
Also called short-open-load-reciprocal-thru (SOLR)
Unknown Thru technique eliminates need for…
Matched or characterized thru adapters
Moving or bending test cables
Works great for many component measurement challenges…
Non-insertable devices
Mechanically difficult situations
Multiport devices
Order of Fixturing Operations
First, single-ended functions
are processed in this order:
•
•
•
•
•
Port extensions
2-port de-embedding
Port Z (impedance) conversion
Port matching / circuit embedding
4-port network embed/de-embed
Then, balanced functions are
processed in this order:
• Balanced conversion
• Differential- / common-mode port Z conversion
• Differential matching / circuit embedding
Example circuit simulation
Equation Editor
If You Can’t Measure it, Compute It!!
Powerful and convenient tool to add computation results
as a new trace to your measurement display.
• Equations can be based on any
combination of existing traces or
underlying channel parameters
or memory traces along with any
user defined constants.
• You can use any of the basic
operators or choose from an
extensive library of functions and
standard constants.
• Equations can be stored for later
use.
• Import your own compiled library
of functions
K-Factor, Stability
Oscillation possible when | Γin | or | Γout| > 1 (negative
resistance)
Unconditional stable when Re{Zin} & Re{Zout} for all passive Zs
& ZL
Γs Γin
Γout ΓL
ZS
ZL
Zin
Zout
K-Factor, Stability
Unconditional stable when…
K=
…and
1 - |S11|2 - |S22|2 + |∆|2
2|S12S21|
∆ = |S11S22 – S12S21| < 1
…at each frequency
All 4 S-parameters required
Use higher power for reverse measurements
>1
Demonstration 3/3
Advanced features
-
Frequency Offset
-
Spectrum view, Images!
-
Path Configuration
-
Hot S22
-
…
Example of IF shift using FOM
Wideband IF path = 7.606 MHz
Narrowband IF path = 10.7 MHz
Image signals
Real signals
Special cases for high gain devices
For high gain devices (more than 40 dB), special care in the Sparameter cal is needed to avoid noise related issues
By default, the reverse power is set to the source power
– In high gain devices the source power is very low
– Often, port 2 padding is needed to reduce power from the amplifier
– This makes the reverse measurement very noisy
– Noise in the reverse measurements show up in S11 and S21 through the
full 2-port error correction math
Follow the earlier guidelines, and set the Port 2 power higher
than the Port 1 power by just less than the gain of the amplifier
Special cases for high power devices
For devices needing higher drive power, use the “loops” on the
rear of the PNA-X to add a booster amplifier
Because this comes before the R-channel, you can use the Rchannel and Rx Leveling to compensate for amplifier drift
Maximum input power is +30 dBm to the rear panel
External padding and maybe external coupling might be
needed on port 2. Max port 2 power is +30 dBm (+43 with
option H85).
Protecting the Device: Global Power Limit
Global Power Limit sets a limit on the source port power
Power Level is referred to the port, and does not include any
external amplifiers or pads. Offsets will change the source
setting by the offset value
One set, the output power will not exceed the limit regardless of
any remote-software or front panel entries. Locking the limit will
not let front-panel users override the setting without unlocking it
from a software command
Changing power ranges after calibration
Might be necessary to evaluate a wide range of input powers
Nominal values are compensated, but fine-grain response is
not compensated for
Moving from 0 dB attenuation to any other can cause
substantial change (up to 0.5 dB)
Moving from non-zero attenuation to another non-zero is
usually better response
Changing source power (ALC power) is always OK.
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