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Network Analyzers From Small Signal To Large Signal Measurements. Doug Rytting. Agenda. Small Signal Measurements & Error Correction Compression and AM to PM Hot S22 Measurements Load Pull Measurements Pulse Measurements Large Signal Network Analyzer Measurements. - PowerPoint PPT Presentation
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Slide 1
Network AnalyzersFrom Small Signal
To Large Signal Measurements
Doug Rytting
Slide 2
Agenda
Small Signal Measurements & Error Correction
Compression and AM to PM
Hot S22 Measurements
Load Pull Measurements
Pulse Measurements
Large Signal Network Analyzer Measurements
Slide 3
RFSource
LOSource
a0
b0 b3
Port - 1 Port - 2
a3
DUTa2
a1
b1
b2Cable Cable
IF
IF
IF
IF
Network Analyzer Block Diagram
Slide 4
ERRORS REMOVED ERRORS REMAINING
Noise and Residuals
Receiver Linearity
Drift after Error-Correction
Stability after Error-Correction
Repeatability of Connectors, etc
Lower Lever Leakage Paths
Errors of Calibration Standards
Port Match
Directivity
Tracking
Main Leakage Paths
Improvements with Correction
Slide 5
Improvements with Correction
Slide 6
TRL & LRL
TRM & LRM
TraditionalTOSL
(Overdetermined)
LRRM
UXYZUnknown Thru
TXYZ & LXYZ
Thru (T) or Line (L) withknown S-parameters
[4 conditions]
Unknown Line (U) withS 12 = S 21
[1 condition]
Line (L) with knownS 11 and S 22
[2 conditions]
Known Match (M)on port-1 and port-2
[2 conditions]
3 known Reflects (XYZ)on port-1 or port-2
[3 conditions]
3 known Reflects (OSL)on port-1
[3 conditions]
Known match (M)on port-1
[1 condition]
3 known Reflects (XYZ)on port-1
[3 conditions]
2 unknown equal Reflects(RR) on port-1 and port-2
[2 conditions]
3 known Reflect (OSL)on port-2
[3 condition]
Unknown equal Reflect (R)on port-1 and port-2
[1 condition]
Seven or more independent known conditions must be measuredA known impedance (Z 0) and a port-1 to port-2 connection are required
Line (L) with knownS-parameters[4 conditions]
Thru (T) or Line (L) withknown S-parameters
[4 conditions]
Thru (T) or Line (L) withknown S-parameters
[4 conditions]
Thru (T) withknown S-parameters
[4 conditions]
Unknown equal Reflect (R)on port-1 and port-2
[1 condition]
3 known Reflects (XYZ)on port-2
[3 conditions]
Calibration Examples – 8 Term Model
Slide 7
Agenda
Small Signal Measurements & Error Correction
Compression and AM to PM
Hot S22 Measurements
Load Pull Measurements
Pulse Measurements
Large Signal Network Analyzer Measurements
Slide 8
Saturated output power
Outp
ut
Pow
er
(dB
m)
Input Power (dBm)
Compression region
Linear region (slope = small-signal gain)
Power Sweep - Compression
Slide 9
0
CH1 S21 1og MAG 1 dB/ REF 32 dB 30.991 dB 12.3 dBmC2
IF BW 3 kHz SWP 420 msecSTART 10 dBm CW 902.7 MHz STOP 15 dBm
0
1 dB compression: input power resulting in 1 dB drop in gain
Ratioed measurement Output power available (non-
ratioed measurement)
Power Sweep -Gain Compression
Slide 10
1:Transmission Log Mag 1.0 dB/ Ref 21.50 dB
Use transmission setup with a power sweep Display phase of S21 AM - PM = 0.86 deg/dB
Start -10.00 dBm Stop 0.00 dBmCW 900.000 MHzStart -10.00 dBm Stop 0.00 dBmCW 900.000 MHz
2:Transmission /M Phase 5.0 deg/ Ref -115.7 deg
1
2
1
1
2
Ch1:Mkr1 -4.50 dBm 20.48 dB
Ch2:Mkr2 1.00 dB 0.86 deg
Power Sweep - AM to PM Conversion
Slide 11
Agenda
Small Signal Measurements & Error Correction
Compression and AM to PM
Hot S22 Measurements
Load Pull Measurements
Pulse Measurements
Large Signal Network Analyzer Measurements
Slide 12
Hot S22 Measurement System
Small signal S-parameters of a nonlinear device in the presence of a high power drive signal f away from test frequency.
Osc
b 1
a 1 b 2
a 2
a3
b3
a b0 0
DUT[A]
High Power Load
High Power
Osc
High Power
Combine
Slide 13
Hot S22 Measurement System
S-parameters of a nonlinear device at a defined input or output power.
OSCb 1
a 1 b 2
a 2
a3
b3
a b0 0
DUT[A]
A
B
Slide 14
Agenda
Small Signal Measurements & Error Correction
Compression and AM to PM
Hot S22 Measurements
Load Pull Measurements
Pulse Measurements
Large Signal Network Analyzer Measurements
Slide 15
Need to measure nonlinear device behavior under actual operating conditions
Low power
High power
S 22
Constant output power contours versusoutput load impedance
Pmax
-1 dB
-2 dB
-3 dB
Parameter changes vesusoutput power level
Load Pull Measurement
Slide 16
DUTX XX X
INPUTIMPEDANCE
ANDPOWER
MEASUREMENTSYSTEM
OUTPUTIMPEDANCE
ANDPOWER
MEASUREMENTSYSTEM
INPUTTUNER
OUTPUTTUNER
Load Pull System
Slide 17
Harmonic load-pullPassive load-pull Active load-pull
Simultaneous Drive
OSC
DUT
Types of Output Tuners
Slide 18
Harmonic Load Pull System
DUT
Four Channel Frequency ConverterHP 8510C/85110A
b 2a 1 a 2b 1
LO SynthesizerHP 8360
1 - 50 GHz
Port 1InputProbe
Port 2Output Probe
ReflectometerMounted on
Prober
T
T
Tfo 2fo 3fo
T
Source SynthesizerHP 8360
1 - 50 GHz
Port DrivePIN Switch
Input Amplifier 1 - 50 GHz TWA
Port 3Coaxial andpower cals.
LO SynthesizerCan be Tunedto Harmonics
Slide 19
Agenda
Small Signal Measurements & Error Correction
Compression and AM to PM
Hot S22 Measurements
Load Pull Measurements
Pulse Measurements
Large Signal Network Analyzer Measurements
Slide 20
High Power Device Pulse Measurements
Control DUT TemperatureEliminate temperature as a variableTest high power devices on-wafer at full power Measure devices in "unsafe" DC operating area
Test "pulsed" devices in a pulsed environmentTest environment = final application (GSM) Pulsed radars/phased array antennas/high power MMIC's
Improve device characterization dataModel power FET's at full power levelMeasure IV curves without temperature effectsInvestigate trapping effects in GaAs
Slide 21
Pulse System Capabilities
Synchronization of pulses
IV plane characterization
Point in pulse vs Frequency or Pulse profile vs Time
Gate/Base
Drain/Collector
RF
RF PW
T1
T2
ID
VD
Q1
Q2
DC Safe Operating Limit
Slide 22
Pulsed Bias/RF Meas System
Network Analyzer MeasurementController
Drain / CollectorBias Pulser
Gate / BaseBias Pulser
DC Power Supply
Pulse Generator
Digital Multimeter
Pulsed-RFTest Set
RF Synthesizer
LO Synthesizer
Bias Network
T
Trigger
T
T
T
T
T
Slide 23
Agenda
Small Signal Measurements & Error Correction
Compression and AM to PM
Hot S22 Measurements
Load Pull Measurements
Pulse Measurements
Large Signal Network Analyzer Measurements
Slide 24
Complete SpectrumWaveforms
Harmonics and Modulation
Large Signal Network Analyzer
Acquisition (LSNA)
Stimulus
Response
ESG 50 Ohmor
Tuner
Slide 25
Large Signal Network Analyzer
Measures magnitude and phase of incident and reflected waves at fundamental, harmonic, and modulation frequencies.Calibrated for relative and absolute measurements for both linear and nonlinear components at the device under test.Calculate calibrated voltage and current in both the time and frequency domains.
Combination of a vector network analyzer, sampling scope, spectrum analyzer and power meter.
Slide 26
LSNA System Block DiagramSampler Front End
Requires high BW IFRequires Harmonic LO
Slide 27
Sampling Converter Fundamentals
LP
Freq. (GHz)1 2 3
50 fLO 100 fLO 150 fLO
Freq. (MHz)1 2 3
RF
IF
fLO=19.98 MHz = (1GHz-1MHz)/50
IF Bandwidth: 4 MHz
Slide 28
LSNA System Block DiagramMixer Front End
Requires harmonic syncCan use high BW IF for modulationOr low BW IF if no modulation
Slide 29
Nonlinear Calibration - Model
Measured wavesActual waves at DUT
7 relative error termssame as a VNAAbsolute magnitude
and phase error term
50 Ohmor
Tuner
AcquisitionStimulus
Response
ModulationSource
0a 0b 3a 3b
1a 2a
1b 2b
Slide 30
Nonlinear Calibration
Relative calibration at the fundamental and harmonic frequencies determines the 7 normal error terms.
Power calibration at the fundamental and harmonic frequencies determines the magnitude of K.
Phase reference generator calibration determines the phase of K relative to the fundamental frequency.
Reference generator is an impulse that must be accurately modeled or measured.
Slide 31
Example # 1
Complete device measurement capability using a Large Signal Network Analyzer (LSNA).
Slide 32
Device Measurement
)(1 ta )(1 tb
)(2 ta )(2 tb
)(1 tv
)(1 ti
)(2 tv
)(2 ti dsv
dsi
-1.2 V
-0.2 V
MHzf 9000
50 Ohm loadOpen port
gv
Slide 33
Example # 2
Device measurement verification and measurement-based model improvement.
Slide 34
MODEL TO BE OPTIMIZED
generators apply LSNA measured waveforms
“Chalmers Model”
“Power swept measurements under mismatched conditions”
GaAs pseudomorphic HEMTgate l=0.2 um w=100 um
Parameter Boundaries
Model Verification & Improvement
Slide 35
During OPTIMIZATION
Time domain waveforms Frequency domaingate drain
voltage
current
gate drain
Voltage - Current State Space
Model Verification & Improvement
Slide 36
Model Verification & Improvement
Time domain waveforms Frequency domaingate drain
voltage
current
gate drain
Voltage - Current State Space
After OPTIMIZATION
Slide 37
Vector Network AnalyzerReferences
Slide 38
Large Signal Network Analyzer References