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Network Analyzers From Small Signal To Large Signal Measurements

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.

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Network Analyzers From Small Signal To Large Signal Measurements

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  1. Network AnalyzersFrom Small SignalTo Large Signal Measurements Doug Rytting

  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

  3. Network Analyzer Block Diagram

  4. Improvements with Correction

  5. Improvements with Correction

  6. Calibration Examples – 8 Term Model

  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

  8. Power Sweep - Compression Saturated output power Output Power (dBm) Compression region Linear region (slope = small-signal gain) Input Power (dBm)

  9. CH1 S21 1og MAG 1 dB/ REF 32 dB 30.991 dB 12.3 dBm C2 0 0 IF BW 3 kHz SWP 420 msec START -10 dBm CW 902.7 MHz STOP 15 dBm Power Sweep -Gain Compression • 1 dB compression: input power resulting in 1 dB drop in gain • Ratioed measurement • Output power available (non-ratioed measurement)

  10. Log Mag 1.0 dB/ Ref 21.50 dB 1:Transmission Ref -115.7 deg 2:Transmission /M Phase 5.0 deg/ 1 2 1 Power Sweep - AM to PM Conversion Ch1:Mkr1 -4.50 dBm 20.48 dB Ch2:Mkr2 1.00 dB 0.86 deg • Use transmission setup with a power sweep • Display phase of S21 • AM - PM = 0.86 deg/dB 2 Start -10.00 dBm CW 900.000 MHz Stop 0.00 dBm 1 Start -10.00 dBm Stop 0.00 dBm CW 900.000 MHz

  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

  12. b a a b 0 0 3 3 a b High Power Load 1 2 Osc a b 2 High Power Osc 1 Hot S22 Measurement System Small signal S-parameters of a nonlinear device in the presence of a high power drive signal Df away from test frequency. High Power Combine DUT [A]

  13. G A b a a b 0 0 3 3 DUT [A] a b 1 2 G OSC B a b 2 1 Hot S22 Measurement System S-parameters of a nonlinear device at a defined input or output power.

  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

  15. Pmax -1 dB S dB -2 22 dB -3 Low power High power Constant output power contours versus output load impedance Load Pull Measurement Need to measure nonlinear device behavior under actual operating conditions Parameter changes vesus output power level

  16. Load Pull System INPUT IMPEDANCE AND POWER MEASUREMENT SYSTEM OUTPUT IMPEDANCE AND POWER MEASUREMENT SYSTEM X X X X DUT INPUT TUNER OUTPUT TUNER

  17. Types of Output Tuners Harmonic load-pull Passive load-pull Active load-pull Simultaneous Drive OSC DUT

  18. LO Synthesizer HP 8360 1 - 50 GHz b a a b 2 1 2 1 T T T fo 2fo 3fo Source Synthesizer HP 8360 1 - 50 GHz T Harmonic Load Pull System Four Channel Frequency Converter HP 8510C/85110A LO Synthesizer Can be Tuned to Harmonics Port 3 Coaxial and power cals. DUT Reflectometer Mounted on Prober Input Amplifier 1 - 50 GHz TWA Port 1 Input Probe Port 2 Output Probe Port Drive PIN Switch

  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

  20. High Power Device Pulse Measurements • Control DUT Temperature • Eliminate temperature as a variable • Test high power devices on-wafer at full power • Measure devices in "unsafe" DC operating area • Test "pulsed" devices in a pulsed environment • Test environment = final application (GSM) • Pulsed radars/phased array antennas/high power MMIC's • Improve device characterization data • Model power FET's at full power level • Measure IV curves without temperature effects • Investigate trapping effects in GaAs

  21. Gate/Base T1 Drain/Collector T2 RF RF PW DC Safe Operating Limit I D Q2 Q1 V D Pulse System Capabilities • Synchronization of pulses • IV plane characterization • Point in pulse vs Frequency or Pulse profile vs Time

  22. T T Pulsed-RF Test Set T T T T Pulsed Bias/RF Meas System RF Synthesizer Measurement Controller LO Synthesizer Network Analyzer Bias Network Drain / Collector Bias Pulser Gate / Base Bias Pulser DC Power Supply Digital Multimeter Trigger Pulse Generator

  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

  24. Response Acquisition (LSNA) Stimulus 50 Ohm or Tuner ESG Large Signal Network Analyzer Complete Spectrum Waveforms Harmonics and Modulation

  25. Large Signal Network Analyzer • Measuresmagnitude 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 vectornetwork analyzer, sampling scope, spectrum analyzer and power meter.

  26. LSNA System Block Diagram Sampler Front End Requires high BW IF Requires Harmonic LO

  27. LP fLO=19.98 MHz = (1GHz-1MHz)/50 RF 50 fLO 100 fLO 150 fLO 1 2 3 Freq. (GHz) IF IF Bandwidth: 4 MHz 3 2 1 Freq. (MHz) Sampling Converter Fundamentals

  28. LSNA System Block Diagram Mixer Front End Requires harmonic sync Can use high BW IF for modulation Or low BW IF if no modulation

  29. Response Acquisition Stimulus 50 Ohm or Tuner Modulation Source Actual waves at DUT Measured waves 7 relative error terms same as a VNA Absolute magnitude and phase error term Nonlinear Calibration - Model

  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.

  31. Example # 1 • Complete device measurement capability using a Large Signal Network Analyzer (LSNA).

  32. -0.2 V -1.2 V Open port 50 Ohm load Device Measurement

  33. Example # 2 • Device measurement verification and measurement-based model improvement.

  34. Parameter Boundaries GaAs pseudomorphic HEMT gate l=0.2 um w=100 um MODEL TO BE OPTIMIZED “Chalmers Model” generators apply LSNA measured waveforms “Power swept measurements under mismatched conditions” Model Verification & Improvement

  35. During OPTIMIZATION Voltage - Current State Space voltage current gate drain gate drain Time domain waveforms Frequency domain Model Verification & Improvement

  36. After OPTIMIZATION Voltage - Current State Space voltage current gate drain gate drain Time domain waveforms Frequency domain Model Verification & Improvement

  37. Vector Network Analyzer References

  38. Large Signal Network Analyzer References

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