A Network Analyzer For Active Components

Transcription

2 Outline Review of S-parameters Theory of Large-Signal Network Analysis The Large-Signal Network Analyzer The Calibration Active Component Characterization under CW stimulus under modulation stimulus in non-50 Ohm environment Modeling Model verification Measurement-based behavioral model Conclusions Copyright 2005 NMDG Engineering 2

3 Definition of S-parameters As function of frequency f 0 a 1 b 1 a 2 b 2 b b 1 2 ( ( f f 0 0 ) = S ) = S ( ( f f 0 0 ) ) a 1 a 1 ( ( f f 0 ) + S 0 ) + S ( ( f 0 f 0 ) ) a 2 a 2 ( ( f 0 f 0 ) ) S-parameters are a behavioral model S-parameters describe completely the linear behavior S-parameters cannot be determined properly with one measurement Copyright 2005 NMDG Engineering 3

4 Measuring S-parameters 50Ω f 0 50Ω f 0 Measurement System Measurement System a 1 b 1 Transistor RFIC System a 2 b 2 Experiment 1 Superposition a 1 b 1 Transistor RFIC System a 2 b 2 Experiment 2 a1 i, b1 i, a2i, b2i with i representing different experiments Analysis b b 1 2 = = S S a 1 a 1 + S + S a 2 a 2 f 0 Copyright 2005 NMDG Engineering 4

5 Example: Packaged FET Commercial available FET in fixture Test Port 1 Test Port 2 f 0 Bias Control f 0 : 1GHz - 18 GHz, step = 100 MHz Calibration Short Open Load Thru V gs = -0.3 V V ds = 1.5 V Copyright 2005 NMDG Engineering 5

9 Nonlinear Behavior - Harmonic Generation 2 GHz Increasing Power Test Port 1 Test Port 2 a 1 a1 = 20 dbm a1 = 0 dbm b 2 Generation of Harmonics Noise Floor b2 2 b Superposition Copyright 2005 NMDG Engineering 9

10 Nonlinear Behavior - Intermodulation Generation Vector Signal Z Generator 0 2-tone, carrier 2 GHz Vector Signal Analyzer Generation of Intermods a 1 What happens at the input? Vector Signal Analyzer Display What is the meaning of this measurement? Copyright 2005 NMDG Engineering 10

11 Complete Characterization of Active Components Measurement System Realistic Stimulus Realistic Stimulus v 1 i 1 a 1 b 1 Transistor RFIC System a 2 b 2 v 2 i 2 Representation Domain Physical Quantity Sets Frequency (f) Travelling Waves (A, B) Time (t) Voltage/Current (V, I) Freq - time (envelope) Characterization Copyright 2005 NMDG Engineering 11

12 Small-Signal Network Analysis: S-parameters 50Ω f 0 50Ω f 0 Measurement System Measurement System a 1 b 1 Transistor RFIC System a 2 b 2 Experiment 1 Superposition a 1 b 1 Transistor RFIC System a 2 b 2 Experiment 2 a1 i, b1 i, a2i, b2i with i representing different experiments Analysis b b 1 2 = = S S a 1 a 1 + S + S a 2 a 2 f 0 Copyright 2005 NMDG Engineering 12

13 Large-Signal Network Analysis Measurement System Realistic Stimulus Realistic Stimulus v 1 i 1 a 1 b 1 Transistor RFIC System a 2 b 2 v 2 i 2 Different Experiments a1 i, b1 i, a2i, b2i with i representing different experiments Analysis f ( v g( v 1 1, v, v 2 2, i, i 1 1, i, i 2 2, t, t f ) = 0 f ) = 0 Copyright 2005 NMDG Engineering 13

14 Large-Signal Network Analysis in a nutshell Measurement System Realistic Stimulus Realistic Stimulus v 1 i 1 a 1 b 1 Transistor RFIC System a 2 b 2 v 2 i 2 Representation Domain Frequency (f) Time (t) Freq - time (envelope) Physical Quantity Sets Travelling Waves (A, B) Voltage/Current (V, I) Analysis f ( v g( v 1 1, v, v 2 2, i, i 1 1, i, i 2 2, t, t f ) = 0 f ) = 0 Characterization Copyright 2005 NMDG Engineering 14

16 8753D 30 KHz-3GHz NETWORK ANALYZER ACTIVE CHANNEL CH 1 CH 2 RESPONSE SCALE MEAS FORMAT REF DISPLAY AVG CAL MKR START CENTER STIMULUS MENU MKR FCTN STOP SPAN ENTRY ENTRY 0. - x1 OFF INSTRUMENT STATE R CHANNEL SYSTEM US ER IN LOCAL PRESET S AVE COPY RECALL SEQ R L T S OUT HP-IB STATUS PROBE POWER FUSED PORT 1 PORT 2 TRANS FWD REFL FWD TRANS REV REFL REV +26 dbm RF 30 VDC MAX PORTS 1&2 AVOID STATIC M k n µ m Vector Network Analyzer Response Acquisition H Stimulus Calibration Reference Planes 50 Ohm S-parameters Analysis Copyright 2005 NMDG Engineering 16

17 Large-Signal Network Analyzer Response Stimulus Acquisition Modulation Source Calibration Reference Planes 50 Ohm or tuner Complete Spectrum Waveforms Harmonics and Periodic Modulation Copyright 2005 NMDG Engineering 17

18 Acquisition in LSNA Sampling Converter Filter Filter Filter Filter PC Acquisition Unit LO Capturing broadband HF signals (harmonics and modulation) using low-frequency data - acquisition requires samplers Copyright 2005 NMDG Engineering 18

19 Representation Domain: Continuos Wave Signal All voltages and currents or waves are represented by a fundamental and harmonics (including DC) X 1 X 0 X 4 X 2 X3 Freq. (GHz) Freq. (GHz) Z 1 DC DC DUT Z 2 Freq. (GHz) DC Complex Fourier coefficients X h of waveforms Freq. (GHz) Freq. (GHz) DC DC Copyright 2005 NMDG Engineering 19

20 Representation Domain: Amplitude and Phase Modulation of Continuos Wave Signal Phase Amplitude Phasor X 0 (t) X 1 (t) X 2 (t) X 4 (t) Freq. (GHz) Freq. (GHz) Modulation time DC time DC X 3 (t) Slow change (MHz) Fast change (GHz) Z 1 DUT Z 2 Freq. (GHz) time DC Complex Fourier coefficients X h (t) of waveforms Freq. (GHz) Freq. (GHz) time DC time DC Copyright 2005 NMDG Engineering 20

21 Representation Domain: Periodic Modulated Signals Amplitude Phase X 1i Phasor X 0i X 2i X 3i Periodic Modulation Z 1 DC Freq. (GHz) DC Freq. (GHz) DUT Z 2 Freq. (GHz) DC Complex Fourier coefficients X hm of waveforms DC Freq. (GHz) DC Freq. (GHz) With proper processing the class of signal is extendable to any type of multi-tone signal Copyright 2005 NMDG Engineering 21

22 Practical Limitations of LSNA Large-Signal Network analysis will be performed using periodic stimuli one - tone and harmonics periodic modulation and harmonics other types of multi - tones are possible The devices under test maintain periodicity in their response Copyright 2005 NMDG Engineering 22

24 LSNA Calibration F 0 =1GHz Stimulus Response DUT a 1 m a 1 m b 1 m a 2 Acquisition DUT a 2 m b 2 Modulation Source DUT b 1 Calibration DUT b 2 Reference Planes 50 Ohm or tuner DUT a 1 DUT b1 DUT a 2 DUT b2 Actual waves at DUT Linear Relationship a b a b m 1 m 1 m 2 m 2 Measured waves Regular VNA Calibration Power Calibration (power meter) Phase Calibration (pulse gen) Copyright 2005 NMDG Engineering 24

25 Measurement Traceability Relative Cal Phase Cal Power Cal Agilent Nose-to-Nose Standard (*) EOS (NIST) (demonstrated already with NIST) National Standards (*) Licensed to Maury and NMDG Copyright 2005 NMDG Engineering 25

28 Active HF Component Characterization Requirements DC IV Characterization MT4463A/B Modulation Characterization Small-Signal Large-Signal Adding DC Capability Accurate Complete Adding Modulation Capability Active Tuning Passive Tuning Adding Pre-match Tuner Second Source Under different Impedance Conditions Adding Tuners Copyright 2005 NMDG Engineering 28

29 Example: Packaged FET One connection Complete Characterization Commercial available FET in fixture Test Port 1 Test Port 2 f 0 Frequency Grid: f 0 = 2GHz, 9 harmonics Resolution BW: 1000 Hz Absolute Calibration using SOLT Bias Control Deembedding V gs = -0.3 V V ds = 1.5 V Copyright 2005 NMDG Engineering 29

43 Component Characterization with Passive Tuners DUT Calibration Planes Error-coefficients depend on tuner position Tuner De-embedding Tuner Control + Automatic Correction (Probe(s) and carriage) Copyright 2005 NMDG Engineering 43

44 Input and Load Impedance under CW Input Impedance of component f 0 Load provided to component Input Impedance of component f 0 Load provided to component Short Terminated 50 Ohm Terminated Tuning Input Impedance of component 2 f 0 Load provided to component Copyright 2005 NMDG Engineering 44

46 Input and Load Impedance under CW Input Impedance of component f 0 Load provided to component Input Impedance of component f 0 Load provided to component Towards Open Terminated Short Terminated Tuning Input Impedance of component 3 f 0 Load provided to component Copyright 2005 NMDG Engineering 46

49 Real-Time Component Characterization - Setup Circulator Synthesis of Load Impedances at f 0 Manual Tuner 2f 0 (optional) Vector Signal Generator i 1 i 2 Triplexer DUT f 0 v 1 v 2 f 0 3f 0 (optional) Offset + smart signal to scan amplitude and phase Copyright 2005 NMDG Engineering 49

52 Transistor Model Verification in ADS Measured a 1, including fundamendal and harmonics Model to Certify Measured a 2, including fundamendal and harmonics The model is brought into the same state as the real component The simulated response should be equal to the measured response for a good model The comparison is done at the essential data, common to both: Voltage and Currents Copyright 2005 NMDG Engineering 52

54 Measurement-based Behavioral Modeling b b 1 2 ( ( f f 0 0 ) = ) = f g ( a1( f0), a2( f0) ) ( a ( f ), a ( f )) Valid for Range of a1 Closed area on Smith Chart at output Model Prediction Measurement Copyright 2005 NMDG Engineering 54

57 Conclusion A Network Analyzer for active component characterization has been presented It measures the essential information (voltage and currents at component ports) to characterize the nonlinear behavior accurately and completely in a unified way from transistor to system under realistic conditions The Network Analyzer is ideal to study the behavior from small-signal to large-signal with one connection using simple and complex signals The Network Analyzer is ideal to certify models The Network Analyzer is ideal to create behavioral models Technical information Sales information Copyright 2005 NMDG Engineering 57