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Large-Signal Network Analysis Technology to help the R&D Customer. Agenda. Introduction Large-Signal Network Analysis The Large-Signal Network Analyzer Calibration The core of the LSNA Technology Examples A typical LSNA measurement session Next steps in LSNA Technology Wrap-up. S.
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Large-Signal Network Analysis Technology to help the R&D Customer Page 1
Agenda • Introduction • Large-Signal Network Analysis • The Large-Signal Network Analyzer • Calibration • The core of the LSNA Technology • Examples • A typical LSNA measurement session • Next steps in LSNA Technology • Wrap-up Page 2
S I 0 Phase LO Splitter 90 Q I/Q Modulator Design Challenge “Customers are demanding more capabilities/performance from their devices.” • Designers are looking for better methods of characterizing their components Demands translate to greater design complexities • More complex modulation schemes • Higher power efficiency requirements • Improved linearity PA Designer Rx/Tx Module Matched Transistors Modeling Designer Transistors Process Engineer IC Designer PA Module Mixer MCPA System Designer Page 3
Why can’t I predict device behavior To be successful in this environment, it is essential to fully characterize and understand device behavior • Need more realistic test conditions • Devices that operate in large-signal environments can’t be characterized with linear tools Existing tools are insufficient • Network analyzers only characterize small-signals (linear) behavior accurately • Signal analyzers evaluate properties of signals interacting with the test device, they do not analyze the interactions of analyzer with the test device Page 4
AM-PM Gain Amplifier Measurements Power in and out Phase flatness ACPR Power Added Efficiency Device Under Test Loadpull Page 5
ACPR of an MCPA Build two MCPAs, one passes the other does not • Do you know what to fix? • ACPR and other measurement data only represent symptoms of the problem • No insight is provided as to the cause of the problem PASS FAIL Page 6
Z1 Z2 DUT DUT Freq. (GHz) Existing Measurements and Limitations Spectral re-growth, IMD, ACPR • Characterizes signals caused by nonlinear behavior of components - in the frequency domain EVM • Compares deviation of modulated signal from ideal - in the time domain Limitations • Characterizes signals resulting from interaction DUT - measurement system, device performance is not isolated • Results will change when environment changes • Different sources and analyzers can produce different results • Characterizing just the DUT requires perfectly matched conditions Page 7
DUT Existing Measurements and Limitations con’t AM-AM and AM-PM • Characterizes changes in output power and phase with changes in input power • Starts defining the transfer function of the nonlinear behavior Limitations • DUT performance is still not isolated from the rest of the system • Results will change with changes in the environment • Results also depend on type of test signal regardless of matched conditions Z1 Z2 DUT Freq. (GHz) Page 8
x x x x Existing Measurements and Limitations con’t VNA, SA or Pwr Mtr. VNA, SA or Pwr Mtr. Load Pull • Traditional: Characterizes applied impedances and powers at fundamental frequency • Measures incident, reflected and transmitted power as a function of S and L • Harmonic: Characterizes applied impedances and powers at fundamental and harmonics • Provides more complete information than traditional load pull. Harmonic termination has large impact on performance Limitations • Information is still missing, the DUT is not completely characterized • Does not allow to apply PA design theory (waveform engineering) • Measurements do not uniquely define a particular test state • May identify multiple local minimums as opposed to a optimal (global) minimum Load Tuner(s) (L ) Source Tuner (S ) DUT Page 9
Existing Measurements and Limitations con’t Modulated S-parameters • Attempt to use known concepts in new situations Hot S22 • Characterizes the interaction of the DUT with the load under large - signal drive • Depends on the chosen configuration Limitations • Modulated S-parameters do not have a scientific basis • Superposition principles do not apply for nonlinear behavior • Results will vary with the test conditions when device is nonlinear • Hot S22 is still missing critical information for complete nonlinear characterization • The missing data mayor may not impact measurement results Page 10
Meas Simulate Build Model ACPR = S-P Simulate Build Meas Model Power Insufficient Modeling Tools Ideal: • Measurements correlate with simulations • In a linear environment, S-Parameters are an excellent example The real world for non-linear characterization: • Insufficient models • Incomplete information • Poor correlation between measurements and simulations Page 11
Results • Cut-and-try engineering (designers “imagineer” fixes) • Design verification consumes 2/3rdsof development time • Time-to-market delays • Unpredictable design processes • Time consuming tuning and measurement requirements Page 12
How can Agilent help? • Large - Signal Network Analysis is a breakthrough new technology that provides unprecedented insight into transistor, component and system behavior using the same concepts across this complete spectrum • Through a small dedicated team Agilent is ready to work closely with early-adopter customers in different markets to create successes in their R&D environment through this technology Page 13
Agenda • Introduction • Large-Signal Network Analysis • The Large-Signal Network Analyzer • Calibration • The core of the LSNA Technology • Examples • A typical LSNA measurement session • Next steps in LSNA Technology • Wrap-up Page 14
Large - Signal Network Analyzer (LSNA) Technology • Goals • complete characterization of a device, component and system under large - signal periodic stimulus at its ports. LSNA technology is presently limited to devices that maintain periodicity in their response • deriving nonlinear component characteristics which are invariant for the used equiment and test signals • Foundation: Large-signal Network Analysis Page 15
Small-Signal Network Analysis • Small-Signal • Linear Behavior • Test signal : simple, typically a sine wave • Superposition principle to analyze behavior in realistic conditions • Network • Transistor, RFIC, Basestation Amplifier, Communication system • Analysis • Complete component characterization : S - parameters (within measurement bandwidth) Page 16
Large-Signal Network Analysis • Large-Signal • Refers to potential nonlinear behavior • Nonlinear behavior -> Superposition is not valid • Requirement: Put a DUT in realistic large-signal operating conditions • Network • Transistor, RFIC, Basestation Amplifier, Communication system • Analysis • Characterize completely and accurately the DUT behavior for a given type of stimulus • Analyze the network behavior using these measurements Page 17
Realistic Stimulus Realistic Stimulus Large-Signal Network Analysis: Overview Measurement System Transistor RFIC System • Analysis • Representation Domain • Frequency (f) • Time (t) • Freq - time (envelope) • Physical Quantity Sets • Travelling Waves (A, B) • Voltage/Current (V, I) Page 18
Practical Limitations of LSNA for Large-Signal Network Analysis • Large-Signal Network analysis will be performed using periodic stimuli • one - tone and harmonics • periodic modulation and harmonics • The devices under test maintain periodicity in their response Page 19
Continuos Wave Signal All voltages and currents or waves are represented by a fundamental and harmonics (including DC) X1 X2 X0 X4 X3 Freq. (GHz) Freq. (GHz) 1 1 2 DC 4 3 2 DC 4 3 Z1 DUT Z2 Freq. (GHz) 1 2 DC 4 3 Complex Fourier coefficients Xh of waveforms Freq. (GHz) Freq. (GHz) 1 1 2 DC 4 2 3 DC 4 3 Page 20
Amplitude and Phase Modulation of Continuos Wave Signal Phase X1(t) Amplitude X2(t) X4(t) X0(t) Phasor Freq. (GHz) Freq. (GHz) 1 1 Modulation 2 DC 4 3 2 DC 4 time 3 time X3(t) Slow change (MHz) Z1 DUT Z2 Fast change (GHz) Freq. (GHz) 1 2 DC 4 3 time Complex Fourier coefficients Xh(t) of waveforms Freq. (GHz) Freq. (GHz) 1 1 time 2 DC 4 2 3 DC 4 3 time Page 21
Periodic Modulated Signals Phase X1i Amplitude X0i X2i Phasor X3i Freq. (GHz) Freq. (GHz) 1 1 Periodic Modulation 3 2 DC 3 2 DC Z1 DUT Z2 Freq. (GHz) 1 2 DC 4 3 Complex Fourier coefficients Xhm of waveforms Freq. (GHz) Freq. (GHz) 1 1 3 2 DC 3 2 DC Page 22
Typically Waves (A, B) versus Current/Voltage (V, I) “From device to system level” Page 23
Small-Signal Network Analysis: S-parameters Measurement System Measurement System Transistor RFIC System Transistor RFIC System Experiment 2 Experiment 1 • Analysis Page 24
Realistic Stimulus Realistic Stimulus Large-Signal Network Analysis Measurement System Transistor RFIC System Different Experiments • Analysis Page 25
Agenda • Introduction • Large-Signal Network Analysis • The Large-Signal Network Analyzer • Calibration • The core of the LSNA Technology • Examples • A typical LSNA measurement session • Next steps in LSNA Technology • Wrap-up Page 26
Acquisition 50 Ohm Vector Network Analyzer Measurement Response Stimulus Calibration Reference Planes S-parameters Linear Theory Page 27
Large-Signal Network Analyzer Response Acquisition Stimulus 50 Ohm or tuner Modulation Source Calibration Reference Planes Complete Spectrum Waveforms Harmonics and Periodic Modulation Page 28
LSNA System Block Diagram Converts carrier, harmonics and modulation to IF bandwidth • RF bandwidth: 600 Mhz - 20 GHz • max RF power: 10 Watt • Modulation bandwidth • Needs periodic modulation Separates incident and reflected waves into four meas. channels Source Sampling Converter On wafer Connectorized Filter Filter PC Test Set Data-Acquisition DUT Filter Filter 10 MHz IF Cal Kit E1430 - based 4 MHz IF LO Power Std 2nd Source Phase Std Or Tuner Calibration Standards Page 29
LP Harmonic Sampling - Signal Class: CW IF Bandwidth: 4 MHz fLO=19.98 MHz = (1GHz-1MHz)/50 RF 50 fLO 100 fLO 150 fLO 1 2 3 Freq. (GHz) IF Cutt Off IF 3 2 1 Freq. (MHz) Page 30
LP Harmonic Sampling - Signal Class: Periodic Modulation fLO=19.98 MHz = (1GHz-1MHz)/50 RF 50 fLO 100 fLO 150 fLO 1 2 3 IF IF Bandwidth: 4 MHz 3 2 1 Freq. (MHz) Page 31
LP Harmonic Sampling - Signal Class: Periodic Broadband Modulation Adapted sampling process 8 MHz BW BW RF 150 fLO 1 2 3 Freq. (GHz) BW IF Freq. (MHz) BW of Periodic Broadband Modulation = 2* BW IF data acquisition Page 32
Agenda • Introduction • Large-Signal Network Analysis • The Large-Signal Network Analyzer • Calibration • The core of the LSNA Technology • Examples • A typical LSNA measurement session • Next steps in LSNA Technology • Wrap-up Page 33
LSNA Calibration Response Acquisition F0=1GHz Stimulus 50 Ohm or tuner Modulation Source Calibration Reference Planes Actual waves at DUT Measured waves 1GHz 2GHz 3GHz 7 relative error terms same as a VNA Absolute magnitude and phase error term freq Page 34
Relative Calibration: Load-Open-Short Acquisition {f0, 2 f0, …, n f0} Load Open Short 50 Ohm 50 Ohm {f0, 2 f0, …, n f0} F0=1GHz Acquisition Thru 50 Ohm 50 Ohm Calibration for fundamental and Harmonics Page 35
Power Calibration 1GHz 2GHz 3GHz freq Amplitude {f0, 2 f0, …, n f0} Acquisition 50 Ohm Power Meter {f0, 2 f0, …, n f0} F0=1GHz Page 36
Phase Calibration 1GHz 2GHz 3GHz Phase freq {f0, 2 f0, …, n f0} Acquisition f0 ... Reference Impulse Generator 50 Ohm 50 Ohm f0 F0=1GHz Page 37
Measurement Traceability Relative Cal Phase Cal Power Cal Agilent Nose-to-Nose Standard National Standards (NIST) Page 38
Agenda • Introduction • Large-Signal Network Analysis • The Large-Signal Network Analyzer • Calibration • The core of the LSNA Technology • Examples • A typical LSNA measurement session • Next steps in LSNA Technology • Wrap-up Page 39
The heart of the Large-Signal Network Analysis • This hardware is the core that will be used to work with the customer in providing LSNA technology • Combines capabilities of a vector network analyzer, sampling scope and ESG-VSA. • Provides complete waveform analysis capabilities • CW/Multi-tones with harmonics • 0.6 to 20 GHz frequency coverage • 8MHz usable IF BW • 10 W power handling capability Page 40
Agenda • Introduction • Large-Signal Network Analysis • The Large-Signal Network Analyzer • Calibration • The core of the LSNA Technology • Examples • A typical LSNA measurement session • Next steps in LSNA Technology • Wrap-up Page 41
Examples • Transistor reliability • Transistor model verification (ICCAP / ADS) • Transistor model tuning • PA design using waveform engineering • System level characterization • Scattering functions • Memory effect • Dynamic bias Page 42
Gate - Drain Breakdown Current Time (ns) º TELEMIC / KUL º transistor provided by David Root, Agilent Technologies - MWTC Page 43
Forward Gate Conductance Time (ns) º TELEMIC / KUL º transistor provided by David Root, Agilent Technologies - MWTC Page 44
Examples • Transistor reliability • Transistor model verification (ICCAP / ADS) • Transistor model tuning • PA design using waveform engineering • System level characterization • Scattering functions • Memory effect • Dynamic bias Page 45
Use of LSNA measurements in ICCAP model verification, optimisation (and extraction) sweep of Power Vgs Vds Freq ICCAP specific input ADS netlist. Used, a.o., to impose the measured impedance to the output of the transistor in simulation Page 46
Transistor De-embedding Equivalent circuit of the RF test-structure, including the DUT and layout parasitics before de-embedding after Gate current / mA Page 47 Time/period
Input capacitance behaviour Vds,dc=0.3 V Vgs,dc=0.9 V Vds,dc=1.8 V Input loci turn clockwise, conform i=C*dv/dt Page 48
Dynamic loadline & transfer characteristic Vds,dc=0.9 V Vgs,dc=0.3 V Page 49
1.2 1.7 1.1 1.6 1.0 1.5 0.9 v1sts v2sts v1mts_de v2mts_de 0.8 1.4 0.7 1.3 0.6 0.5 1.2 0 100 200 300 400 500 600 700 800 900 0 100 200 300 400 500 600 700 800 900 time, psec time, psec 0.002 0.008 0.001 0.006 0.000 0.004 i1sts i1mts_de i2sts i2mts_de -0.001 0.002 -0.002 0.000 -0.003 -0.002 0 100 200 300 400 500 600 700 800 900 0 100 200 300 400 500 600 700 800 900 time, psec time, psec LSNA identifies modeling problem : extrapolation example SiGe HBT meas. simul. SiGe HBT (model parameters extracted using DC measurements up to 1V)Vbe= 0.9 V; Vce=1.5 V; Pin= - 6 dBm; f0= 2.4 GHz Page 50