Advanced Component Characterization and Modeling

Advanced Component Characterization and Modeling
From Small-Signal to Large-Signal - All in One -

Outline Introduction Component Characterization
A Large-Signal Network Analyzer The Absolute Calibration The MT The Hardware The MT All in One - MT4463 Modules High - Impedance Probing Real-Time PA Analysis Measurement-Based Behavioral Modeling Component Characterization and Modeling Services Conclusion

A Vector Network Analyzer
f0 A Vector Network Analyzer LINEAR BEHAVIOR f0 f0 Measurement System Measurement System Transistor RFIC System Transistor RFIC System Experiment 1 Superposition Experiment 2 Analysis f0

Component Characterization
DC Characterization S-parameters at different bias points (option: pulsed) Nonlinear Characteristics: Compression, AM-AM and AM-PM, TOI, Harmonic Distortion, Spectral Re-growth, Source- and Load-pull etc …. ???? STRAIGHTFORWARD POSSIBILITIES MANY

Component Characterization
Source and Load Tuning Active HF Power Meter 50 Ohm Termination Linear S-parameters Compression Delivered Power Vector Network Analyzer Power Meter Active HF Active HF Spectrum Analyzer Active HF Power Meter Harmonics Compression Active HF Power Meter Power Meter Harmonics In-circuit Inspection Active HF Spectrum Analyzer Oscilloscope Different Setups for different aspects without systematic approach Vector Signal Generator Active HF Vector Signal Analyzer Spectral Regrowth How to help the circuit designers, needing good models?

A Large - Signal Network Analyzer
f0 2f0 3f0 ... A Large - Signal Network Analyzer NONLINEAR BEHAVIOR Measurement System Realistic Stimulus Realistic Stimulus Transistor RFIC System MEASURING Travelling Waves (A, B) Voltage/Current (V, I) AT THE COMPONENT PORTS REPRESENTING IN Frequency (f) Time (t) Freq - time (envelope) Meas-based model Characterization Analysis

Component Characterization under CW Stimulus
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 DC 2 3 4 DC 2 3 4 Z1 DUT Z2 Freq. (GHz) 1 The simplest measurement solution deals with a continuous wave (CW) excitation (one-tone) of 2-port devices, e.g. a biased FET-transistor excited by a CW signal (for example at 1 GHz) at the gate, with an arbitrary load at the drain. Assuming that the device is stable (not oscillating) and does not exhibit subharmonic or chaotic behavior, all current and voltage waveforms will have the same periodicity as the drive signal (in this case 1 ns). This implies that all voltage and current waveforms (or the associated travelling voltage waves) can be represented by their complex Fourier series coefficients. These are called the spectral components or phasors. (One calls the 1GHz component the fundamental, the 2GHz component the 2nd harmonic, the 3GHz component the 3rd harmonic,…) The DC components are called the DC-bias levels. In practice there will only be a limited number of significant harmonics. The measurement problem is as such defined as the determination of the phase and amplitude of the fundamental and the harmonics, together with the measurement of the DC-bias. The set of frequencies at which energy is present and has to be measured is called “the frequency grid”. All frequencies of the grid are uniquely determined by an integer (h), called the “harmonic index”, compared to the fundamental frequency or the carrier. DC 2 3 4 Complex Fourier coefficients Xh of waveforms Freq. (GHz) Freq. (GHz) 1 1 DC 2 3 4 DC 2 3 4

Component Characterization under Modulation
Phase X1(t) Amplitude X2(t) X0(t) X4(t) Phasor Freq. (GHz) Freq. (GHz) 1 1 Modulation time DC 2 3 4 time DC 2 3 4 X3(t) Slow change (MHz) Z1 DUT Z2 Fast change (GHz) Freq. (GHz) 1 time Suppose now that we change the amplitude and phase of the one - tone source over time. As effect we will see all spectral components of the signals at the component under test change over time. This results for each phasor in a complex time signal. One will see that the DC will start to change over time. This is referred to as dynamic bias. To detect the time-varying spectral components properly (without leakage), it is necessary to make the modulation also periodic. DC 2 3 4 Complex Fourier coefficients Xh(t) of waveforms Freq. (GHz) Freq. (GHz) 1 1 time DC 2 3 4 time DC 2 3 4

Component Characterization under Periodic Modulation
Phase X1i Amplitude X0i Phasor X2i X3i Freq. (GHz) Periodic Modulation 1 Freq. (GHz) 1 DC 2 3 DC 2 3 Z1 DUT Z2 Freq. (GHz) 1 DC 2 3 4 As an example, consider the same FET transistor whereby one modulates the 1GHz signal source, such that the modulation has a period of 10kHz. Therefore, the phasors will be complexe time functions, as explained in previous slide, but with a periodicity of 10 kHz. So, it is now possible to apply a Fourier transform on the compexe time signal of each phasor. Therefore the voltage and current waveforms will now contain many more spectral components. New components will arise at integer multiples of 10kHz offset relative to the harmonic frequency grid. In practice significant energy will only be present in a limited bandwidth around each harmonic. The resulting set of frequencies is called a “dual frequency grid”. Note that in this case each frequency is uniquely determined by a set of two integers, one denoting the harmonic frequency, and one denoting the modulation frequency. E.g. harmonic index (3,-5) denotes the frequency 3GHz - 50kHz. The measurement problem will be to determine the phase and the amplitude of all relevant spectral components of current and voltage. With the proper processing the class of signals, discussed up to now, can be extended to any multi-tone signal (commensurate or none-commensurate). Complex Fourier coefficients Xhm of waveforms Freq. (GHz) 1 1 Freq. (GHz) DC 2 3 DC 2 3 The class of signal is extendable to any type of multi-tone signal

Large-Signal Network Analyzer
Response Acquisition Stimulus Modulation Source 50 Ohm or tuner Reference Planes Calibration A Large-Signal Network Analyzer looks similar to a vector network analyzer. There is a broadband test - set to separate incident and reflected waves. A microwave source or a vector signal generator can inject a one tone or periodic modulated signal into the component under test. If this component is nonlinear, it will generate harmonics in its reflection and transmission. These harmonics are reflected back by the mismatch created by the measurement system. A broadband acquisition system is able to take proper samples of these broadband incident and reflected waves. To create realistic operating conditions it is possible to connect to the system passive or active source and load impedance tuners. In contrast to the VNA, where the source is an integral part of the measurement system, the LSNA is a calibrated data acquisition system with a lot of freedom related to the excitation scheme. The main restriction is that all sources must be synchronized from the reference clock. Remark also that the measurement system is AC coupled towards the stimulus at port 1 and at port 2. This prevents the flow of DC current towards the stimulus. One needs to be aware that this enforces possibly a certain DC condition on the device under test when it is not AC coupled by itself. With the proper calibration techniques, the systematic errors of the measurement system are eliminated. The complete spectrum (amplitude and phase) of incident and reflected waves can be acquired and the time waveforms reconstructed. Complete Spectrum Waveforms Harmonics and Periodic Modulation

Acquisition in LSNA LO Sampling Converter PC Acquisition Unit Filter
The broadband acquisition system consists of a sampler front - end in combination with a low - frequency (intermediate frequency or IF) data acquisition system. The sampler front - end compresses broadband signals into a low - frequency version which then can be digitized and processed. The advantage of a sampler is that it converts all spectral content into a low - frequency version, the disadvantage is that it is doing this also with all the noise and spurious within the measurement bandwidth. Usually the sampler is preceded by some signal conditioning, like attenuators, to keep the power incident to the samplers low enough to avoid sampler compression. Because of the compression of a large HF band into a limited IF band, the signals cannot have a continuous spectrum. After sampling it still must be possible to reconstruct the original signal and as such no overlap of spectral content may happen after compression. LO

Harmonic Sampling - Signal Class: Continuous Wave
LP fLO=19.98 MHz = (1GHz-1MHz)/50 1 MHz RF 2 MHz 50 fLO 100 fLO 150 fLO 3 MHz 1 2 3 IF Bandwidth Here, the sampling process is explained in more detail. Suppose one wants to acquire a signal consisting of a fundamental at 1 GHz and containing 3 harmonics using a data acquisition with an IF bandwidth of 4 MHz. If one uses a sampler driven at 20 MHz, one will sample the signal (repetition rate of 1 ns) each 50 ns, corresponding to the repeated sampling (once each 50 periods) of the same value. As a result the output will be DC. If we now de-synchronize the sample rate, by changing it to a frequency lower than 20 MHz, suddenly a beating signal becomes available at the output of the sampler that can be digitized. If we select a sample frequency of MHz, the 1 GHz component will result into a 1 MHz component because the 50th spectral component of the applied sample frequency is 1 MHz away of 1 GHz. The second harmonic will be brought down to 2 MHz because the sampling signal has a spectral component which is 2 MHz away from 2 GHz, etc …. IF 1 2 3 Freq. (MHz)

Harmonic Sampling - Signal Class: Narrowband Modulation
LP fLO=19.98 MHz = (1GHz-1MHz)/50 1 MHz RF 2 MHz 50 fLO 100 fLO 150 fLO 3 MHz 1 2 3 Suppose now that the 1 GHz tone (and harmonics) is slowly modulated. This results in skirts in the IF domain. As long as the skirts are limited (or the modulation is mild) the signal can be detected properly (even using a one-shot data-acquisition). When the modulation becomes broader, at a certain moment the skirts will overlap and the original signal cannot be reconstructed. The allowed modulation bandwidth depends on the IF bandwidth and the number of harmonics of interest. When the modulation would be periodic the modulation spectrum would not be continuous but discrete. At that moment, with some intelligent selections of the sampling frequency, one can take care that the resulting spectral components do not overlap. It is also important to notice that in “narrowband modulation”, the spacing of the modulation frequencies at IF equals that of the spacing at RF. IF IF Bandwidth 1 2 3 Freq. (MHz)

Harmonic Sampling - Signal Class: Broadband Modulation
LP BW 2BW MHz Adapted sampling process BW RF 150 fLO 1 2 3 Freq. (GHz) IF When the modulation is periodic, it is possible to fold the spectrum around each harmonic together into a bandwidth which is only half of the modulation bandwidth. Once the spectrum is folded it is downconverted into the IF bandwidth of the data - acquisition system and digitized and processed. In this way it is possible to double the IF - bandwidth. Freq. (MHz) BW of Periodic Broadband Modulation = 2* BW IF data acquisition

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 Due to restrictions enforced by the practical measurement implementations (the use of a sampler front end) for the large-signal characterization of RF and microwave components, only periodic stimuli will be considered to study the behavior of components. Typically for telecommunications the signals will consist of a carrier and harmonics and are periodic as such and periodic modulation. For wireline applications these will be periodic bitstreams. We also will study only devices that maintain periodicity. So we will not consider oscillators, neither devices with chaotic behavior.

LSNA Calibration Acquisition Response Stimulus Reference Calibration
F0=1GHz Stimulus Modulation Source 50 Ohm or tuner Reference Planes Calibration With the proper calibration techniques, the systematic errors of the measurement system are eliminated. The complete spectrum (amplitude and phase) of incident and reflected waves can be acquired and the time waveforms reconstructed. During an experiment we want to know the phases and amplitudes of a discrete set of spectral components at the DUT signal ports. These quantities are called the ”DUT quantities” and are denoted by a superscript “DUT”. Unfortunately we do not have direct access to these quantities. The only information we can get are the uncalibrated measured values. These are called the “raw measured quantities” and are denoted by a superscript “m”. At all times it is made sure that the Large-Signal Network Analyzer stays within its linear region of operation attenuating the signals timely and properly entering the samplers. Because the LSNA is linear by itself in operation, a linear relationship exists between the raw measured quantities and the DUT quantities. This relationship is expressed in a 4x4 matrix. This matrix is a function of the frequency and is typically calculated on the fundamental and harmonics. It is always possible to bring out a factor out of the calibration matrix. This factor is called the K-factor. To perform a large-signal network analysis this K-factor must be known as a function of frequency. The K-factor of the matrix requires a power meter (amplitude of K) and a reference generator (phase of K). Actual waves at DUT Measured waves 1GHz 2GHz 3GHz 7 relative error terms same as a VNA freq Absolute magnitude and phase error term

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 The relative calibration is exactly the same as for a vector network analyzer. Referring to an example where one wants to characterize a transistor on a frequency grid of 1 GHz with 20 harmonics, the microwave source is stepped in steps of 1 Ghz from 1 GHz to 20 GHz and measuring the S-parameters of known linear devices (load, opens, short, thru). 50 Ohm Thru 50 Ohm Calibration for all multi - tones

Power Calibration Acquisition {f0, 2 f0, …, n f0} Power Meter 50 Ohm
freq 1GHz 2GHz 3GHz Amplitude {f0, 2 f0, …, n f0} Acquisition {f0, 2 f0, …, n f0} Power Meter 50 Ohm For the power calibration a power meter is connected to “Port 1” of the system. The source is stepped through the frequency grid (in our example from 1 GHz to 20 GHz in steps of 1 GHz). For each step the power is measured and calculated through the acquisition system. This results into a distortion table as function of the frequency. Measuring on wafer, the calibration reference planes correspond to the probe tips. Therefore, “Port 1” is connected to “Port 2” via a line on wafer and an additional load-open-short calibration is done at the port with the 50 Ohm load while stepping the source in steps of 1 GHz. Then the power meter is connected at that point and the source is stepped again. With some calculations and the reciprocity principle the power can be referred back to “Port 1”. f0 = 1GHz

Phase Calibration Acquisition ... f0 Harmonic Phase 50 Ohm 50 Ohm
freq 1GHz 2GHz 3GHz Phase {f0, 2 f0, …, n f0} Acquisition f0 ... 50 Ohm Harmonic Phase Reference 50 Ohm For the phase calibration the harmonic phase reference (HPR) is connected to “Port 1” of the LSNA. In the example, the source generates a one tone at 1 GHz, driving the HPR. The HPR generates pulses with a repetition rate of 1 ns. In the frequency domain this corresponds to spectral components on a frequency grid of 1 GHz. At manufacturing time, this generator is very accurately calibrated in phase in a traceable way as function of generated harmonic and the drive frequency. To calibrate the reference the nose nose calibration process is used or another traceable approach. f0 f0 = 1GHz

Measurement Traceability
Relative Cal Phase Cal Power Cal Agilent Nose-to-Nose Standard (*) EOS For now, the relative calibration and the power calibration of the LSNA are traceable to national standard labs. The phase calibration is traceable to a nose-to-nose (n-2-n) standard, developed at Agilent and licensed to Maury and NMDG. NIST has been and is actively involved in the traceability of nose-to-nose. Meanwhile, standard labs like NIST, NPL and possibly others, made progress on the development of an Electro-Optical sampling system which also can be used to characterize pulse standards. Discrepancies have been found between the n-2-n and the EOS approach which need to be dealt with above 20 GHz. NIST is also investigating the complete LSNA phase calibration. (NIST) (demonstrated already with NIST) National Standards (*) Licensed to Maury and NMDG

MT4463 MT4463B - 50 GHz MT4463A - 20 GHz

Adapting MT4463 to different needs
Modulation Characterization DC IV Characterization Active HF Component Characterization Small-Signal Large-Signal Adding … DC Capability Adding … Modulation Capability Accurate Complete MT4463A/B Active Tuning Passive Tuning Under different Impedance Conditions Adding … Tuners Adding … Pre-match Tuner … Second Source

Harmonic Phase Reference
MT4463A - 20 GHz Harmonic Phase Reference Amplifier Power Meter Power Sensor Pulse Generator PC Acquisition Unit System Source Sampling Converter Test Set Test Board

Harmonic Phase Reference
MT4463B - 50 GHz Harmonic Phase Reference Amplifier Power Meter Power Sensor Pulse Generator PC Acquisition Unit System Source Sampling Converter Test Set - Calibration Module Test Set - Reflectometers

The Test Set - 50 GHz - On Wafer
MT4466B001 Calibration Module Reflectometer Reflectometer

The Software LSNA v1.1.0 DC Characterization (using script)
Small - Signal: S-parameters Large - Signal: Provides calibrated measurements of voltages and currents or incident and reflected waves in reference planes at the device under test under periodic stimulus in mismatched conditions Graphical User Interface supporting basic functionality Control Data Visualization Open system Powerful scripting language to develop own applications API to connect into your tools MATLAB LabVIEW ...

Easy control via GUI Configure System Calibrate System SOLT LRRM TRL
De-embedding Modulation Ranging Save data

DC calibration eliminates the cable losses
Calibration using GUI SOLT Calibration In this case: DC is not applied via bias tees but separately via port 3 and 4 DC calibration eliminates the cable losses

From small - signal to large - signal with ONE connection
Commercial available FET in fixture Test Port 1 Test Port 2 Absolute Calibration Bias Control Deembedding Synthesizer Control Vgs = -0.3 V Vds = 1.5 V

Measuring S-parameters
Persistency mode Power Control at Port 1 Power Control at Port 2 S11 Markers S12 S21 S22 Frequency Range: 600 MHz – 20, 40 or 50 GHz (depending on Test Set and Source) Supported Calibration techniques: SOLT, LRRM, TRL

Large-Signal Measurements - CW - Voltage/Current
Time domain

Large-Signal Measurements - CW - Voltage Waves
Time domain

Large-Signal Measurements - CW - Voltage/Current
Frequency domain

DC-IV curve and load line
Small-signal - 50 Ohm Termination Large-signal - non-50 Ohm Termination Large-signal - 50 Ohm Termination

Input and Load impedance under CW
Impedance at 2nd harmonic non-50 Ohm Termination Impedance at fundamental non-50 Ohm Termination

Periodic Modulation - Multi-tone generation
Carrier Modulation Tones Generation of Multi-tone

Large-Signal Measurements - Modulation - Voltage/Current
Frequency domain

Zoom into one of the spectral components Frequency domain

Frequency - Time domain

Dynamic AM/AM and AM/PM (two-tone 2kHz spacing)

Dynamic HDA (two-tone 2kHz spacing)

Powerful Scripting Language
Fast development of prototypes and new applications, exploiting all MT4463 capabilities, using Mathematica™

Connecting to your development tools
Stimulus Response DLL Connection via LabVIEW C-callable Talk to your instruments through your own tools Data export Citifile Table CSV Connection via C-program Connection via others

In-Circuit coherent and calibrated HF Signal Probing(*)
5 8 10 12 13 14 15 Pin (dBm) (*) With courtesy of CNES and IRCOM

Real-Time PA Analysis - Setup
MT4463 2f0 (optional) i1 i2 Triplexer f0 DUT f0 v1 v2 3f0 (optional) Offset + smart signal to scan amplitude and phase

Real - time PA Analysis and Load pull
Power source on-wafer FET 2 GHz vG=-0.9V vD=3.0V Gain Reactive Power Harmonic Power...

Real-time load-pull Compared to classical load-pull
Level of 3rd harmonic 17 dB down, 2nd harmonic 22 dB down = 0.1 added to power at fundamental max Pdel dBm dBm harmonics (0.1 dB) @ j 8.5 W j 7.1 W flat surface 4 additional points: |D| < 0.1 dB

Measurement - Based Behavioral Model Setup and boundaries
sweep power grid a2 equid. region mismatch Same setup as during real-time load-pull, but 2nd source doesn’t need modulation capability

Integration of model into simulator (ADS)
FDD + DAC component CITI file regular grid no triangulation required

Verification of model (load-pull)
contours based on HB simulations on regular polar grid using MBBM imported into ADS contours based on classical load-pull data imported into ADS after triangulation Comparing the contour plots of the power delivered to the load predicted by the model (blue solid line + circles) and based on a classical load-pull measurement (red solid line).

Verification of model (source-pull)
contours based on HB simulations on regular polar grid using MBBM imported into ADS contours based on classical source-pull data imported into ADS after triangulation Comparing the contour plots of the power delivered to the load predicted by the model (red solid line) and based on a classical source-pull measurement (blue solid line + circles). ALERT: Colors swapped (because circles on model-based contours too dense)

Model Capabilities Compression / Gain
Source - and Load - pull with most power characteristics Modulation Prediction (even under mismatches) Mismatched Condition QPSK at input QPSK at output Spectral Re-growth at input at output Output Power Dynamic Compression Input Power

NMDG Characterization Service
With one single connection to the component, you get DC I-V characteristics S-parameters at different bias points Broadband voltage and current waveforms at the input and output of the test device including fundamental, harmonic and modulation behaviour for different bias conditions, powers and at different frequencies under continuous wave stimulus under different impedances Diodes Transistors Amplifiers (De)Modulators RF Switches O/E components RF MEMS ...

NMDG Characterization Service
With one single connection to the component, you get Dynamic Loadlines Intermodulation / IM3 - Static and Dynamic Harmonic Distortion Analysis (amplitude and phase) - Measurement data connection in circuit design tools - … and many more on request

NMDG Advanced Characterization Service
Requires customized engineering Hot S-parameter measurements Stability analysis under hot conditions Large-signal measurements under pulsed conditions Measurement of input impedance of sources, oscillators under hot conditions Conversion matrices Characterization of frequency translating devices, e.g. mixers In-circuit measurements using high-impedance or active probes On request: Other large-signal characteristics can be measured

NMDG Modeling Service Only Measurement - Based Behavioral Models
Capabilities Accurate and complete at a specified fundamental frequency for a given input power range and a range of source and load impedances The bias circuitry is assumed to be part of the component Modulation prediction is possible under quasi-static assumptions Key Values Fast availability of accurate model speeds up concurrent design Simulate your active HF components under mismatched conditions, fast and accurately

HF Measurement System Consulting
Closing the gap between instruments and the increasing complexity to characterize and test HF active components and circuits Key Values Focus on your design and production, not on developing measurement systems Eliminate the guess work in your measurements by adding the proper calibration Extend your signal analysis capability to in-circuit testing through software and additional hardware NMDG offers ... Graphical User Interface Development Circuit Design Tools Signal Processing and Algorithm Development Instrument Control

In - circuit HF Signal Testing with calibration at the component Stimulus - Response Measurement System for HF and High-Speed Signals Correction Coefficients Calibration Software Calibration Planes

In - Circuit coherent and calibrated HF Signal Probing (*) 5 8 10 12 13 14 15 Pin (dBm) (*) With courtesy of CNES and IRCOM

NMDG HF System Consulting
Conclusion MT4463 is one instrument to study the nonlinear behavior in all its aspects from small - signal to large -signal with one connection under CW and modulation condition in mismatched environments MT4463 it is the only instrument providing the complete state of a component, compatible with present simulators MT4436 is designed to evolve over - time securing your investment NMDG Characterization and Modeling Service give you The MT4463 Experience at low risk NMDG HF System Consulting brings NMDG Expertise to your bench

Advanced Component Characterization and Modeling

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