Customers/Channels/Technology (How are Needs Changing)

1
Large-Signal Network Analysis Technology to
help the RD Customer
2
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

3
Design Challenge

• Customers are demanding more capabilities/perform
  ance 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
4
Why cant 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
  cant 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

5
Amplifier Measurements
Power in and out
Phase flatness
ACPR
Power Added Efficiency
Device Under Test
Loadpull
6
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
7
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

8
Existing Measurements and Limitations cont
Z1
Z2
DUT
Freq. (GHz)

• 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

9
Existing Measurements and Limitations cont
VNA, SA or Pwr Mtr.
VNA, SA or Pwr Mtr.
Load Tuner(s) (?L )
Source Tuner (?S )
DUT

• 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

10
Existing Measurements and Limitations cont

• 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

11
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

12
Results

• Cut-and-try engineering (designers imagineer
  fixes)
• Design verification consumes 2/3rds of
  development time
• Time-to-market delays
• Unpredictable design processes
• Time consuming tuning and measurement requirements

13
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
  RD environment through this technology

14
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

15
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

16
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)

17
Large-Signal Network Analysis

• Large-Signal
• Refers to potential nonlinear behavior
• Nonlinear behavior -gt 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

18
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)

19
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

20
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
2
4
DC
3
4
DC
3
Z1
DUT
Z2
Freq. (GHz)
1
2
3
4
DC
Complex Fourier coefficients Xh of waveforms
Freq. (GHz)
Freq. (GHz)
1
1
2
3
4
DC
2
3
4
DC
21
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
2
4
DC
3
4
DC
3
time
time
X3(t)
Slow change (MHz)
Z1
DUT
Z2
Fast change (GHz)
Freq. (GHz)
1
2
3
4
DC
time
Complex Fourier coefficients Xh(t) of waveforms
Freq. (GHz)
Freq. (GHz)
1
1
2
time
3
4
DC
2
3
4
DC
time
22
Periodic Modulated Signals
Phase
X1i
Amplitude
X0i
X2i
Phasor
X3i
Freq. (GHz)
Freq. (GHz)
1
1
Periodic Modulation
3
2
3
DC
2
DC
Z1
DUT
Z2
Freq. (GHz)
1
2
3
4
DC
Complex Fourier coefficients Xhm of waveforms
Freq. (GHz)
Freq. (GHz)
1
1
3
2
DC
3
2
DC
23
Waves (A, B) versus Current/Voltage (V, I)
From device to system level
24
Small-Signal Network Analysis S-parameters
Measurement System
Measurement System
Transistor RFIC System
Transistor RFIC System
Experiment 1
Experiment 2

• Analysis

25
Large-Signal Network Analysis
Measurement System
Transistor RFIC System
Different Experiments

• Analysis

26
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

27
Vector Network Analyzer Measurement
Response
Stimulus
Calibration
Reference Planes
S-parameters
Linear Theory
28
Large-Signal Network Analyzer
Response
Acquisition
Stimulus
50 Ohm or tuner
Modulation Source
Calibration
Reference Planes
Complete Spectrum Waveforms Harmonics and
Periodic Modulation
29
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
30
Harmonic Sampling - Signal Class CW
IF Bandwidth 4 MHz
fLO19.98 MHz (1GHz-1MHz)/50
RF
50 fLO
100 fLO
150 fLO
1
2
3
Freq. (GHz)
IF
Cutt Off IF
2
3
Freq. (MHz)
1
31
Harmonic Sampling - Signal Class Periodic
Modulation
fLO19.98 MHz (1GHz-1MHz)/50
RF
50 fLO
100 fLO
150 fLO
1
2
3
IF
IF Bandwidth 4 MHz
3
2
1
Freq. (MHz)
32
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
33
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

34
LSNA Calibration
Response
Acquisition
F01GHz
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
35
Relative Calibration Load-Open-Short
Acquisition
f0, 2 f0, , n f0
Load Open Short
50 Ohm
50 Ohm
f0, 2 f0, , n f0
F01GHz
Acquisition
Thru
50 Ohm
50 Ohm
Calibration for fundamental and Harmonics
36
Power Calibration
1GHz
2GHz
3GHz
Amplitude
freq
f0, 2 f0, , n f0
Acquisition
50 Ohm
Power Meter
f0, 2 f0, , n f0
F01GHz
37
Phase Calibration
1GHz
2GHz
3GHz
Phase
freq
f0, 2 f0, , n f0
Acquisition
f0
...
Reference Impulse Generator
50 Ohm
50 Ohm
f0
F01GHz
38
Measurement Traceability
Relative Cal
Phase Cal
Power Cal
Agilent Nose-to-Nose Standard
National Standards (NIST)
39
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

40
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

41
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

42
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

43
Gate - Drain Breakdown Current
Time (ns)
º TELEMIC / KUL
º transistor provided by David Root, Agilent
Technologies - MWTC
44
Forward Gate Conductance
Time (ns)
º TELEMIC / KUL
º transistor provided by David Root, Agilent
Technologies - MWTC
45
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

46
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
47
Transistor De-embedding
Equivalent circuit of the RF test-structure,
including the DUT and layout parasitics
before
de-embedding
after
Gate current / mA
Time/period
48
Input capacitance behaviour
Vgs,dc0.9 V
Vds,dc0.3 V
Vds,dc1.8 V
Input loci turn clockwise, conform iCdv/dt
49
Dynamic loadline transfer characteristic
Vgs,dc0.3 V
Vds,dc0.9 V
50
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 Vce1.5 V
Pin - 6 dBm f0 2.4 GHz
51
LSNA identifies modeling problem extrapolation
example SiGe HBT
SiGe HBT - DC characteristics
Measurement
Simulation
Alcatel Microelectronics and the Alcatel
SEL Stuttgart Research Center teams are
acknowledged for providing these data.
52
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

53
Empirical Model Tuning
Parameter Boundaries
GaAs pseudomorphic HEMT gate l0.2 um w100 um
MODEL TO BE OPTIMIZED
Chalmers Model
generators apply LSNA measured waveforms
Power swept measurements under mismatched
conditions
º Dominique Schreurs, IMEC KUL-TELEMIC
54
Using the Built-in Optimizer
During OPTIMIZATION
Voltage - Current State Space
voltage
current
gate
drain
gate
drain
Time domain waveforms
Frequency domain
55
Verification of the Optimized Model
AFTER OPTIMIZATION
Voltage - Current State Space
voltage
current
gate
drain
gate
drain
Frequency domain
Time domain waveforms
56
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

57
Waveform Engineering Block Diagram
Source
f0
Sampling Converter
PC
Data-Acquisition
Test Set
DUT
f0
3f0
IRCOM Setup
2f0
58
Example - Measured Waveforms
MesFET Class F f01.8 GHz Ids07 mA Vds0 6 V
PAE?50
Waveform Engineering
Z(f0)130j73 ? Z(2f0)1-j2.8 ? Z(3f0)20-j97 ?
PAE84
º IRCOM / Limoges
59
Example - Performance Improvement
Derived Information from the V/I waveforms (swept
input power at different terminations)
Z(f0)123j72 ? Z(2f0)50 ? Z(3f0)50 ?
PAE?74
Z(f0)123j72 ? Z(2f0)2 - j 4.0 ? Z(3f0)50 ?
PAE?74
Z(f0)123j72 ? Z(2f0)2 - j 4.0 ? Z(3f0)21-96 ?
PAE?84
º IRCOM / Limoges
60
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

61
RFIC Amplifier Characterization using periodic
modulation
a1
Modulation Source
E1
f0 1.9 GHz
Evaluation Board
A1 shows spectral regrowth

• Spectral regrowth on b1
• combined with measurement
• system mismatch
• Nonlinear pulling on source

a1
5 dB
E1
62
Transmission Characteristics
Carrier Modulation
A1
B2
Carrier Modulation
Harmonic Distortion
Compression
Carrier Modulation
3rd harmonic Modulation
63
Reflection Characteristics
Carrier Modulation
A1
B1
Carrier Modulation
Harmonic Distortion
Expansion
Carrier Modulation
2nd harmonic Modulation
3rd harmonic Modulation
64
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

65
Scattering Functions provide device understanding
and enable CAE couplingTuners and active
injection at harmonics
_at_ fundamental frequency
_at_ higher harmonics
66
Nonlinear behaviour and Scattering Functions
Functions of
(and independent bias settings)
Index of Port harmonic Note as and bs are
phase normalized quantities !!
As shown before for small-signal levels (linear)
this reduces to (fundamental at port 2)
67
Scattering functionsvariation versus input power
68
Generated reflection coefficients at port 2 at f0
Generated ?s
(a)
?s for verification meas.
69
Time domain waveformsmeasured and simulated
b-waves
70
Application of CDMA-like signal
71
Frequency domain
fc2.45 GHz, ?f ? 50 kHz, modulation BW ? 1.45
MHz redmeasured, bluemodel
72
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

73
Time domain
Memory effects !
74
Memory effectsDUT behaviour under 2-Tone
excitation
Modulation frequency 20 kHz
Modulation frequency 620 kHz
75
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

76
What is Dynamic Bias Behaviour?
Output Current
Input Voltage
Freq. (GHz)
1
2
DC
Freq. (GHz)
1
DC
Dynamic Bias Behaviour
Frequency Domain Generation of Low Frequency
Intermodulation Products
Time Domain Beating of the Bias
77
Dynamic Bias Measurement Principle
Bias 1 Supply
Bias 2 Supply
Current Probe
Current Probe
TUNER
78
RFIC Example in Time Domain
MultiLine TRL
Input Voltage Waveform
(V)
Normalized Time
Output Current Waveform (without Dynamic Bias)
(mA)
Normalized Time
79
Adding Measured Dynamic Bias
Dynamic Bias Current Waveform
(mA)
Normalized Time
Output Current Waveform (including Dynamic Bias)
(mA)
Normalized Time
80
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

81
LSNA possible next steps driven by customer needs

• Extending modulation BW (3G)
• Increase power capability
• Extending frequency range (50 GHz and beyond )
• Offer pulsed measurements to isolate the thermal
  effects
• Complete dynamic bias testing capabilities to
  characterize the effects of modulation on bias
• Add impedance tuning measurements to determine
  the impact of differing impedance conditions
• Use of LSNA technology in high speed digital
  applications

82
Example Extending Power Capability
Acquisition
Stimulus
?
Modulation Source
Calibration
Reference Planes
Pre-matching Proper calibration elements On -
board DC bias Tuners
Adapt test - set Proper absolute
calibration Measurement science
Agilent NMDG
3rd party
83
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

84
Wrap-up

• Large-Signal Network Analysis Technology is
  breakthrough technology to characterize nonlinear
  behavior from transistor to system
• The technlogy is targeted toward research and
  design experts. It requires a strong background
  in RF or Microwave theory to be successful.
• Agilent NMDG is assigned to make the technology a
  success with early-adopter key customers
• More information at http//wirelesscentral.tm.a
  gilent.com/wirelesscentral/cgi-bin/epsg.cgi
• If you think the LSNA technology can help you,
  please contact Marcus_VandenBossche_at_agilent.com