pulsed-bias load pull

Hybrid-Active Load Pull With PNA-X And Maury
Microwave
Steve Dudkiewicz
Director, Marketing & Business Development
[email protected]
© Agilent Technologies, Inc 2012
OUTLINE
– Background Info
– Vector-Receiver Load Pull
– Active and Hybrid-Active Load Pull
– X-Parameters and Active/Hybrid-Active Load Pull
– Pulsed-Bias Load Pull
– Conclusion
© Agilent Technologies, Inc 2012
BACKGROUND INFO
# GHz S
MA
R
! FREQ
S11M
0.040000 1.157518E-01
0.121200 1.266560E-01
0.202400 1.290937E-01
0.283600 1.067625E-01
0.364800 8.738539E-02
0.446000 8.056434E-02
0.527200 7.555955E-02
0.608400 7.497411E-02
0.689600 7.295863E-02
0.770800 7.386764E-02
0.852000 7.318650E-02
0.933200 7.235688E-02
1.014400 7.233581E-02
1.095600 7.225432E-02
1.176800 7.313726E-02
1.258000 7.385175E-02
50.00
S11A S21M
S21A
S12M
S12A
S22M
S22A
-3.710 5.922372E+00 -5.243 6.274591E-04 -21.162 1.911442E-01 168.563
-15.896 5.750123E+00 -15.489 1.689511E-04 138.045 2.034910E-01 164.212
-41.697 5.694812E+00 -26.094 1.534801E-04 154.615 1.996204E-01 148.486
-58.433 5.575610E+00 -35.371 2.154534E-04 68.351 1.841301E-01 136.932
-68.825 5.682967E+00 -43.513 2.096765E-04 65.455 1.694200E-01 125.748
-73.308 5.930343E+00 -53.585 5.399332E-04 5.607 1.544818E-01 116.827
-80.844 6.136280E+00 -64.610 1.042182E-04 142.124 1.402974E-01 108.840
-86.870 6.263798E+00 -77.026 3.081686E-04 71.327 1.230561E-01 102.798
-93.382 6.136727E+00 -90.779 1.510877E-04 116.547 1.172368E-01 103.797
-99.298 6.036165E+00 -101.499 3.284408E-04 129.861 1.095949E-01 92.296
-105.194 5.848570E+00 -112.455 8.395422E-05 87.645 9.591621E-02 87.389
-112.088 5.702302E+00 -121.464 1.231399E-04 -172.694 8.493296E-02 88.087
-120.186 5.733521E+00 -129.912 1.999466E-04 52.778 7.911136E-02 89.575
-127.552 5.892607E+00 -139.328 4.801104E-05 60.708 7.587810E-02 89.600
-135.538 6.100566E+00 -149.979 3.209557E-04 16.738 6.707616E-02 97.937
-143.046 6.240838E+00 -161.795 2.506652E-04 51.531 7.620265E-02 111.163
For a small-signal application, the S-Parameters can be measured by a Vector
Network Analyzer (VNA), and the complex conjugates of S11 and S22 used to create
input and output matching networks for maximum gain and power
Note: this only works for small-signal, DO NOT USE FOR POWER APPLICATIONS!
3
© Agilent Technologies, Inc 2012
BACKGROUND INFO
If small-signal s-parameters are used to determine the complex conjugate of S11 and
S22 for a matching network, the output power, gain, efficiency… will not be at its
maximum..
The above Smith Charts show the same impedance matching at different input power
levels (small signal and large signal); note the large signal output power is down 3dB
4 from its maximum (3dB = 50%!)
© Agilent Technologies, Inc 2012
BACKGROUND INFO
1) Vary impedance presented to
DUT (active device, transistor)
Highest Pout
2) Measure Pout, Gain,
Efficiency…
3) Determine best matching
impedance
4) Design matching network (EEsof
ADS)
© Agilent Technologies, Inc 2012
BACKGROUND INFO
VSWR α Gamma α 1/Ω
10:1 VSWR = Γ=0.82 = 5Ω
20:1 VSWR = Γ=0.9 = 2.5Ω
Γ = a/b
Y
Probe
X
Mechanical Tuner
Gamma comes from probe
(slug) inserted into airline
Airline
X
Y
Probe
Airline
© Agilent Technologies, Inc 2012
BACKGROUND INFO
(optional
)
In Traditional Load Pull, delivered output power is calculated from Power Meter de-embedded
through S-Parameter block and Impedance Tuner
Available input power is calculated from gain lookup table created during power calibration or
from input Power Meter and then de-embedded through S-Parameter block and Impedance
© Agilent Technologies, Inc 2012
Tuner
BACKGROUND INFO
Large signal input impedance, Zin,
changes as function of:
- Drive power
- Zload
Traditional load pull matches source
impedance at single power, not taking
into account varying Zin during power
sweep
© Agilent Technologies, Inc 2012
BACKGROUND INFO
Gain values look low because only Pin,available is
used… reflected power due to mismatch is not
taken into account
Traditional load pull only reports Transducer Gain
© Agilent Technologies, Inc 2012
OUTLINE
– Background Info
– Vector-Receiver Load Pull
– Active and Hybrid-Active Load Pull
– X-Parameters and Active/Hybrid-Active Load Pull
– Pulsed-Bias Load Pull
– Conclusion
© Agilent Technologies, Inc 2012
VECTOR-RECEIVER LOAD PULL
Network Analyzer
Low-loss
Coupler
Signal Source Amplifier Impedance Tuner
Pout
Pin ,del
1
b2
2
2
1
2
a1
2
a2
1
b2
2
2
b1
2
2
1 2
a1
2
Low-loss
50Ω Load
Coupler Impedance Tuner
2
1
load
1
Gp
2
in
PAE
Pout
Pin ,del
b2
Pout
Pin ,del
2
a1
1
2
1
2
load
2
in
PDC
© Agilent Technologies, Inc 2012
VECTOR-RECEIVER LOAD PULL
Gain values look low because only
Pin,available is used… reflected power due
to mismatch is not taken into account
Knowing Zin allows us to calculate
Power Gain, taking into account
mismatch thereby showing true gain
potential of device
© Agilent Technologies, Inc 2012
VECTOR-RECEIVER LOAD PULL
Traditional LP
Vector Receiver LP
Pre-Characterization
Required
Recommended (not
required)
Number of Points
More points = greater
accuracy (even with
interpolation)
Minimum points required
(no impact on accuracy)
Tuner De-embedding
Critical! (Accuracy relies
on de-embedding)
No tuner de-embedding
Network Analyzer
Power Meter
Spectrum
Analyzer
Power
Sensor
Signal Source
Amplifier
Impedance Tuner
Impedance Tuner
Power
Sensor
Low-loss
Coupler
Signal Source Amplifier Impedance Tuner
Low-loss
50Ω Load
Coupler Impedance Tuner
© Agilent Technologies, Inc 2012
VECTOR-RECEIVER LOAD PULL
Traditional LP
Verification Procedure ΔGt
complex conjugate
matched verification
Vector Receiver LP
Zin vs. Zload comparison
ΔGt
complex conjugate
matched verification
© Agilent Technologies, Inc 2012
VECTOR-RECEIVER LOAD PULL
© Agilent Technologies, Inc 2012
OUTLINE
– Background Info
– Vector-Receiver Load Pull
– Active and Hybrid-Active Load Pull
– X-Parameters and Active/Hybrid-Active Load Pull
– Pulsed-Bias Load Pull
– Conclusion
© Agilent Technologies, Inc 2012
ACTIVE & HYBRID-ACTIVE LOAD PULL
VSWR α Gamma α 1/Ω
10:1 VSWR = Γ=0.82 = 5Ω
20:1 VSWR = Γ=0.9 = 2.5Ω
Γ = a/b
X
Y
Probe
Probe
Airline
Airline
Mechanical Tuner
Gamma comes from probe
(slug) inserted into airline
Γ<1
Active Tuner
Gamma comes from signal
generator and amplifier
Γ=1 or Γ>1
© Agilent Technologies, Inc 2012
ACTIVE & HYBRID-ACTIVE LOAD PULL
Maximum Tuning Range (exaggerated for effect)
Tuner
Tuner +
Cable
Tuner + Cable + Probe
Losses of cables, probes, test fixtures reduces tuning
range and cannot be overcome using traditional load
pull methods
18
© Agilent Technologies, Inc 2012
ACTIVE & HYBRID-ACTIVE LOAD PULL
External Tuners
For Harmonic Load Pull, Traditional Load Pull systems require one mechanical tuner per
frequency per DUT side
To tune Fo, 2Fo and 3Fo at the same time requires 3 tuners (using multiplexer or cascaded
methods)
It is possible to build 3 tuners in 1 box, but it becomes 2-3x longer and 2-3x more expensive
© Agilent Technologies, Inc 2012
ACTIVE & HYBRID-ACTIVE LOAD PULL
Γ=0.99
Γ=0.99
Tuner + Cable + Probe
Gamma advantage of Active Load Pull  Losses of
cables, probes, test fixtures reduces tuning range, and
can be overcome using larger amplifiers
© Agilent Technologies, Inc 2012
ACTIVE & HYBRID-ACTIVE LOAD PULL
Active Fo Load Pull
© Agilent Technologies, Inc 2012
ACTIVE & HYBRID-ACTIVE LOAD PULL
Hybrid-Active Fo Load Pull
© Agilent Technologies, Inc 2012
ACTIVE & HYBRID-ACTIVE LOAD PULL
Active Fo, 2Fo, 3Fo Load Pull
© Agilent Technologies, Inc 2012
ACTIVE & HYBRID-ACTIVE LOAD PULL
Hybrid Active Fo, 2Fo, 3Fo Load Pull
© Agilent Technologies, Inc 2012
ACTIVE & HYBRID-ACTIVE LOAD PULL
Hybrid Active Fo, 2Fo, 3Fo Load Pull
© Agilent Technologies, Inc 2012
ACTIVE & HYBRID-ACTIVE LOAD PULL
Hybrid Active Fo, 2Fo, 3Fo Load Pull
© Agilent Technologies, Inc 2012
ACTIVE & HYBRID-ACTIVE LOAD PULL
Measured Data – Passive VS Active
Excellent Agreement
Traditional Load Pull
Active Load Pull
© Agilent Technologies, Inc 2012
ACTIVE & HYBRID-ACTIVE LOAD PULL
Passive Fo
Active 2Fo, 3Fo
Γ2Fo=0.988 @ DUT
on-wafer!
One of many configurations of ©hybrid/active
loadInc
pull
Agilent Technologies,
2012
OUTLINE
– Background Info
– Vector-Receiver Load Pull
– Active and Hybrid-Active Load Pull
– X-Parameters and Active/Hybrid-Active Load Pull
– Pulsed-Bias Load Pull
– Conclusion
© Agilent Technologies, Inc 2012
X-PARAMETERS & ACTIVE/HYBRID-ACTIVE LOAD PULL
X-Parameters
- Behavioral model
(measurement based)
- Black-box model
- Response to stimuli
- Valid under operating
conditions used to
create model
- Easily developed
Convergence
Extrapolation
Accuracy
Operating range
Physical insight
Easy modeling
process
Usability for Circuit design
© Agilent Technologies, Inc 2012
X-PARAMETERS & ACTIVE/HYBRID-ACTIVE LOAD PULL
Prior Art
Separate Disciplines
•
Load Pull
– Determine Match for a Single Device (basic amplifier design)
– Verify Large Signal Models (model validation tool)
•
X-Parameters at 50 Ohms
– Excellent data for 50 ohm matched devices, even in non-linear region
– What about non-50 ohms?
© Agilent Technologies, Inc 2012
X-PARAMETERS & ACTIVE/HYBRID-ACTIVE LOAD PULL
New Solution
Combine Load Pull and X-Parameters
1) Calibrate PNA-X NVNA
2) Vary impedances/power /bias
presented to DUT (active device,
transistor)  no change!
3) Measure Pout, Gain, Efficiency…
 no change!
4) Import X-Parameter model
into ADS and simulate circuits
© Agilent Technologies, Inc 2012
X-PARAMETERS & ACTIVE/HYBRID-ACTIVE LOAD PULL
X-Parameters with Passive Load Pull 
useful for all devices (within frequency
range of tuner)
X-Parameters with Active Load Pull  ideal
for low power devices (no tuner
needed)
X-Parameters with Hybrid-Active Load Pull
 ideal for higher power devices with
low impedance requirements
 Ideal for harmonic load pull
© Agilent Technologies, Inc 2012
X-PARAMETERS & ACTIVE/HYBRID-ACTIVE LOAD PULL
Comparison of Measured and Simulated Data
Pout
PAE
Blue – Simulated
Red - Measured
© Agilent Technologies, Inc 2012
X-PARAMETERS & ACTIVE/HYBRID-ACTIVE LOAD PULL
Comparison of Measured and Simulated Data
0.30
15
0.25
10
0.20
5
0.15
0
0.10
-5
0.05
0.0
0.2
6
0.1
4
2
0.0
0.0
0.2
0.4
0.6
time, nsec
0.8
1.0
SimulatedVoltage
MeasuredVoltage
SimulatedVoltage
MeasuredVoltage
8
0.4
0.6
0.8
1.0
0.35
15
0.30
10
0.25
5
0.20
0
0.15
-5
SimulatedCurrent
MeasuredCurrent
0.3
10
SimulatedCurrent
MeasuredCurrent
0.4
12
0.2
time, nsec
Measured and Simulated Voltage and Current Waveforms
20
0.40
Measured and Simulated Voltage and Current Waveforms
16
0.5
14
SimulatedCurrent
MeasuredCurrent
SimulatedVoltage
MeasuredVoltage
Measured and Simulated Voltage and Current Waveforms
20
0.10
0.0
0.2
0.4
0.6
0.8
1.0
time, nsec
© Agilent Technologies, Inc 2012
X-PARAMETERS & ACTIVE/HYBRID-ACTIVE LOAD PULL
Virtual 2Fo and 3Fo Load Tuning, Example 1
Load conditions
PAE vs. Available Input Power
70
gamma[3]
gamma[2]
gamma[1]
Measured_PAE
XParam_PAE
60
50
40
30
20
10
4
6
8
10
12
14
16
18
20
Pin_avail
(0.000 to 0.000)
Dynamic Load Line
Voltage and Current Waveforms at output
2.0
70
2.0
60
1.5
Measured_Vout
XParam_Vout
1.0
0.5
40
1.0
30
0.5
20
Measured_Iout
XParam_Iout
Measured_Iout
XParam_Iout
1.5
50
10
0.0
0.0
0
-0.5
-10
0
10
20
30
40
50
60
70
-10
-0.5
0.0
XParam_Vout
Measured_Vout
0.2
0.4
0.6
0.8
1.0
1.2
1.4
time, nsec
1.6
1.8
2.0
2.2
2.4
© Agilent Technologies, Inc 2012
X-PARAMETERS & ACTIVE/HYBRID-ACTIVE LOAD PULL
Virtual 2Fo and 3Fo Load Tuning, Example 2
PAE vs. Available Input Power
Load conditions
70
gamma[3]
gamma[2]
gamma[1]
Measured_PAE
XParam_PAE
60
50
40
30
20
10
(0.000 to 0.000)
4
6
8
10
12
14
16
18
20
Pin_avail
Dynamic Load Line
Voltage and Current Waveforms at output
2.0
70
2.0
60
1.5
Measured_Vout
XParam_Vout
1.0
0.5
1.0
40
30
0.5
20
0.0
Measured_Iout
XParam_Iout
Measured_Iout
XParam_Iout
1.5
50
0.0
10
-0.5
0
0
10
20
30
40
XParam_Vout
Measured_Vout
50
60
70
-0.5
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
time, nsec
1.6
1.8
2.0
2.2
2.4
© Agilent Technologies, Inc 2012
X-PARAMETERS & ACTIVE/HYBRID-ACTIVE LOAD PULL
X-Parameters combined with load pull are most useful for:
Advanced Amplifier Design – such as Doherty amplifiers, where multiple
amplifiers must be individually modeled and then designed into the same
simulation
System Engineering – X-Parameter models can be taken of amplifiers, mixers…
and modeling into an entire system to simulate overall system performance
© Agilent Technologies, Inc 2012
OUTLINE
– Background Info
– Vector-Receiver Load Pull
– Active and Hybrid-Active Load Pull
– X-Parameters and Active/Hybrid-Active Load Pull
– Pulsed-Bias Load Pull
– Conclusion
© Agilent Technologies, Inc 2012
PULSED-BIAS LOAD PULL
Prior Art
Separate Disciplines
•
Load Pull
– Performed under CW or Pulsed-CW operation conditions
– DC bias (or customer-improvised gate- or drain-pulser)
•
Pulsed IV and S-Parameters
– Used to collect IV curves under pulsed bias conditions
– Used primarily for modeling activities
© Agilent Technologies, Inc 2012
PULSED-BIAS LOAD PULL
New Solution
Combine Load Pull and Pulsed IV
© Agilent Technologies, Inc 2012
PULSED-BIAS LOAD PULL
•
Challenges
– Synchronization between RF and bias
– Sequencing between gate and drain pulsing and acquisition
– Sequencing between bias and RF generation and measurement
•
Solutions
– Common trigger between PNA-X and BILT mainframe
– Single software suite performs all sequencing and measurement of
bias and load pull parameters
© Agilent Technologies, Inc 2012
PULSED-BIAS LOAD PULL
Synchronization between gate and drain pulsing and acquisition
© Agilent Technologies, Inc 2012
PULSED-BIAS LOAD PULL
Synchronization between RF generation and measurement
© Agilent Technologies, Inc 2012
OUTLINE
– Background Info
– Vector-Receiver Load Pull
– Active and Hybrid-Active Load Pull
– X-Parameters and Active/Hybrid-Active Load Pull
– Pulsed-Bias Load Pull
– Conclusion
© Agilent Technologies, Inc 2012
CONCLUSION
Agilent, Maury and AMCAD Joint Solutions
© Agilent Technologies, Inc 2012
CONCLUSION
© Agilent Technologies, Inc 2012
CONCLUSION
For any questions, please contact your local Agilent FE or
Steve Dudkiewicz
Director, Marketing & Business Development
[email protected]
© Agilent Technologies, Inc 2012