RF and Microwave Amplifier
Power Added Efficiency,
Fact and Fiction
Dr. Dominic FitzPatrick
Principal Consultant, PoweRFul Microwave
www.powerful-microwave.co.uk
RF and Microwave Amplifier Power Added Efficiency, Fact and Fiction
2013, November 6th
1
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RF and Microwave Amplifier Power
Added Efficiency, Fact and Fiction
Dr. Dominic FitzPatrick
Principal Consultant,
PoweRFul Microwave
www.powerful-microwave.co.uk
RF and Microwave Amplifier Power Added Efficiency, Fact and Fiction
2013, November 6th
10
Power Added Efficiency
– The Basics
Why is it important?
 Smaller power supply, less current drawn
 Smaller, lighter DC supply cables
 Less heat generated
 Cooler running, higher reliability
 Lower weight,
 The higher the performance.
But, it doesn’t come for free; and it becomes harder to improve
the efficiency the higher we go, i.e. 10% increase from 30-40% 
from 60-70%  from 70-80% 
RF and Microwave Amplifier Power Added Efficiency, Fact and Fiction
2013, November 6th
11
Power Added Efficiency
– The Basics
What does the equation mean?
 Note:- RFPIN means ‘IN’ to the device, not the source
power, i.e. better input match higher PAE?
 Higher gain, higher PAE – GaN advantage!
Don’t get confused with Drain Efficiency.
Is DE actually a useful measure without including the
impact of gain?
RF and Microwave Amplifier Power Added Efficiency, Fact and Fiction
2013, November 6th
12
Input & PAE
With the isolator no power is reflected
back and so RFPIN = source power.
Higher RFPIN lower PAE
RF and Microwave Amplifier Power Added Efficiency, Fact and Fiction
2013, November 6th
13
Input & PAE
Without the isolator the power
reflected by the device is subtracted
from source power to give RFPIN.
With the isolator no power is reflected
back and so RFPIN = source power.
Higher RFPIN lower PAE
RF and Microwave Amplifier Power Added Efficiency, Fact and Fiction
2013, November 6th
14
Power Transfer
Swp Max
3GHz
2.
0
6
0.
0 .8
1.0
Foronmathematical
proofand
of the
contours
see
We normally look at device impedances
the Smith Chart,
if we
consider
the
“RFalso
Power
case of the maximum output load Ropt,Cripps,
there are
two Amplifiers
load whichfor
willWireless
deliver half
the power (3dB down), Ropt/2 and Ropt Communications”.
x2
3dB Output
In practice this would be tedious to do for every
PORT
Power
Contour
Load Matchdrive level, etc. Also it
frequency, bias setting,
P=2
GPROBE
assumes ideal DC-IV Curves in practice
Z=50 Ohm
ID=XF1
however:
Rsense=0.0001 Ohm
3I
0.
4
1
p2
0
4.
2500
2
5 .0
0 .2
10.0
4.0
5.0
3.0
2.0
1.0
0.8
0.6
0.4
0.2
0
Drain Current (mA)
p6
p16
p15
p14
p13
p12
p11
p10
p9
p8
p7
p6
p5
p4
p3
p2
p1
1500
1000
4
500
0.
-1.0
- 0. 8
-0
.6
p1
p1
150
Drain Voltage (V)
RF and Microwave Amplifier Power Added Efficiency, Fact and Fiction
p9
p1
Swp Min
1GHz
100
50
p8
p1
.0
-2
-
GAM1_GP(1,3,2,50,0)
Device Output
0
GAM2_GP(4,3,2,50,0)
Device Output 0
p7
p1
-3
.0
PORT
P=3
Z=50 Ohm
2
p5
-4
.0
- 0.
p4
1 0. 0
0
PORT
P=1
Z=30 Ohm
6V
2072 mA
2000
p3
- 5.
2
4 V
IVCurve() (mA)
DC_IV
- 10 . 0
PORT
P=4
Z=15 Ohm
1
p1
.0
3
DC_IV Curves
2013, November 6th
p1
p1
16
Power Transfer with
a Nonlinear Model
Tuner steps over
impedance grid.
Simulation at each load
point produces
performance contours, in
this case of constant PAE
(red) and Output Power
(blue).
RF and Microwave Amplifier Power Added Efficiency, Fact and Fiction
2013, November 6th
17
Bias
Not going to cover the theory of different classes of operation
here
→ Already comprehensively covered such as by Prof. Steve
Cripps.
But we will look at the effects of bias and remember that it is
another variable open to use.
Available (Power) Gain at Vp
(bold), Idq=200mA and Idq=800mA
RF and Microwave Amplifier Power Added Efficiency, Fact and Fiction
2013, November 6th
18
Bias
Not going to cover the theory of different classes of operation
here
→ Already comprehensively covered such as by Prof. Steve
Cripps.
But we will look at the effects of bias and remember that it is
another variable open to use.
Increase
Thermal Optimization of GaN
HEMT
Thermal
Transistor Power Amplifiers Using
New SelfResistance
heating Large Signal Model, Cree-App-Noteto 8°C/W
006
RF and Microwave Amplifier Power Added Efficiency, Fact and Fiction
2013, November 6th
19
Tuners
– Be Wary
LTUNER – Nice and simple, but what impedance does it
present at other frequencies?
LTUNER – All frequencies are terminated with the same
load impedance, in this case |GM| /_GA°.
RF and Microwave Amplifier Power Added Efficiency, Fact and Fiction
2013, November 6th
20
Tuners
– Be Wary
LTUNER – Nice and simple, but what impedance does it
present at other frequencies?
LTUNER
LPTUNER
––
AllDefine
frequencies
frequencies
are terminated
and their with
terminations,
the same
load
but ifimpedance.
you don’t define them they default.
Here we have defined 0.5, 1 &
2GHz but the other frequencies
2.5, 3, 3.5 and 4GHz also have
defaulted to this load.
RF and Microwave Amplifier Power Added Efficiency, Fact and Fiction
2013, November 6th
21
Tuners
– Be Wary
LTUNER – Nice and simple, but what impedance does it
present at other frequencies?
LTUNER
LPTUNER
––
AllDefine
frequencies
frequencies
are terminated
and their with
terminations,
the same
load
but ifimpedance.
you don’t define them they default.
Now we have defined
different
impedances
to
some of the frequencies, 3 &
4GHz are terminated in 50Ω
RF and Microwave Amplifier Power Added Efficiency, Fact and Fiction
2013, November 6th
22
Tuners
– Be Wary
LTUNER – Nice and simple, but what impedance does it
present at other frequencies?
LTUNER
HBTUNER
– All
– Takes
frequencies
care ofare
theterminated
harmonic frequencies
with the same
load
for you.
impedance.
Takes care of the
harmonic
terminations of
the defined
frequency.
RF and Microwave Amplifier Power Added Efficiency, Fact and Fiction
2013, November 6th
23
Tuners
– Be Wary
LTUNER – Nice and simple, but what impedance does it
present at other frequencies?
LTUNER
HBTUNER
– All
– But….
frequencies
Be aware
are of
terminated
what happens
with the
at other
same
load
frequencies
impedance.
and their terminations.
Harmonic impedance has
an impact on device
performance, so know
where you have put yours!
RF and Microwave Amplifier Power Added Efficiency, Fact and Fiction
2013, November 6th
24
Load Pull Set Up
Difference between using LTUNER and HBTUNER with
harmonics terminated in 50Ω.
Load Pull with LTUNER
Load Pull with HBTUNER
Small impact on Pout – Significant on PAE
RF and Microwave Amplifier Power Added Efficiency, Fact and Fiction
2013, November 6th
25
Load Pull Set Up
We use Load Pull so that we can visualise the tradeoffs between parameters, typically PAE and Pout.
Load Pull Check List
1.
2.
3.
Harmonic terminations –
use HBTUNER for
accurate/consistent results.
Input Power level, check
that you are using the
optimum drive level by
conducting a power sweep.
Bias/Class of operation.
RF and Microwave Amplifier Power Added Efficiency, Fact and Fiction
2013, November 6th
26
Input Match Effects
Why does the input match
change?
1. Intrinsic capacitance
2. Channel resistance
3. Load match
Intrinsic Cree GaN HEMT Models allow more accurate
waveform engineered PA designs
Ray Pengelly and Bill Pribble, Cree RF Products
ARMMS, April, 2013
RF and Microwave Amplifier Power Added Efficiency, Fact and Fiction
2013, November 6th
27
Effect of Load on
Input Match
33dBm
RF and Microwave Amplifier Power Added Efficiency, Fact and Fiction
2013, November 6th
28
Effect of Load on
Input Match
33dBm
RF and Microwave Amplifier Power Added Efficiency, Fact and Fiction
2013, November 6th
29
Effect of Load
on Input Match
33dBm
RF and Microwave Amplifier Power Added Efficiency, Fact and Fiction
2013, November 6th
30
Input Power
with Frequency
For wideband designs you have to
consider input power vs. frequency.
Output power stays ~ constant with
frequency.
So, to a first order input power needs to
increase at this rate.
Let’s take a look 
6dB/octave slope
RF and Microwave Amplifier Power Added Efficiency, Fact and Fiction
2013, November 6th
31
Input Power
with Frequency
Note:
1. Input power variation for optimum PAE.
2. The maximum Output Power is constant.
3. The intrinsic gain rolls off ~5dB/octave. Output
matching recovers some but not all.
4. There is no input matching yet, this shows the
need for a positive sloped input power match
to achieve the maximum PAE across a wide
bandwidth.
Freq.
(GHz)
Pin
(dBm)
Max.
PAE
(%)
Load
Pout
(dBm)
Gain
(dB)
Max.
Pout
(dBm)
1
28
72
0.27/112°
40.5
12.7
42.5
0.43/174°
2
33
70
0.42/145°
41.4
8.4
42.5
0.44/178°
3
36
69
0.49/163°
41.7
5.7
42.5
0.47/-174°
4
38
67
0.57/175°
41.5
3.5
42.5
0.46/-161°
RF and Microwave Amplifier Power Added Efficiency, Fact and Fiction
Load
2013, November 6th
32
Choosing
the Optimum Load
For wideband designs you have to
consider input power vs. frequency.
Output power stays ~ constant with
frequency.
So, to a first order input power needs to
increase at this rate.
Let’s take a look 
Be aware that the maximum load
point may not be the “optimum”
Green ‘hour-glass symbol shows
load for power sweep.
By observing swept input power
performance as you tune the load
you can adjust for the best
compromise performance between
Power and PAE.
RF and Microwave Amplifier Power Added Efficiency, Fact and Fiction
2013, November 6th
33
Returning to
the Optimum Loads
Looking at a simple device
output equivalent circuit,
including some package deembedding:
The equivalent load
resistance increases from
23Ω for the optimum power
loads to 41Ω for the
optimum PAE loads – which
agrees with theory ☺
Device
RF and Microwave Amplifier Power Added Efficiency, Fact and Fiction
Package
2013, November 6th
34
Load Line Theory
Class A/B Bias
Point
Class A Bias
Point
Theory Optimum Power load = 2x(VD-VK)/IDS = 20Ω
RF and Microwave Amplifier Power Added Efficiency, Fact and Fiction
2013, November 6th
35
Load Line Simulation
Addition of internal nodes to
model allows direct observation As we increase drive Dynamic (RF) load
line interacts with limits of the DC-IV
of drain waveforms.
envelope.
RF and Microwave Amplifier Power Added Efficiency, Fact and Fiction
2013, November 6th
36
Load Line Simulation
Addition of internal nodes to
model allows direct observation
of drain waveforms.
Or change load impedance
RF and Microwave Amplifier Power Added Efficiency, Fact and Fiction
2013, November 6th
37
Harmonic
Terminations
A great deal of research has gone into the design of high PAE modes
class E, F & J for example, and the importance of harmonic terminations.
Using these tools we can see their impact. Fundamental Load Pull is
conducted with the harmonics
terminated in 50Ω.
Swept Input Power
PAE (R)
100
Gain (L)
m2
Pout (L, dBm)
m1
40
80
30
60
20
40
m3
10
PAE (% )
Gain (dB) and Output Pow er (dBm)
50
20
m1: 27 dBm
74.6
m2: 27 dBm
m3: 27 dBm
43.9 dBm
16.9 dB
0
0
10
15
20
25
30
Input Power (dBm)
RF and Microwave Amplifier Power Added Efficiency, Fact and Fiction
2013, November 6th
38
Harmonic
Terminations
Keeping the Fundamental at the optimum PAE impedance a 2nd Harmonic Load
Pull is conducted with the 3r harmonic terminated in 50Ω.
We are simulating across
the majority of the real
impedance plane. Of
interest is not just the
optima but also the minima
– places to avoid!
RF and Microwave Amplifier Power Added Efficiency, Fact and Fiction
2013, November 6th
39
Harmonic
Terminations
Keeping the Fundamental & now 2nd at their optimum PAE impedances a 3rd
Harmonic Load Pull is conducted.
We now have almost half
the impedance plane where
the effect is minimal
however we again see
where to avoid!.
Swept Input Power
PAE (R)
100
Gain (L)
m2
m1
Pout (L, dBm)
40
80
30
60
m3
20
PAE (% )
Gain (dB) and Output Pow er (dBm)
50
40
10
20
m1: 27 dBm
82.8
m2: 27 dBm
m3: 27 dBm
44.4 dBm
17.4 dB
0
0
10
15
20
25
30
Input Power (dBm)
RF and Microwave Amplifier Power Added Efficiency, Fact and Fiction
2013, November 6th
40
Harmonic
Terminations
Now we have all our terminations optimised, or have we? Re-do the
fundamental load pull with the optimum PAE harmonic terminations CG Plane Waveforms
80
The fundamental load has
moved and3.5we have increased
the maximum PAE.
3
R F V o lta g e ( V )
60
p1
2.5
50
2
40
1.5
30
1
20
0.5
10
R F C urrent (m A)
70
0
p2
0
-0.5
0
Vtime(V_METER.VM3,1)[1,18] (L, V)
Swept power.AP_HB
0.2
0.4
Itime(I_METER.AMP2,1)[1,18] (R, A)
Swept power.AP_HB
0.6
0.8
Time (ns)
RF and Microwave Amplifier Power Added Efficiency, Fact and Fiction
1
p1: Freq = 2 GHz p2: Freq = 2 GHz
Pwr = 27 dBm
Pwr = 27 dBm
2013, November 6th
41
Harmonic
Terminations
No significant change at
30% PAE and 40dBm
Pout, but increase in the
peaks and consequently a
wider impedance range
included in the 70% PAE
and 45dBm Pout, indeed
these two regions now
have a significant overlap.
RF and Microwave Amplifier Power Added Efficiency, Fact and Fiction
2013, November 6th
42
Dynamic Load Line &
Harmonic Terminations
DC-IV
4.5
4.5
IVCurve() (A)
IVCurve()
DCIV
Drain
(mA)
Current(mA)
DrainCurrent
p3: Vstep = -3.8 V
p4: Vstep = -3.7 V
p5: Vstep = -3.6 V
p6: Vstep = -3.5 V
p7:
p7: Vstep
Vstep =
= -3.4
-3.4 V
V
p8:
p8: Vstep
Vstep =
= -3.3
-3.3 V
V
p9:
p9: Vstep
Vstep =
= -3.2
-3.2 V
V
Notice that we
are avoiding
high current
swings in
favour of
higher voltage
swings.
p12:
p12: Vstep
Vstep =
= -2.9
-2.9 V
V
p13:
p15: Vstep
Vstep =
= -2.6
-2.6 V
V
p13: Vstep
Vstep =
= -2.8
-2.8 V
V p14:
p14: Vstep
Vstep =
= -2.7
-2.7 V
V p15:
p16: Vstep = -2.5 V p17: Vstep = -2.4 V p18: Vstep = -2.3 V
p16: Vstep = -2.5 V p17: Vstep = -2.4 V p18: Vstep = -2.3 V
p19: Vstep = -2.2 V p20: Vstep = -2.1 V p21: Vstep = -2 V
p19: Vstep = -2.2 V p20: Vstep = -2.1 V p21: Vstep = -2 V
28 V
V
28
0.4222
A
0.4222 A
p22: Vstep = -1.9 V p23: Vstep = -1.8 V p24: Vstep = -1.7 V
p22: Vstep = -1.9 V p23: Vstep = -1.8 V p24: Vstep = -1.7 V
2.5
2.5
2.5
p25: Vstep = -1.6 V p26: Vstep = -1.5 V p27: Vstep = -1.4 V
p25: Vstep = -1.6 V p26: Vstep = -1.5 V p27: Vstep = -1.4 V
p41
p40
p39
p41
p41
p38
p40
p40
p37
p39
p39
p36
p38
p38
p35
p37
p37
p34
p36
p36
p33
p35
p35
p32
p34
p34
p31
p33
p33
p30
p32
p32
p31
p31
p29
p30
p30
p28
p29
p29
p27
p28
p28
p26
p27
p27
p25
p26
p26
p24
p25
p25
p23
p24
p24
p22
p23
p23
p21
p22
p22
p20
p21
p21
p19
p20
p20
p18
p19
p19
p17
p18
p18
p16
p17
p17
p15
p16
p16
p14
p15
p15
p13
p14
p14
p12
p13
p13
p11
p12
p12
p10
p9
p11
p11
p8
p7
p4
p5
p6
p2
p3
p1
p10
p10
p9
p9
p8
p8
p7
p7
p4
p5
p6
p2
p3
p1
p4
p5
p6
p2
p3
p1
1.5
1.5
1.5
0.5
0.5
0.5
-0.5
-0.5
-0.5
p2: Vstep = -3.9 V
p10:
p10: Vstep
Vstep =
= -3.1
-3.1 V
V p11:
p11: Vstep
Vstep =
= -3
-3 V
V
IVDLL(V_METER.VM3,I_METER.AMP2)[1,T]
(A)
IVDLL(V_METER.VM3,I_METER.AMP2)[1,T] (A)
IVDLL(V_METER.VM3,I_METER.AMP2)[1,T]
Swept
power.AP_HB
Swept power.AP_HB
power.AP_HB
Swept
3.5
3.5
3.5
p1: Vstep = -4 V
p62
p62
p62
0
00
10
10
10
20
20
20
30
30
30
40
40
50
60
50
60
Voltage (V)
Voltage (V)
p28: Vstep = -1.3 V p29: Vstep = -1.2 V p30: Vstep = -1.1 V
p28: Vstep = -1.3 V p29: Vstep = -1.2 V p30: Vstep = -1.1 V
p54
p55
p56
p57
p58
p59
p60
p52
p53
p49
p50
p61
p51
p48
p47
p46
p45
p44
p43
p42
p54
p55
p56
p57
p58
p59
p60
p52
p53
p49
p50
p61
p51
p48
p47
p46
p45
p44
p43
p42
p31: Vstep = -1 V
p31: Vstep = -1 V
p32: Vstep = -0.9 V p33: Vstep = -0.8 V
p32: Vstep = -0.9 V p33: Vstep = -0.8 V
p34: Vstep = -0.7 V p35: Vstep = -0.6 V p36: Vstep = -0.5 V
p34: Vstep = -0.7 V p35: Vstep = -0.6 V p36: Vstep = -0.5 V
p37: Vstep = -0.4 V p38: Vstep = -0.3 V p39: Vstep = -0.2 V
p37: Vstep = -0.4 V p38: Vstep = -0.3 V p39: Vstep = -0.2 V
83.03 V
-0.04256 A
70
70
80
80
90
90
p40: Vstep = -0.1 V p41: Vstep = 0 V
p40: Vstep = -0.1 V p41: Vstep = 0 V
p42: Vstep = 0.1 V
p42: Vstep = 0.1 V
p43: Vstep = 0.2 V
p43: Vstep = 0.2 V
p44: Vstep = 0.3 V
p44: Vstep = 0.3 V
p45: Vstep = 0.4 V
p45: Vstep = 0.4 V
p46: Vstep = 0.5 V
p46: Vstep = 0.5 V
p47: Vstep = 0.6 V
p47: Vstep = 0.6 V
p48: Vstep = 0.7 V
p48: Vstep = 0.7 V
p49: Vstep = 0.8 V
p50: Vstep = 0.9 V
p51: Vstep = 1 V
p49: Vstep = 0.8 V
p50: Vstep = 0.9 V
p51: Vstep = 1 V
p52: Vstep = 1.1 V
p53: Vstep = 1.2 V
p54: Vstep = 1.3 V
p52: Vstep = 1.1 V
p53: Vstep = 1.2 V
p54: Vstep = 1.3 V
p55: Vstep = 1.4 V
p56: Vstep = 1.5 V
p57: Vstep = 1.6 V
p58: Vstep = 1.7 V
p56: Vstep = 1.5 V
p59: Vstep = 1.8 V
p57: Vstep = 1.6 V
p60: Vstep = 1.9 V
p59: Vstep = 1.8 V
p62: Freq = 2 GHz
Pwr = 27 dBm
p62: Freq = 2 GHz
Pwr = 27 dBm
p60: Vstep = 1.9 V
100 p55: Vstep = 1.4 V
100
p58: Vstep = 1.7 V
p61: Vstep = 2 V
p61: Vstep = 2 V
Fundamental,
2nd2,nd&Optimum,
3rd Optimum.
Note
Fundamental &
Optimum,
2nd & 3rd in
50Ωnearly 3x Drain Voltage Swing.
RF and Microwave Amplifier Power Added Efficiency, Fact and Fiction
2013, November 6th
43
Optimum Load Design
is a Cyclical Process
Harmonic Load Pull Steps:
Remember it is not only
1. Optimum Fundamental Drive
about finding the
Power.
optimums - you also need
2. Optimum Fundamental Load Check (1) is still true.
to know where to avoid!
3. 2nd Harmonic LP – Check (1) & (2)
We can’t always use the optimum
are still true.
4. 3rd Harmonic LP –Check (1), (2) harmonic termination. If we are
and (3) are still true.
doing wide bandwidth designs
5. Go on to next frequency!
the harmonic falls in band.
RF and Microwave Amplifier Power Added Efficiency, Fact and Fiction
2013, November 6th
44
Broadband Matching:Insertion Loss and Match
Load Pull gives the performance
before any matching circuit Broadband Matching circuitry seeks to
resolve two key problems:
i.
ii.
How to maximise bandwidth with a
minimum Reflection Coefficient, Γ.
How to minimise the number of
matching elements, N, for a given
bandwidth, (typically loss α N).
Don’t confuse LT with insertion loss
that has got to be included too!
Γ
0.1 0.18 0.2 0.25 0.35 0.4
0.5 0.71
RL (dB)
20
15
14
12
9
8
6
3
LT (dB)
0.04 0.14 0.18 0.28 0.58 0.76 1.25 3.0
VSWR
1.22 1.43 1.50 1.67 2.1 2.33 3.00 5.85
Γ, Return Loss, Mismatch (Transmission) Loss and VSWR.
RF and Microwave Amplifier Power Added Efficiency, Fact and Fiction
0.8
1.9
4.44
9.00
2013, November 6th
45
Current Approaches
and Performance
RF and Microwave Amplifier Power Added Efficiency, Fact and Fiction
2013, November 6th
46
Current Approaches
and Performance
RF and Microwave Amplifier Power Added Efficiency, Fact and Fiction
2013, November 6th
47
Current Approaches
and Performance
Technology
cmos
Class
E
GaAs pHEMT
GaN HEMT
GaN HEMT
GaN HEMT
A/B
F
F-1
F-1 PushPull
GaAs pHEMT J
GaAs HVHBT
LDMOS
GaN HEMT
GaN HEMT
GaN HEMT
Doherty
B 2HT
B?
VM D
Doherty
GaN HEMT
GaN HEMT
GaN HEMT
LDMOS
LDMOS
LDMOS
F
A/B 2HT
J
B
B
B
Fmin Fmax Eff.
GHz GHz
%
Pout Dev.Power Year Reference
2
3 40.2 PAE 0.36
NS 2013 Broadband and High-Efficiency Power Amplifier that Integrates CMOS and IPD Technology
8.5
5.65
3.27
2.5
12.5
5.7
3.3
2.55
8
11
2.1
0.9
0.01
0.05
3.5
40
76
74
75
PAE
PAE
PAE
DE
5
4
6.7
18.6
8x 0.8
0.96mm
10
2x 10
2013
2012
2010
2010
Design Procedure 4 Hi-Eff and Compact-Size 5–10W MMIC PAs in GaAs pHEMT Tech.
Ultra High Efficiency Microwave Power Amplifier for Wireless Power Transmission
First-Pass Design of High Efficiency Power Amplifiers using Accurate Large Signal Models
First-Pass Design of High Efficiency Power Amplifiers using Accurate Large Signal Models
63 DE
0.45
0.6 2011 GaAs X-Band Hi Eff (>65%) Broadband (>30%) Amp MMIC based on Class B to J Continuum
2.15
0.95
0.5
0.5
3.55
57
73
43
63
59
DE
DE
PAE
DE
PAE
74
10
100
20
6.5
2x 120
30
4x 45
10 x2
6 x2
2010
2010
2009
2011
2013
Doherty Power Amp using 2nd Gen. HVHBT Technology for Hi Eff Basestation Applications
Lumped-element Output Networks for High-efficiency Power Amplifiers
Design of a 100Watt High-Efficiency Power Amplifier for the 10-500MHz Band
Development of a WB Highly Efficient GaN VoltageModeClassD VHFUHF Power Amplifier
A LinearandEfficientDohertyPAat3p5GHz
0.55
1.1
1.9
2.9
1.4
2.7
0.5 0.505
1.3 1.305
0.085 0.115
65
60
50
66
45
73
DE
10
DE
31.6
PAE
10
PAE
680
PAE 10000
PAE 1200
10
45
10
1000
160
1200
2011
2010
2009
2012
2012
2012
A Novel Hi Eff BB Continuous ClassF RFPA Delivering 74% Average Eff for an Octave BW
Design of a BB Highly Efficient 45W GaN PA via Simplified Real Freq Technique
Methodology4RealizingHiEffClassJinaLinearBroadbandPA
Developments of High CW RF PowerSSAatSoleil
1st Experience At Elbe with new 1.3GHz CWRF System Based on 10kWSSA
Own work
Recommend Cree Website for extensive list of technical papers:
http://www.cree.com/RF/Document-Library
RF and Microwave Amplifier Power Added Efficiency, Fact and Fiction
2013, November 6th
48
Topology Counts
Balanced Approach:
A number of the papers just referenced used balanced amplifiers to achieve
high power and efficiency, particularly the very high power LDMOS. Two
GaN exceptions were the broad band “Design of a 100Watt High-Efficiency
Power Amplifier for the 10-500MHz Band” (left) and the 2.5GHz “First-Pass
Design of High Efficiency Power Amplifiers using Accurate Large Signal
Models” (right). Interesting both use devices capable of 2x the output power
they achieve.
RF and Microwave Amplifier Power Added Efficiency, Fact and Fiction
2013, November 6th
49
Topology Counts
Doherty Approach:
Uses parallel devices to increase efficiency
at back off as graph from “Doherty Power
Amplifiers using 2nd Generation HVHBT
Technology for High Efficiency Basestation
Applications”.
Envelope Tracking
Astrium 200W GaN demonstrator performance
using drain bias adjustment for increased PAE.
RF and Microwave Amplifier Power Added Efficiency, Fact and Fiction
2013, November 6th
50
Summary
a)
b)
c)
d)
Device self-heating model.
Input match.
Wide Band designs ‘tapered’ input drive level.
Observe the Current Generator Plane waveforms –
6 port device model.
e) Don’t forget mismatch and insertion losses of
output matching circuit.
f) Harmonic terminations - they can both enhance
and degrade performance.
g) Models aren’t valid over an infinite range.
RF and Microwave Amplifier Power Added Efficiency, Fact and Fiction
2013, November 6th
51
Questions?
Thank You!
Sponsored by:
www.awrcorp.com
www.cree.com
PoweRFul Microwave
www.powerful-microwave.co.uk
RF and Microwave Amplifier Power Added Efficiency, Fact and Fiction
2013, November 6th
52