Microwave Class-F InGaP/GaAs HBT Power Amplifier Considering up ...
The University of Electro-Communications
Microwave Class-F InGaP/GaAs HBT Power Amplifier Considering up to 7th-Order Higher Harmonic Frequencies Abstract - The first realization of a class-F InGaP/GaAs HBT amplifier considering up to 7th-order higher harmonic frequencies, operating at 1.9 GHz, is described. For a class-F amplifier design in microwave frequency ranges, not only increasing the number of treated harmonic frequencies, but also decreasing quantities of intrinsic and parasitic elements in a transistor is important. Measured PAE and collector efficiency are 78.7 % and 81.2 %, respectively, at Vcc = 4.0 V and f0 = 1.91 GHz in case circuit losses are de-embedded.
INTRODUCTION
CLASS-F LOAD CIRCUIT DESIGN
• Class-F operation for a high efficiency amplifier
• A topology of a class-F load circuit In order to obtain the voltage waveform, higher harmonic frequencies are treated to shorted or opened circuit conditions using distributed constant circuits (stubs).
Maximum efficiency of class-F PAs
A high-efficiency amplifier in the microwave region
Property of a transistor
4~6% up !!
Class-F amplifier Mathematical consideration (Fourier coefficients optimization)
n,m : order of harmonics V n=1 n=3 Im n 50% m=1 57.7% (Class-A)
m=2 m=4
n=5
n=7
n= ∞
60.3%
61.6%
63.7%
70.7%
81.7%
85.3%
87.1%
90%
75%
86.6%
90.5%
92.3%
95.5%
78.5%
90.7%
94.8%
96.7%
(Class-F)
m= ∞ (Class-B)
ZL
T2 T3 T4 T5 T6 T7 Harmonic treatment stubs Length : λ0/4m
100%
F. H. Raab, IEEE Trans. MTT, vol. 49, pp. 1162-1166, June 2001.
Efficiency for various circuit constructions of amplifiers 90
This work
80
Added RF power for output
70
(= Output power - Input power)
PAE =
60 40
ηc =
20 10 0 0.01
Harmonics Control Class-C+Push-pull Conventional
Doherty
RF Output power DC power supplies
• FR4 epoxy Thickness : 0.5 mm εr : 4.2 tanδ : 0.02 Metal thick. : 40 µm Fundamental frequency, f0 : 1.9 GHz
10
Collector layer
Circuit optimization Ideal
Ic Ic × Vce = 0
Vce Vcc
C Cbc
t
Vb C
Sub Collector layer B
HBT
Vce f0
E
Class-F load circuit
R0
Vce = Vce_DC + Vce_f0 + Odd order harmonics =
The base-collector capacitance, Cbc, is decreased by lowering collector doping density.
brought near this condition.
Ic
Shorted circuits for even order harmonics and opened circuits for odd order harmonics are added.
Load impedance, ZL [Ω]
B Emitter layer Base layer
&
Intrinsic & Parasitic break this condition. elements
T*
T2 T7
T11 T4
T3
T5 T12
400 300 200 100 0
• Low-loss resin Thickness : 0.6 mm εr : 3.6 tanδ : 0.0023 Metal thick. : 32 µm Fundamental frequency, f0 : 1.9 GHz
Load impedance, ZL
500
Device improvement
50 mm
43 mm
• Efficiency improvement
E
R0
Compensation stub n λ λ Length : 0 tan-1[–∑tan 0 ] 2π 2k k=2
• Characteristics of the fabricated class-F load circuits
ηc : Collector efficiency
0.1 1 Frequency [GHz]
Some stubs are unified.
Maximum Available Power Gain, MAG [dB]
Class-F Class-E Class-D
T*
T2 T3 T4 T5 T6 T7
R0
2
4
6 8 10 Frequency [GHz]
12
14
0 -2 -4 -6 -8 -10 -12 -14 -16 -18 -20
T3 T5 T11
T4
T7
T12
50 mm
30
T11 (λ0/4) T12 (λ0/4) : Matching for f0
(m = 2, 3, •••, n) : Order of harmonics
DC power supplies
50
T2* T3* T4* T5* T6* T7* Compensation stubs Length : λ0(2m-1)/4m
40 mm
Power added efficiency, PAE [%]
100
ZL
T11 (λ0/4) T12 (λ0/4) : Matching for f0
T2
Loss characteristic
2
4
6 8 10 12 14 Frequency [GHz] ( MAG : Transmittance of a circuit adding loss-less matching circuits.)
Simulation model (tanδ=0.0023) Low-loss resin => Circuit losses break class-F load condition at higher harmonics. FR4 epoxy
Microwave Class-F InGaP/GaAs HBT Power Amplifier Considering up to 7th-Order Higher Harmonic Frequencies Abstract - The first realization of a class-F InGaP/GaAs HBT amplifier considering up to 7th-order higher harmonic frequencies, operating at 1.9 GHz, is described. For a class-F amplifier design in microwave frequency ranges, not only increasing the number of treated harmonic frequencies, but also decreasing quantities of intrinsic and parasitic elements in a transistor is important. Measured PAE and collector efficiency are 78.7 % and 81.2 %, respectively, at Vcc = 4.0 V and f0 = 1.91 GHz in case circuit losses are de-embedded.
INTRODUCTION
CLASS-F LOAD CIRCUIT DESIGN
• Class-F operation for a high efficiency amplifier
• A topology of a class-F load circuit In order to obtain the voltage waveform, higher harmonic frequencies are treated to shorted or opened circuit conditions using distributed constant circuits (stubs).
Maximum efficiency of class-F PAs
A high-efficiency amplifier in the microwave region
Property of a transistor
4~6% up !!
Class-F amplifier Mathematical consideration (Fourier coefficients optimization)
n,m : order of harmonics V n=1 n=3 Im n 50% m=1 57.7% (Class-A)
m=2 m=4
n=5
n=7
n= ∞
60.3%
61.6%
63.7%
70.7%
81.7%
85.3%
87.1%
90%
75%
86.6%
90.5%
92.3%
95.5%
78.5%
90.7%
94.8%
96.7%
(Class-F)
m= ∞ (Class-B)
ZL
T2 T3 T4 T5 T6 T7 Harmonic treatment stubs Length : λ0/4m
100%
F. H. Raab, IEEE Trans. MTT, vol. 49, pp. 1162-1166, June 2001.
Efficiency for various circuit constructions of amplifiers 90
This work
80
Added RF power for output
70
(= Output power - Input power)
PAE =
60 40
ηc =
20 10 0 0.01
Harmonics Control Class-C+Push-pull Conventional
Doherty
RF Output power DC power supplies
• FR4 epoxy Thickness : 0.5 mm εr : 4.2 tanδ : 0.02 Metal thick. : 40 µm Fundamental frequency, f0 : 1.9 GHz
10
Collector layer
Circuit optimization Ideal
Ic Ic × Vce = 0
Vce Vcc
C Cbc
t
Vb C
Sub Collector layer B
HBT
Vce f0
E
Class-F load circuit
R0
Vce = Vce_DC + Vce_f0 + Odd order harmonics =
The base-collector capacitance, Cbc, is decreased by lowering collector doping density.
brought near this condition.
Ic
Shorted circuits for even order harmonics and opened circuits for odd order harmonics are added.
Load impedance, ZL [Ω]
B Emitter layer Base layer
&
Intrinsic & Parasitic break this condition. elements
T*
T2 T7
T11 T4
T3
T5 T12
400 300 200 100 0
• Low-loss resin Thickness : 0.6 mm εr : 3.6 tanδ : 0.0023 Metal thick. : 32 µm Fundamental frequency, f0 : 1.9 GHz
Load impedance, ZL
500
Device improvement
50 mm
43 mm
• Efficiency improvement
E
R0
Compensation stub n λ λ Length : 0 tan-1[–∑tan 0 ] 2π 2k k=2
• Characteristics of the fabricated class-F load circuits
ηc : Collector efficiency
0.1 1 Frequency [GHz]
Some stubs are unified.
Maximum Available Power Gain, MAG [dB]
Class-F Class-E Class-D
T*
T2 T3 T4 T5 T6 T7
R0
2
4
6 8 10 Frequency [GHz]
12
14
0 -2 -4 -6 -8 -10 -12 -14 -16 -18 -20
T3 T5 T11
T4
T7
T12
50 mm
30
T11 (λ0/4) T12 (λ0/4) : Matching for f0
(m = 2, 3, •••, n) : Order of harmonics
DC power supplies
50
T2* T3* T4* T5* T6* T7* Compensation stubs Length : λ0(2m-1)/4m
40 mm
Power added efficiency, PAE [%]
100
ZL
T11 (λ0/4) T12 (λ0/4) : Matching for f0
T2
Loss characteristic
2
4
6 8 10 12 14 Frequency [GHz] ( MAG : Transmittance of a circuit adding loss-less matching circuits.)
Simulation model (tanδ=0.0023) Low-loss resin => Circuit losses break class-F load condition at higher harmonics. FR4 epoxy
