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JOURNAL OF ELECTRONIC SCIENCE AND TECHNOLOGY, VOL. 9, NO. 1, MARCH 2011
Design of 35 GHz 1 Watt GaAs pHEMT
Power Amplifier MMIC
Bo Hong and Wen-Bin Dou
Abstract⎯By using 0.15 μm GaAs pHEMT
(pseudomorphic high electron mobility transistor)
technology, a design of millimeter wave power amplifier
microwave monolithic integrated circuit (MMIC) is
presented. With careful optimization on circuit structure,
this two-stage power amplifier achieves a simulated gain
of 15.5 dB with fluctuation of 1 dB from 33 GHz to 37
GHz. A simulated output power of more than 30 dBm in
saturation can be drawn from 3 W DC supply with
maximum power added efficiency (PAE) of 26%.
Rigorous electromagnetic simulation is performed to
make sure the simulation results are credible. The whole
chip area is 3.99 mm2 including all bond pads.
Index Terms⎯GaAs pHEMT (pseudomorphic high
electron mobility transistor), millimeter wave,
microwave monolithic integrated circuit, power added
efficiency, power amplifier.
1. Introduction
As an important resource, frequency of millimeter wave
has been widely developed in applications, such as
automatic radar, satellite communication, and defense.
However, circuits working in millimeter wave band are
hard to realize due to the complexity nature induced by
high frequency. As one of the most important components
in a transmission system, millimeter wave power amplifiers
have been researched for a long time, and many reports
have been presented to investigate and demonstrate the
amplifiers in recent years[1]-[5].
Because of the development of microwave monolithic
integrated circuit (MMIC) fabrication technology, there are
variety of fabrication processes capable of supporting the
millimeter wave applications today. Among them, GaAs
pHEMT (pseudomorphic high electron mobility transistor)
is the widest choice for millimeter wave high power
Manuscript received May 10, 2010; revised December 26, 2010. This
work was supported by the Innovation Fund of State Key Lab of
Millimeter Waves.
B. Hong and W.-B. Dou are with the State Key Laboratory of
Millimeter Waves, Southeast University, Nanjing 210096, China (e-mail:
hongbo-gg@live.cn and wbdou@seu.edu.cn).
Color versions of one or more of the figures in this paper are available
online at http://www.intl-jest.com/.
Digital Object Identifier: 10.3969/j.issn.1674-862X.2011.01.015
amplifier due to its high speed and relatively high
breakdown voltage.
The proposed design is a power amplifier working at 35
GHz with a bandwidth of approximate 4 GHz. GaAs
pHEMT processes with the feature size of 0.25 μm and 0.15
μm have been utilized in this band successfully and
reported in former articles[1]-[5]. 0.25 μm technology is more
robust resulting in high yield[1], however, 0.15 μm
technology can deliver better frequency response in
millimeter wave band at the expense of higher cost and
slightly lower breakdown voltage. Finally, 0.15 μm GaAs
pHEMT technology is chosen to commence this design.
2. Circuit Design
To reach the goal of output power as well as gain
requirement, the power amplifier is designed as consisting
of two stages, with four 4 μm×100 μm devices connected in
parallel used as an output stage and driven by two 4
μm×100 μm devices. The simple schematic of this power
amplifier is shown in Fig. 1.
The output matching network is designed for obtaining
the maximum output power and efficiency with low-pass
configuration to limit the level of higher order frequencies.
Because there is no condition for load pull hardware test,
the optimum load impedance required for the maximum
output power of one 4 μm×100 μm device is derived by
load pull simulation using advanced design system (ADS).
By calculation using Cripps’ law[6] and load pull simulation,
four of them combined in parallel can be expected to
deliver an output power of 30 dBm.
The inter-stage matching network is designed for
drawing enough power from drive stage to push the output
stage into saturation. The flatness of the whole gain is also
considered. The input matching network is simply designed
for maximizing the gain following the conjugate matching
principle. Both the inter-stage matching network and the
input matching network adopt high-pass configuration to
limit the low-frequency gain in order to make the whole
circuit more stable.
Because the chip area is the main fact that dominates
the chip cost, it is important to confine the area of matching
network without degradation on performance. For this
reason, metal-insulator-metal capacitors and micro shunt
transmission line inductors are used as matching elements
along with transmission lines to construct all the matching
networks. Traditional power divider or combiner, like
Wilkinson or Lange coupler, should be discarded due to
their large area occupation and hardness for DC supply[7].
All of the passive structures are simulated using a 2.5D
electromagnetic simulation tool.
The K-factor and normalized determinant function
(NDF)[8],[9] are tested over the whole band from DC to 40
GHz to keep the stability. Considering the existing of bond
wire induction, some necessary compromise is made on the
matching network. To protect the pads from electro-static
discharge (ESD) and surge voltage, all the gate bias bond
pads are shunted by large diodes. The layout of the whole
chip is shown in Fig. 2.
3. Simulation Results
The performances of this MMIC power amplifier were
simulated using the ADS simulation tool, All the transistors
were biased under the condition of Vds=5.0 V and Id=100
mA, which means 3 W power consumption in total.
The small signal performances are shown in Fig. 3. The
simulation result shows a flat gain of 15.5 dB with
fluctuation of approximate 1 dB ranging from 33 GHz to 37
GHz performed by this power amplifier. The curve of the
output power performances versus frequency including the
output power at 1 dB gain compressed point (P1dB), saturate
output power (Psat), and power added efficiency (PAE) are
shown on Fig. 4 and Fig. 5.
Gain and return losses (dB)
JOURNAL OF ELECTRONIC SCIENCE AND TECHNOLOGY, VOL. 9, NO. 1, MARCH 2011
20
15
10
5
0
Frequency(GHz)
−5
−10
−15
−20
−25
32
33
34
35
36
Input power (dBm)
37
38
Fig. 3. Small signal gain S21 (triangle symbol line) and input
return loss S11 (squared symbol line), output return loss S22 (circle
symbol line).
P1dB & Psat (dBm)
82
30.4
30.3
30.2
30.1
30.0
29.9
29.8
29.7
29.6
29.5
29.4
29.3
P1dB
Psat
33
34
35
36
Frequency (GHz)
37
Fig. 4. Curve of output power performance versus frequency.
PAE
28.0
PAE (%)
27.5
27.0
26.5
26.0
25.5
25.0
Fig. 1. Simple schematic of the power amplifier without bias
inductor,
capacitor,
transistor, and
networks (
port).
Fig. 2. Layout of the whole power amplifier MMIC (chip size:
2.66 mm×1.5 mm).
33
34
35
36
Frequency (GHz)
37
Fig. 5. Curve of PAE versus frequency.
Fig. 6. Photo of TGA-1171-SCC (chip size: 2.863 mm×2.74 mm).
83
HONG et al.: Design of 35 GHz 1 Watt GaAs pHEMT Power Amplifier MMIC
A comparison between this design and some typical
works of the same category is made as shown in Table 1. It
can be seen that this task has obvious advantage on
efficiency and output power with a relatively small chip
area. Two commercial products of CHA 5296 from United
Monolithic Semiconductors and TGA-1171-SCC from
Triquint are quoted here for comparison in Table 1.
Here this paper gives the detailed performance of
TGA-1171-SCC for comparison. The photo of the chip is
shown in Fig. 6. This chip is comparable on performance
with the chip designed in this paper. The small signal
performances and large signal performances of
TGA-1171-SCC are shown in Fig. 7 and Fig. 8,
respectively. All the photos and data are from the datasheet
of TGA-1171-SCC. Compared with the chip designed in
this paper, TGA-1171-SCC has a better performance on
return losses due to the adoption of Lange coupler, but at
the expense of much larger area.
4. Conclusions
A millimeter wave high power amplifier MMIC is
designed and simulated using ADS. About 15.5 dB gain is
obtained over 33 GHz to 37 GHz. The maximum output
power can exceed 30 dBm with associated PAE of more
than 26%. This power amplifier MMIC exhibits excellent
performances in terms of power handling ability as well as
a flat gain and relatively wide bandwidth. Therefore it can
easily fit the requirements of high power applications like
radar and high speed communication.
Acknowledgment
The authors would like to thank the staff of Institute of
RF&OE-ICs, especially Mrs. Zhang Li for her help of providing
foundry documents and design PDK, and Dr. Li Qin for her
comment and suggestion on our simulation and design.
References
Table 1: Comparison of this work with some others
[1]
Works
P1dB
Gain
(dB)
Ref. [1]
36 to 45
18.0
26.0
-
2.25
Ref. [2]
Ref. [5]
CHA 5296
TGA-1171-SCC
This work
35 to 45
32 to 33
27 to 30
36 to 40
33 to 37
24.0
16.0
18.0
14.0
15.5
26.0
26.0
29.0
29.0
29.5
16
21
26
3.60
7.80
9.58
7.84
3.99
Gain and return losses (dB)
Band
(GHz)
PAE
(%)
(dBm)
Chip area
(mm2)
20
[2]
[3]
10
0
−10
[4]
−20
−30
36.0 36.5 37.0 37.5 38.0 38.5 39.0 39.5 40.0
Frequency (GHz)
Fig. 7. Small signal gain S21 (triangle symbol line), input return
loss S11 (square symbol line), and output return loss S22 (circled
symbol line) of TGA-1171-SCC.
P1dB (dBm)
34
[5]
[6]
32
[7]
30
28
[8]
26
24
36.0 36.5 37.0
37.5 38.0 38.5 39.0
Frequency (GHz)
39.5 40.0
Fig. 8. Curve of output power performance with frequency of
TGA-1171-SCC.
[9]
A. Bessemoulin, P. Quentin, H. Thomas, and D. Geiger, “A
miniaturized 0.5 watt q-band 0.25 μm GaAs pHEMT high
power amplifier MMIC,” in Proc. of the 32nd European
Microwave Conf., Milan, 2002, pp. 1–4.
A. Bessemoulin, S. Mahon, A. Dadello, G. McCulloch, and J.
Harvey, “Compact and broadband microstrip power
amplifier MMIC with 400 mW output power using 0.15 μm
GaAs pHEMTs,” in Proc. of Eurpean Gallium Arsenide and
Other Semiconductor Application Symposium, Paris, 2005,
pp. 41–44.
A. Bessemoulin, S. J. Mahon, J. T. Harvey, and D.
Richardson, “GaAs pHEMT power amplifier MMIC with
integrated ESD protection for full SMD 38 GHz radio
chipset,” in Proc. of Compound Semiconductor Integrated
Circuit Symposium, Portland, 2007, pp. 1–4.
K. Kong, D. Boone, M. King, B. Nguyen, M. Vernon, E.
Reese, and G. Brehm, “A compact 30 GHz MMIC high
power amplifier (3 W CW) in chip and packaged form,” in
Proc. of the 24th Gallium Arsenide Integrated Circuit
Symposium, Monterey, 2002, pp. 37–39.
J.-Z. Gu, J. Zhang, X.-J. Yu, R. Qian, L.-Y. Li, and X.-W.
Sun, “32 GHz MMIC power amplifier using 0.25 μm GaAs
pHEMT,” Chinese Journal of Semiconductors, vol. 27, no.
12, pp. 2160–2162, Dec. 2006 (in Chinese).
S. Cripps, RF Power Amplifier for Wireless Communication,
2nd ed. London, UK: Artech House, 2006, ch. 3, pp. 40–47.
S. Mash, Practical MMIC Design, London, UK: Artech
House, 2006, ch. 5, pp. 155–175.
W. Struble and A. Platzker, “A rigorous yet simple method
for determining stability of linear N-Port networks,” in Proc.
of the 15th Gallium Arsenide Integrated Circuit Symposium,
San Jose, 1993, pp. 251–254.
S. Goto, T. Kunii, K. Fujii, A. Inoue, Y. Sasaki, Y. Hosokawa,
R. Hattori, T. Ishikawa, and Y. Matsuda, “Stability analysis
and layout design of an internally stabilized multi-finger
84
JOURNAL OF ELECTRONIC SCIENCE AND TECHNOLOGY, VOL. 9, NO. 1, MARCH 2011
FET for high-power base station amplifiers,” in Proc. of
IEEE MTT-S International Microwave Symposium,
Philadelphia, 2003, pp. 229–232.
Bo Hong was born in Anhui Province,
China, in 1986. He received the B.S. degree
in radio engineering from Southeast
University, Nanjing, in 2008. He is
currently pursuing the M.S. degree with the
State Key Laboratory of Millimeter Waves,
Southeast University. His research interests
include GaAs based MMIC design, CMOS
RFIC design, and CMOS based millimeter
wave application.
Wen-Bin Dou was graduated from
University of Science and Technology of
China, Hefei, in 1978. He received his M.S.
and Ph.D. degrees from University of
Electronic Science and Technology of China,
Chengdu, in 1983 and 1987, respectively,
both in electronics and communications.
From 1987 to 1989, he worked with Southeast
east University as postdoctoral fellow. Since 1989, he has been
with the Department of Radio Engineering, Southeast University.
In 1994, he was promoted to professor. He is vice director of the
State Key Laboratory of Millimeter Waves. His research interests
include ferrite devices, millimeter wave quasi-optics, millimeter
wave focal imaging, antennas and scattering, millimeter wave
binary optics, and so on. He had completed many projects on
millimeter waves from State Ministries and Foundations, and
now is in charge of some key projects. He has published over
100 technique papers in journals. Two books on ferrite devices
and millimeter wave quasi-optical techniques have been
published in 1996 and 2000, respectively, and the latter has been
republished as the 2nd edition in 2006. He received many awards
from state ministry, foundation, and Southeast University. He is
the member of State Ministry Expert Committee. He is one of
editors of Progress in Electromagnetics Research (PIER, USA)
and is invited reviewer for Journals, such as “Applied Optics”,
“Journal of Optical Society of America (A)”, “Optical Express”
et al., by Optical Society
of America and magazines. He is a
nterests
senior member of Chinese
Institute
Electronics
(CIE), aas
worked
with of
Southeast
University
member of Microwavepostdoctoral
Institute of CIE,
and
a
member
of he
IEEE.
fellow. Since 1989,
has
He is the co-chairmanbeen
of program
committee
of
International
with the Department of Radio
Conference on Infrared,
Millimeter,
and University.
Terahertz In
Waves
Engineering,
Southeast
1994,
(IRMMW-THz) 2006 and
the
member
of
international
advisory
he was promoted to professor. He is vice
committee of IRMMW-THz
2009.
director
of State Key Laboratory of