A High-Efficiency, Small-Size GaN Doherty Amplifier for LTE Micro ...

38.5dBm Pout. After DPD is applied, the ACPR is better than
-50dBc.
ACPR (dBc)
-­‐20
-­‐25
-­‐30
-­‐35
-­‐40
-­‐45
-­‐50
-­‐55
-­‐60
T1G6001528 Doherty Linearity
2C 0110 10MHz LTE, 8dB PAR at 0.01%CCDF, 2650MHz
Before DPD
After DPD
33 34 35 36 37 38 39
Pout (dBm)
Eff
Fig. 9 ACPR performance with DPD
V. CONCLUSION
A 2.6 GHz GaN Doherty amplifier has been demonstrated.
At 38.5dBm average output power, in a standard LTE
frequency range of 2.62 GHz ~ 2.69 GHz, drain efficiency is
greater than 55%; gain is greater than 15dB. For a two carrier
20 MHz bandwidth 8dB PAR LTE signal, ACPR after DPD is
better than -50dBc. The Doherty amplifier dimension is 30mm
x 70mm. The combination of high efficiency and small size
made possible utilizing gallium nitride transistors in a base
station amplifier is very useful for LTE micro-cell base
stations as well as active antenna array system designs.
65
60
55
50
45
40
35
30
25
Eff ( % )
ACKNOWLEDGEMENT
The authors would like to express their appreciation for the
assistance and support of TriQuint Semiconductor’s Defense
Products and Foundry Services business unit, which provided
load pull fixtures, gallium nitride transistors and additional
resources for the initial assessment of this project, as well as
Mr. Jeff Gengler who provided DPD testing.
REFERENCES
[1] Steve C Cripps, “RF Power Amplifier for Wireless
Communication”, Norwood, MA, Artech House, 1999.
[2] Frederick H. Raab, et al., “Power Amplifier and Transmitter for
RF and Microwave”, IEEE Trans. Microwave Theory Tech.,
Vol. 50 pp. 814-826, March 2002
[3] D. Kimball, et al., “High Efficiency WCDMA Envelope
Tracking Base-Station Amplifier Implemented with GaAs
HVHBTs”, 2008 IEEE MTT-S Int. Microwave Symposium
Digest.
[4] I, Kim, et al., “Envelope Injection Consideration of High Power
Hybrid EER Transmitter for IEEE 802.16 Mobile WiMAX
Application”, 2008 IEEE MTT-S Int. Microwave Symposium
Digest .
[5] H. Deguchi, et al., “A 33W GaN HEMT Doherty Amplifier with
55% Drain Efficiency for 2.6GHz Base Stations”, 2010 IEEE
MTT-S Int. Microwave Symposium Digest.
[6] H. Sano, et al., “A 40W GaN HEMT Doherty Power Amplifier
with 48% Efficiency for WiMAX Application”, 2007 IEEE
Compound Semiconductor Integrated Circuit Symposium
Digest.
[7] N. Yoshimura, et al., “A 2.5-2.7GHz Broadband 40W GaN
HEMT Doherty amplifier with higher than 45% drain efficiency
for multi-band applications”, 2012 IEEE Topical Conference on
Power Amplifiers for Wireless and Radio Applications.
.