Bandwidth enhancement of three-device Doherty power amplifier based on symmetric devices

IEICE Electronics Express

Shichang Chen¹  Guohua Liu¹  Zhiqun Cheng¹  Steven Gao¹  Ming Zhang² 

[1] Key Lab. of RF Circuit and System, Education Ministry, Hangzhou Dianzi University;Key Laboratory of Nanodevices and Applications, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences

关键词: Doherty power amplifier;    broadband;    drain efficiency;    three-device;    symmetric devices;   

DOI  :  10.1587/elex.15.20171222

学科分类：电子、光学、磁材料

来源: Denshi Jouhou Tsuushin Gakkai

【 摘 要 】

This paper proposes a method for extending the bandwidth of a three-device Doherty power amplifier (DPA) based on symmetric devices. λ/4 transmission lines are inserted between each peaking amplifier output and carrier amplifier output to compensate load impedance of carrier amplifier. In order to achieve perfect load modulation, carrier amplifier output circuit total electrical length is designed to 90 degrees, and the peak amplifier output total electrical length is designed to 180 degrees. The proposed method is demonstrated by designing a three-device broadband DPA using three 10-W packaged GaN HEMT devices. Measurement results show that over 40% drain efficiency is achieved at 9-dB back-off power, over the frequency band of 1.45–2.35 GHz, accounting for 46% fractional bandwidth.

【 授权许可】

CC BY