High-Efficiency Power Amplifier Using an Active Second-Harmonic Injection Technique Under Optimized Third-Harmonic Termination

Author

Mincheol Seo ; Hwiseob Lee ; Jehyeon Gu ; Hyungchul Kim ; Ham, Jaap ; Wooyeol Choi ; Yanghun Yun ; Kenneth, K.O. ; Youngoo Yang

Author_Institution

Microwave Circuits & Syst. Lab., Sungkyunkwan Univ., Suwon, South Korea

Volume

61

Issue

8

fYear

2014

fDate

Aug. 2014

Firstpage

549

Lastpage

553

Abstract

This brief presents an active second-harmonic injection technique to improve the efficiency and bandwidth for high-efficiency power amplifiers (PAs). An optimum third-harmonic termination condition was examined for higher efficiency after the second-harmonic injection using a multiharmonic load-pull simulation. It was determined that the optimum third-harmonic termination is the same as that of the inverse class-F PA. Based on this result, a high-efficiency PA with an optimized third-harmonic termination for the second-harmonic injection was designed for a center frequency of 1 GHz as a main amplifier. The overall system requires an auxiliary second-harmonic amplifier and a diplexer between the main and auxiliary PAs. The PA with an optimized third-harmonic termination for the second-harmonic injection was implemented using a 10-W GaN high-electron-mobility transistor for both the main and auxiliary power stages. Compared with the PA without second-harmonic injection, the bandwidth with a power-added efficiency of more than 80% is extended from 60 (960-1020 MHz) to 180 MHz (880-1060 MHz) after the second-harmonic injection.

Keywords

III-V semiconductors; UHF power amplifiers; gallium compounds; high electron mobility transistors; multiplexing equipment; wide band gap semiconductors; GaN; HEMT; active second-harmonic injection technique; auxiliary power stages; auxiliary second-harmonic amplifier; diplexer; frequency 880 MHz to 1060 MHz; frequency 960 MHz to 1020 MHz; high-efficiency power amplifier; high-electron-mobility transistor; inverse class-F PA; main power stages; multiharmonic load-pull simulation; optimum third-harmonic termination; power 10 W; third-harmonic termination optimization; Bandwidth; Circuits and systems; Gallium nitride; Harmonic analysis; Impedance; Power generation; Power system harmonics; High-efficiency power amplifier (PA); inverse class-F PA; second-harmonic injection;

fLanguage

English

Journal_Title

Circuits and Systems II: Express Briefs, IEEE Transactions on

Publisher

ieee

ISSN

1549-7747

Type

jour

DOI

10.1109/TCSII.2014.2327382

Filename

6823125