GaN digital microwave outphasing PA

T. Hoffmann, A. Wentzel, T. Flisgen, F. Hühn and W. Heinrich

Published in:

Int. J. Microwave Wireless Technolog., vol. 12. no. 7, Special Issue: EuMW 2019 Special Issue, pp. 567-577, doi:10.1017/S1759078720000367 (2020).

Copyright © Cambridge University Press and the European Microwave Association 2020. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the Cambridge University Press and the European Microwave Association.


This paper presents a novel GaN-based digital outphasing power amplifier (PA) for the 800 MHz range. The PA reaches a maximum output power of 5.8 W at 30 V final-stage (FS) drain supply voltage. A novel output combiner circuit is used and efficiency is improved by resonant commutation of the FSs and optimized driver circuits for the two GaN push-pull FSs. 3D electromagnetic simulation of output network has been conducted to extract an equivalent circuit model and to access full information in terms of functionality and broadband impedance characteristics for optimized outphasing operation in the final design. Measured total efficiencies (ηtot) of 59 and 25% at 0 and 10 dB power back-off are achieved, respectively, fitting the simulation quite well. The proposed digital outphasing module is a promising candidate for fully digitized base-station architectures in future wireless communications.

Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Berlin, Germany


Digital, power amplifier, outphasing, resonant commutation, class-D, class-S, GaN