A. Wentzel, C. Meliani, W. Heinrich

Published in:

European Microwave Conf. (EuMC 2011), Manchester, UK, Oct. 10-13, pp. 329-332 (2011).

Abstract:

This paper is based on a voltage-mode class-S power amplifier for the 450 MHz band using GaN-MMICs. To optimize back-off performance, the conventional topology is modified and the circuit is operated using different coding schemes for the input signal. While for the classical band-pass delta-sigma modulation, a peak output power of 2.3 W with 38% drain efficiency is obtained, tests using a pulse-width modulation approach yield significant improvements, with a maximum output power of 3 W with more than 80% drain efficiency. At 6 dB and 10 dB power back-off, 60% and 40% efficiency are achieved, respectively.

Keywords:

Microwave power amplifiers, class-S, switch-mode, delta-sigma modulation, pulse-width modulation, GaN, MMIC.

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