Linearity Analysis of a 40 W Class-G-Modulated Microwave Power Amplifier

N. Wolff1, O. Bengtsson1, M. Schmidt2, M. Berroth2, W. Heinrich1

Published in:

Proc. 45th European Microwave Conf. (EuMC 2015), Paris, France, Sep. 7-10, pp. 1216-1219 (2015).

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Abstract:

In this paper, a class-G power amplifier is presented. It consists of a discrete class-G supply modulator, which uses a GaN-HEMT for switching, connected to a 2.65 GHz power amplifier with 40 W peak power, specifically designed for class-G supply modulation. The focus of the paper is on evaluating this system in terms of the RF and the switching signal, the switching behavior, and linearity. A combination of a complex memory polynomial digital predistorter and lookup tables as well as class-G-optimized digital predistorter models is used to improve the linearity of the power amplifier. It is found that the Class-G modulation improves overall PAE by 10-15 %. It is shown that using dedicated digital predistortion the linearity the distortions caused by the modulator can be significantly reduced.

1 Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Straße 4, 12489 Berlin, Germany
2 Institut für Elektrische und Optische Nachrichtentechnik, Universität Stuttgart, Stuttgart, Germany

Keywords:

RF power amplifier; supply modulation; class-G modulation; digital predistortion; linearity.