A 56 W Power Amplifier with 2-Level Supply and Load Modulation

S. Kelz1, M. Schmidt2, N. Wolff1, M. Berroth2, W. Heinrich1, O. Bengtsson1

Published in:

10th German Microwave Conference (GeMiC 2016), Bochum, Germany, Mar. 14-16, ISBN 978-3-9812668-7-0, pp. 185-188 (2016).

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Abstract:

Dynamic load modulation is proposed to improve the efficiency of an RF power amplifier with discrete supply modulation. A 47.5 dBm, 2.7 GHz power amplifier is realized to show the potential of the method. The amplifier design is based on continuous wave load-pull measurements to determine the optimum load impedances, using the statistics of a 10.2 dB PAPR OFDM signal. The output network contains a single SiC varactor for adaptive output matching. The supply voltage is adjusted by a 2-level supply modulator. Static evaluation of the amplifier shows an improvement in PAE of approximately 9.7 percentage points at 10 dB back-off due to load modulation.

1 Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Str. 4, 12489 Berlin, Germany
2 Institut für Nachrichtentechnik, Universität Stuttgart, Pfaffenwaldring 47, 70550 Stuttgart, Germany

Keywords:

dynamic load modulation; voltage supply modulation; power amplifiers; varactors.