A 14 W Wideband Supply-Modulated System with Reverse Buck Converter and Floating-Ground RF Power Amplifier

S. Paul1, N. Wolff1, C. Delepaut2, V. Valenta2, W. Heinrich1, O. Bengtsson1

Published in:

IEEE MTT-S Int. Microw. Symp. Dig., Honolulu, USA, Jun. 4-9, pp. 936-939 (2017).

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Abstract:

This paper presents a wideband supply-modulated system with a floating ground RF power amplifier and a reverse buck topology DC/DC converter. The power amplifier and the reverse buck converter are based on microwave GaN technology. The system is operating at 1620 MHz and 40 V supply and shows 39% overall power-added efficiency at an average output power of 14.6 W for an 8 MHz OFDM modulated signal with 8.6 dB PAPR. The implemented floating-ground RF power amplifier accommodates signals with up to 40 MHz bandwidth. The reverse buck converter switches at 45 MHz with a PAE of 80 - 91% over duty cycles from 40 - 100% equivalent to supply voltages of 16 - 40 V. For the first time a reverse buck topology system enabling GaN switching operation referred to ground is shown in dynamic operation with performance similar to or exceeding classical systems.

1 Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, 12489 Berlin, Germany
2 ESA/ESTEC, 2201 AZ Noordwijk, The Netherlands

Index Terms:

Envelope tracking, supply modulation, power amplifiers, space communication, DC/DC conversion.