T. Hoffmann, L. Schellhase, W. Heinrich, A. Wentzel

Published in:

IEEE MTT-S Int. Microw. Symp. Dig., Denver, USA, Jun. 19-24, ISBN 978-1-6654-9613-1, pp. 622-625 (2022).

Abstract:

This paper presents for the first time a GaN-based digital class-E outphasing power amplifier (PA) for 5G applications in the 4 GHz range. The amplifier consists of two digital PA MMICs with a 4:1 size ratio between the final-stage transistor gate-widths. A bond-wire-based load network shapes the typical class-E waveform characteristics and combines the two outputs for outphasing at 4 GHz in order to maximize efficiency, also at power back-off (PBO). Moreover, due to the digital design of the PA MMICs the frequency of operation can be easily changed by adjusting the output network, which is a major advantage compared to reactively matched class-E chips.
At 4 GHz a maximum output power (P_out) of 8.4 W and a power gain of 23 dB has been reached for a final-stage drain supply voltage (V_dd) of 27 V. Peak final-stage drain efficiencies (η_drain) of 84% and 38% were achieved for a V_dd of 10 V at 0 dB and 11.2 dB PBO, respectively. Due to its flexibility regarding digital input and operation modes (PWM, outphasing, switch off one PA) the proposed PA module is a promising candidate to reduce energy consumption in 5G base stations.

Keywords:

digital, PWM, switch-mode, power amplifiers, GaN, class-E, outphasing, MMIC.

Copyright © 2022 by IEEE. All rights reserved.
Copyright and Reprint Permission: Abstracting is permitted with credit to the source. Libraries are permitted to photocopy beyond the limit of U.S. copyright law for private use of patrons those articles in this volume that carry a code at the bottom of the first page, provided the per-copy fee indicated in the code is paid through Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923. For reprint or republication permission, email to IEEE Copyrights Manager at pubs-permissions@ieee.org.

Full version in pdf-format.