GaN-Based Digital Class-E Doherty Power Amplifier for 5G FR1 Frequency Band

G. Bartolotti^#, A. Piacibello^#, V. Camarchia^#, D. Sun^$, T. Hoffmann^$, A. Wentzel^$

Published in:

Proc. 55th European Microwave Conference (EuMC 2025), Utrecht, Netherlands, Sep. 23-25, ISBN: 978-2-87487-081-1, pp. 1087-1090 (2025).

Abstract:

This paper presents for the first time a GaN-based digital class-E Doherty power amplifier module (PA) for the 5G FR1 frequency band. Two identical class-E PA MMICs with digital pulse-width modulated (PWM) input driving are combined in a two-way Doherty configuration for high efficiency over an extended output back-off (OBO) range up to 9 dB. A wideband Doherty combiner design strategy is adapted to the class-E capabilities of the PAs to achieve high-efficiency for low power levels leading to an extended back-off range. At 7.5 dB OBO, the measured final-stage drain efficiency (η_drain) peaks at 68% for 3.4 GHz PWM single-tone input signal. Over a 3.2-3.6 GHz frequency range the prototype achieves a minimum of 52% η_drain at 9 dB OBO. The maximum saturated output power is 32.8 dBm. At 3.3 GHz, the PA module achieves 60% and 59% η_drain for a 20 MHz and 100 MHz 9 dB PAPR digital OFDM input signal, respectively.

^# Politecnico di Torino, Italy
^$ Ferdinand-Braun-Institut (FBH), Germany

Keywords:

Back-off, Class-E, Digital, Doherty, GaN, PWM.

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