Novel GaN-Based Digital Class-E Doherty PA with High 12dB OBO Efficiency

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

Published in:

IEEE MTT-S Radio Frequency Technology and Techniques Symposium (IMS RFTT 2026), Boston, USA, Jun. 7-12, ISBN 979-8-3315-4766-0, pp. 569-572 (2026).

Abstract:

This paper presents a novel GaN-based 3-chip digital class-E Doherty power amplifier (PA) module designed to extend the back-off capabilities of the digital Doherty to deep back-off. Three identical class-E PA chips with digital input driving are combined off-chip in a two-way Doherty configuration for high efficiency in the 5G FR1 frequency band. For a single-tone input signal, the measured final-stage drain efficiency at 3.5 GHz peaks at 68% at 12 dB back-off, with a saturated output power of 33 dBm. Under a 20 MHz, 9 dB-PAPR digital OFDM input, the PA module delivers a drain efficiency of 55% at the same frequency.

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

Keywords:

amplifier, class-E, digital, digital driving, doherty, GaN, OBO, power back-off, PWM, 5G.

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