Wideband Quasi-Balanced Doherty Power Amplifier with Reciprocal Main/Auxiliary Setting and Mismatch-Resilient Parallel/Series Reconfiguration

Abstract

This paper presents a novel reconfigurable quasi-balanced Doherty power amplifier (QB-DPA) with wide bandwidth and strong resilience to load mismatch. By leveraging the complementarity of reciprocal main/auxiliary setting and parallel/series modes, we demonstrate the first-ever broadband mismatch-resilient QB-DPA. To validate the proposed theory, a broadband 1.55-2.7-GHz QB-DPA is developed using GaN technology and 3-section branch-line coupler. With matched load, the experimental results exhibit an efficiency of 57-80% at peak output power and 49–71 % at 6-dB output back-off (OBO), respectively. Modulated measurement using a 20-MHz LTE signal with 10.5-dB peak to average ratio (PAPR) shows a 44–51 % average efficiency across the operation bandwidth and up to −36 dB ACPR. More importantly, a consistent output power and improved efficiency at OP 1dB are experimentally maintained through the parallel/series modes reconfiguration at 2: 1 voltage standing wave ratio (VSWR).