A Mode-Reconfigurable Power Amplifier with Hybrid Coupler for Enhanced VSWR Resilience

This paper presents a novel VSWR resilient power amplifier (PA) consisting of three amplifiers combined via a hybrid coupler. By switching the roles of the three amplifiers among main, auxiliary, short, and open, and by adjusting the phase difference between two independent inputs, the proposed PA reconfigures its optimal load impedance. To validate the concept, the proposed PA was implemented using GaN HEMT devices. Load pull measurements were performed to verify that the proposed PA improves efficiency by changing modes according to the load impedance. Output power and efficiency are increased by more than 1.2 dB and 1.4×, respectively, when changing modes under a VSWR greater than 4:1.