An S-band 3-W load-reconfigurable power amplifier with 50–76% efficiency for VSWR up to 4:1

Abstract

A load-configurable high-efficiency power amplifier (PA), co-designed with a two-pole evanescent-mode (EVA) cavity-base impedance tuner, is demonstrated in this paper. A high-Q impedance tuner is used as the output matching network of the power amplifier to properly terminate the transistor various load impedances. The presented design is experimentally validated using GaN transistor and measured at 2.5 GHz. The quality factor of the impedance tuner is extracted from measurements and found to be approximately 300. The PA with the impedance tuner reaches 76% efficiency at VSWR = 1, 63–75% at VSWR = 2, and 50–62% at VSWR = 4. The maximum output power of the PA is 35 dBm (3.16 W).