A broadband high efficiency Class-F power amplifier design using GaAs HEMT

Abstract

This work reveals the design for broadband GaAs Class-F power amplifier employed in terminal applications. The approximated continuous Class-F mode was analyzed and applied to GaAs device. A harmonic matching network was used to realize a broadband fundamental load impedance match while the second and third harmonic impedance are kept inside the high-efficiency region on the edge of the Smith chart. The second harmonic source impedance was also matched to improve the efficiency. The amplifier was fabricated using a 1-W GaAs HEMT device, achieved a power added efficiency above 60% from 1.3-2.1 GHz, with output power greater than 30-31.77 dBm. The maximum power added efficiency and drain efficiency are 75.26% and 81.94% respectively. The amplifier also maintained a high drain efficiency over 50% at 8-dB power back-off point. A comparison shows that this amplifier exceeds other reported GaAs Class-F power amplifiers in terms of bandwidth while high output power and efficiency are maintained.