A hybrid two stage 20-W GaN HEMT Ku-band power amplifier for very small aperture terminals

Abstract

This contribution is about a two stage power amplifier (PA) in hybrid microwave integrated circuit (MIC) technology covering the extended Ku-band uplink (13.75–14.5 GHz) for satellite communication. A high relative permittivity alumina substrate and a 250 nm GaN bare-die technology have been chosen to realize the matching circuits of the amplifier. A systematic design approach using simulation-based multi-frequency source- and load-pull analyses in order to find optimum load and source impedances for maximum output power was applied for the proposed PA. The measured output power is about 14 W for a continuous wave (CW) signal with a PAE of more than 22% in the frequency range of interest. Additionally, modulated measurements including a modern pre-distortion technique state an average output power of 12 W and a peak power of about 22 W achieving a PAE of 20% using a 8PSK signal.