A Ka-Band Doherty Power Amplifier in a 150 nm GaN-on-SiC Technology for 5G Applications

This paper presents a Ka-band three-stage power amplifier for 5G communications, which has been implemented in a 150 nm GaN-on-SiC technology and adopts a Doherty architecture. The amplifier is made up of a 50 Ω input buffer, which drives a power splitter, thanks to which it delivers its output power to the two power amplifier units of the Doherty topology, namely the main and auxiliary amplifier. Finally, the outputs of the two power amplifiers are properly arranged in a current combining scheme that enables the typical load modulation of the Doherty architecture, alongside allowing power combining at the final output. The proposed amplifier achieves a small signal gain of around 30 dB at 27 GHz, while providing a saturated output power of 32 dBm, with a power-added efficiency (PAE) as high as 26% and 18% at peak and 6 dB output power back-off, respectively.