A Low Phase Noise X Band Class E Power VCO in 0.25 μm GaN/SiC Technology

This paper presents an X-band tunable voltage controlled oscillator (VCO) using WIN™ 0.25$\mu$mGaN process. The power VCO was implemented by a class E power amplifier with positive feedback to generate an output power of 27.89 dBm at 9.4 GHz. The total power consumption is 2204 mW. The DC-to-RF conversion efficiency is 27.S9%. A source-drain connected GaN transistor was used as a varactor which provided the tuning frequencies from 9.348 to 9.46 GHz. The best measured phase noise is -$121.62dBc/Hz$ at 1-MHz offset frequency. The FoM p and FoM posc are -195.49 and -223.38, respectively. The chip size includes all pads is $2\times 1.5mm^{2}$.