Design of a High-Power, High-Efficiency GaN Power Amplifier for W-Band Applications

This paper presents a W-band high-efficiency and high-output-power power amplifier (PA) based on a 130 nm AlGaN/GaN-on-SiC HEMT process. The PA is designed to deliver optimal output power and gain performance across the entire W-band. A balanced architecture is adopted, combining two amplifier units through Lange couplers. High- and low-impedance microstrip lines are employed for input, output, and inter-stage matching. Each amplifier core adopts a three-stage configuration with gate width ratios of 1:2:4 to enhance gain. The bias network incorporates MIM capacitors and thin-film resistors to improve stability. Measured results indicate a small signal gain exceeding 17 dB under a gate voltage of -2.2 V and a drain voltage of +20 V. Within the 80-86 GHz frequency range, the PA achieves an output power above 34 dBm with a 22 dBm input power, corresponding to a power gain above 12 dB and a power-added efficiency (PAE) greater than 20%. The chip occupies a compact area of 2.65 mm × 3.75 mm. Compared with previously reported works, the proposed PA demonstrates the highest PAE within the 80-86 GHz band.