CW 20-W AlGaN/GaN FET Power Amplifier for Quasi-Millimeter Wave Applications

This paper describes an AlGaN/GaN FET power amplifier module delivering a continuous wave (CW) output power of more than 20 W at 26 GHz. To achieve high breakdown characteristics with reduced current collapse and high gain, we have developed a 0.2 µm-long recessed-gate AlGaN/GaN FET with a field-modulating plate (FP), achieving high operation voltage of 25 V even at quasi-millimeter wave frequencies. A single-ended AlGaN/GaN FP-FET amplifier module for quasi- millimeter wave frequency has been fabricated for the first time. The amplifier module developed using a 6.3-mm-wide single chip recessed-gate AlGaN/GaN FP-FET exhibited an output power of 20.7 W, a linear gain of 5.4 dB and a power-aided efficiency of 21.3% at 26 GHz. This is the highest output power in solid state power amplifiers at over 20 GHz.