Design of a High-Efficiency 4 W GaN HEMT Power Amplifier MMIC for Ka-Band SATCOM

This paper presents the design of a high-efficiency Ka-band 5-W-class monolithic microwave integrated circuit (MMIC) power amplifier using a 120 nm GaN high-electron-mobility transistor (HEMT) process. To achieve a high efficiency, the transistors for the driver and main stages were matched to their optimal impedances. A three-stage configuration was adopted to ensure a signal gain of at least 25 dB. The proposed power amplifier MMIC operates in the frequency range of 29~31 GHz and has a die area of as small as 1,660×2,830 μm2. Measurements using a continuous-wave (CW) signal showed that the designed power amplifier MMIC exhibited an output power of over 36.0 dBm and a power-added-efficiency (PAE) of 29.2 % for the 29~31 GHz band.