High power-density monolithic linear X-band power amplifier using a low-cost MESFET technology

A physically small high-efficiency linear class-A monolithically integrated power amplifier is presented in this work. The power amplifier was fabricated on a general-purpose high-volume 0.6 μm GaAs MESFET process. The small chip size of 0.32 mm² could be obtained through the use of microstrip transmission lines instead of lumped components. The circuit delivers a maximum linear output power of 24.2 dBm. The monolithic microwave integrated circuit (MMIC) exhibits a power density per chip area of 0.82 W/mm² at 12.2 GHz. At present, this value is amongst the highest reported in the open literature. A high power added efficiency for class-A operation of 33.9 % as well as a maximum small-signal gain of 8.3 dB was achieved. Using a general-purpose process, instead of a dedicated power process, allows the integration of the power amplifier with other RF front-end blocks in next-generation X-band communication systems targeting mass-production.