A GaN-on-Si MMIC Power Amplifier with 10W Output Power and 35% Efficiency for Ka-Band Satellite Downlink

The design and experimental characterization of a Monolithic Microwave Integrated Circuits (MMICs) Power Amplifiers (PAs) specifically conceived for next generation Ka-band Very High Throughput Satellites (vHTS) are discussed. The chip has been implemented on a commercially available 100nm gate length Gallium Nitride on Silicon (GaN-Si) process. The design was carried out accounting for the peculiarities of the application, therefore the selection of the devices' bias points and the matching network topologies was driven, and then accomplished, by carefully considering the thermal constraints of the technology, in order to keep the junction temperature of all devices below 160 degrees C. The MMIC, based on a three stage architecture, has been fully characterized from 17.3GHz to 20.2 GHz. In such a frequency range, it delivers an output power larger than 40dBm with a power added efficiency peak higher than 40% and 22 dB of gain.