100W and 80% Efficiency GaN PA for VHF Space-Borne Earth Sensing Applications

In this paper, the design of a hybrid power amplifier (PA) in the very high frequency (VHF) band for satellite remote sensing applications is discussed. A Class <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{F}^{-\mathbf{1}}$</tex> design strategy was adopted to maximize the efficiency performance of the space-evaluated CHKA012bSYA GaN packaged device from United Monolithic Semiconductors. The proper shaping of voltage and current waveforms across the device terminals was achieved by careful design of the output matching network using resonating L-C filters. A 75% de-rating was applied in the design process to ensure compliance with space reliability requirements. The proposed PA provides an output power exceeding 100 W with a power added efficiency and a gain of about 80% and 25 dB, respectively, within 40−50 MHz.