Very High-Power RF Transistors and Transistor Amplifiers

This article describes the recent advances in very high-power transistors and amplifiers for applications above 1MHz. It focuses primarily on GaN-on-SiC HEMT devices for pulsed applications. The advantages of using drain supply voltages at 100V and above are shown, and discusses the factors limiting the maximum RF power output. Finally, it discusses methods of combining these very high-power transistors and shows an example of a two-transistor RF amplifier pallet measuring just 4.6” x 1.7” that delivers a minimum of 3.5 kW over 2.7 – 2.9 GHz with 60% efficiency.