A myriad of products and services utilize RF power amplifiers in their transmitter circuitry: wireless infrastructure for cell phones and other mobile devices; radio and television broadcasting; medical equipment such as MRI machines; materials curing that includes carpet fibers and plywood; radar; space and satellite communications; police and fire radios; and military communications and electronics of all kinds. Most of these transmitters use semiconductors in the RF power amplifier output stages. Even modern, extremely high-power broadcast transmitters that traditionally have used large vacuum tubes in their RF sections have finally begun to use solid-state devices.
This study examines RF power semiconductor devices that have power outputs of greater than three watts and operate at frequencies of up to 4 GHz, which represent the bulk of applications in use today. Both silicon based and gallium based devices are covered.