Transmission-line broadband GaN FET class-E power amplifier

A transmission-line loading network for class-E amplifiers is presented. In this work, a GaN FET device with a parasitic drain capacitance of 4-pF is used at 1-GHz design frequency for 20-W output power at 20-V DC supply voltage. A finite inductive reactance DC-feed class-E amplifier output network is designed based upon wire-lines and then modified using transmission-line transforms. The final network topology is managed so that it contains specific transmission-line impedances suitable for breadboarding employing air-suspended brass-bars so that no dielectric is used. The network presents the proper impedance at the device intrinsic drain and at the same time serves as broadband matching to 50-Ohms. The resultant measured performance of 80% efficiency or higher and flat output power over wide bandwidth (760-1060 MHz) is presented.