Broadband class-E power amplifier designed by lumped-element network transforms and GaN FETs

It has been shown that broadband operation of class-E amplifiers is possible using the reactance compensation technique. In this paper, broadband lumped-element network transforms are used in order to design the loading network that provides broadband reactance compensation and broadband impedance matching simultaneously while keeping high efficiency and maintaining output power within wide bandwidth. The final output network topology is canonic and alternates series and shunt components which are more suitable for practical implementation and tuning. As proof of concept, a GaN FET prototype is presented achieving 80% efficiency over 43% fractional bandwidth at around 255-MHz and 60% efficiency over an octave bandwidth at around 245-MHz.