High efficiency GaN 2.5 to 9 GHz power amplifiers realized in multilayer LCP hybrid technology

This letter presents wide bandwidth and high efficiency hybrid balanced and push-pull amplifier circuit topologies using Gallium Nitride (GaN) transistors and Liquid Crystal Polymer (LCP) multilayer circuit techniques. Push-pull circuit configurations allow differential and common mode impedances to be presented at even and odd harmonics independently, enabling the continuous mode (class BJ) design space to be exploited. Push-pull amplifiers display drain efficiencies > 40%, output power > 5 W over a bandwidth of 3.5 to 8.5 GHz at 2 dB compression levels, and under CW conditions. By comparison, although designed with identical performance goals, a conventional quadrature balanced amplifier performance is below that of the push-pull configuration