High Efficiency GaN 2.5 to 9 GHz Power Amplifiers Realized in Multilayer LCP Hybrid Technology

Abstract

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.Index Terms-Broadband amplifiers, liquid crystal, power amplifier (PA).

Pushing and Pulling [Microwave Bytes]

“…Well, I am not sure and might even say no. I have been involved in numerous exercises to design push-pull PAs at higher gigahertz frequencies and been reasonably happy with the results [5], but the hard fact is that when gallium nitride (GaN) technology came along, broader band designs could Figure 5. A neutralization scheme for push-pull triodes.…”