Co-Design of Multi-Band High-Efficiency Power Amplifier and Three-Pole High-Q Tunable Filter

This letter reports a novel methodology for co-design of broadband power amplifiers (PAs) and hightunable filters. It is for the first time demonstrated that the tunable filter’s input port can be synthesized to directly match the transistor’s output, thus eliminating the conventional broadband/band-reconfigurable matching network of the PA. This leads to minimized circuit size, volume, and loss. In this letter, a three-pole tunable bandpass filter is designed as the output matching network of a 10 W GaN PA, yielding optimal fundamental and harmonic impedances. Simulation and measured results show that the co-designed PA-filter module exhibits desired Chybeshev filter behavior while achieving efficient PA performance in the passband over a 400-MHz tuning range from 2.95–3.35 GHz. Specifically, 51%–67% efficiency, W output power, dB gain were measured throughout the entire frequency range.