A Wideband High-Efficicncy Filtering Power Amplifier

In this paper, a high-efficiency power amplifier (PA) with bandpass filtering response is presented. It starts with the optimization goal definition for filtering PA. The fundamental and harmonic load impedance conditions are obtained from analysis and simulation to guarantee high in-band efficiency. The requirement of the out-of-band impedance is also defined with a targeted stopband rejection level. To fulfill the goals, a microstrip filtering output matching network (OMN) with several open stubs is optimized. Based on the OMN optimization, the filtering PA is implemented and fabricated. The filtering PA has good bandpass filtering feature, and the power-added efficiency (PAE) in measurement is better than 62% within 3.3-3.8 GHz.