Design of Bandpass Filtering Power Amplifier Based on Coupled Microstrip Line Structure

This letter presents a broadband high-efficiency power amplifier (PA) based on a series of continuous modes (SCMs). A novel filtering matching network is proposed for realizing the output matching network (OMN) of the PA. The network consists of a branch-loaded cascade-coupled microstrip line structure (BLCCMLS) and a harmonic control network (HCN). The cascaded coupled microstrip line extends the bandwidth of the filter, and this filtering OMN has high bandpass selectivity and high out-of-band rejection, which improves the efficiency of the PA. For demonstration, a 10W GaN HEMT device is used to design and implement a PA. The measurement results indicate that the designed PA achieved an output power (Pout) of 38.7-42 dBm, a drain efficiency (DE) of 60.5%-74.1%, and a gain of 8.7-12 dB at 2.05-2.7 GHz.