A High Efficiency Three‐Way Power Combiner Used in SSPA

ABSTRACT A high efficiency three‐way power combiner used in solid state power amplifier (SSPA) is proposed in this letter. The power combiner is a six ports circuit composing of cover plate, PCB and base plate, which can achieve three‐way signals power combining with broadband and high isolation. Compared with the existing three‐way power combiner, branch microstrip lines are adopted instead of isolation resistors between branch lines, and this structure can avoid resistance loss and improve power combining efficiency. From the measured results, less than 4.8 ± 0.2 dB of the three equivalent insertion losses, more than 21 dB of the return loss, and better than 19 dB of isolation from 6.5 to 8 GHz can be achieved. Further processing and testing of back‐to‐back samples were carried out, and the power combining efficiency of the combiner reached over 94.4%. Based on the combiner, a 200 W solid‐state power amplifier was developed with a DC efficiency of 37.5%.