Investigation on High-efficient Saturation Operation of Doherty-Outphasing Hybrid Power Amplifier for WPT applications

This paper performs operational analysis to improve the saturation region performance of a Doherty-outphasing Hybrid power amplifier with outphasing operation on the high output side and Doherty operation on the low output side. Three types of Doherty amplifiers, a 1:1 symmetric type and asymmetric types of 1:2 and 1:3 with 50$\Omega$ input and output using load-pull analysis, we obtained the optimum impedance at the output point with the maximum efficiency at Backoff and higher than the maximum output point of the Doherty amplifier. Furthermore, a Chireix combiner that achieves outphasing operation is designed based on the impedance. The above analysis indicates that the Hybrid power amplifier can expand the saturation point by 1.2 dB for the 1:1 symmetrical type, 1.0 dB for the 1:2 asymmetrical type, and 0.5 dB for the 1:3 asymmetrical type without changing the parameters of the Doherty amplifier with 50$\Omega$ input and output.