Enhancing Bandwidth and Back-Off Range of Asymmetric Doherty Power Amplifier With Complex Combining Load and Post-Matching structure

A redesigned asymmetrical Doherty power amplifier (DPA) with improved efficiency, bandwidth, and output power back-off (OBO) range is presented in this paper. The proposed topology, based on the complex combining load (CCL) and asymmetric structure, allow to realize the high OBO range and broad bandwidth. In particular, the output match network (OMN) of the carrier PA of DPA is designed to increase the DPA's bandwidth by taking into account the fact that the peak amplifier's actual output impedance is not infinite at the output power backoff level. According to the logical output matching network design for carrier PA and peaking PA, the DPA can achieve broadband operation after merging to the post-matching structure. The redesigned DPA shows high-efficiency performance at 8-9 dB OBO level across the frequency band of 2.2-3.4 GHz (bandwidth of 43%). According to the simulation results, the drain efficiencies range from 47.6% to 55.5% at output back-off power levels of 8 to 9 dB and from 64.5% to 80.1% at peak power levels. This DPA has a gain of 9-12 dB over the whole operating band and a maximum output power of 42.3-45.2 dBm.