Optimization Design of Output Combining Network Using Irregular Structure for Broadband DPA

This letter presents an optimization design method for broadband Doherty power amplifier (DPA) using an irregular output combining network (OCN). First, the postmatching network and the output matching networks are considered as the overall OCN, and the three-port S-parameters of the OCN are analyzed and calculated using the impedances at power back-off (PBO) and saturation. Subsequently, to improve the feasibility of optimization, several impedances that meet the requirements are used to calculate feasible S-parameter solution sets, which can be used as the optimization target. Finally, an optimization method of the OCN using an irregular structure is proposed. For verification, a 1.2–2.8-GHz broadband DPA is designed and measured. The results show that with the saturated output power exceeding 43.1 dBm, drain efficiencies of 54.1%–74.2% and 50.9%–56.5% are obtained at saturation and 6-dB PBO, respectively.