Codesign of a Broadband Doherty Power Amplifier with Microstrip Bandpass Filters

A broadband Doherty power amplifier codesigned with filters and a series of continuous modes is presented. Three bandpass filters are used to design post matching network, output matching network for carrier and peaking stages. These filters can not only suppress the harmonics but also interferences outside the operating band of the power amplifier. Theory named a series of continuous modes is used to transform impedance looking from carrier stage into power combing point to the objective high efficiency design space while even-odd-mode analysis is used to analysis the response of the three BPFs. Finally, a broadband 6-dB output back-off DPA operating in 1.3-2.2 GHz is designed. Simulation results exhibit output backoff drain efficiency of 56.0%-78.6% and saturated drain efficiency of 42.1%-60.2%. Moreover, the saturated output power level is 43.3-44.9 dBm with a gain of 10.3-11.8 dB.