Design of an Outphasing Power Amplifier Using Complex Combining Method for Broadband Application

This letter presents the design of a broadband outphasing power amplifier (OPA) based on complex combining impedance. The complex combining impedance is realized using a post-matching network (PMN) and is utilized to compensate for the frequency dispersion of the active load modulation in the OPA. It is illustrated for the first time that the bandwidth of an OPA can be extended by elaborately designing the complex combining impedance. To validate the proposed method, a broadband OPA operating over 1.7–2.2 GHz is designed and implemented. Measurement results show the fabricated OPA achieves a saturation power of 43.1–44.3 dBm, a saturation drain efficiency (DE) of 63.4%–78.4%, and a 6-dB back-off DE of 45.5%–70.4% in the interested frequency band.