Design of a Dual-Band Outphasing Power Amplifier Based on Multiple Topology Fitting

This brief presents the design of a dual-band outphasing power amplifier (OPA) using multiple topology fitting. By adding extra transmission lines to the traditional noncommensurate transmission lines, the design space for the output combiner is largely expanded. Different line combinations with good load modulation effects can be chosen according to frequency and circuit dimension. As a proof of concept, a prototype OPA operating at 2.6 and 3.5 GHz is fabricated based on two 10-W GaN HEMTs. The fabricated circuit achieves saturation output power of 44.4 and 44.3 dBm at the two selected frequency bands, with accompanying peak drain efficiencies of 69.5% and 69.2%. Meanwhile, the corresponding efficiencies at 6-dB power back-off points are 62.4% and 63.5%, respectively.