Design of a Dual-Input Doherty Power Amplifier With Selectable Output Port

Power amplifiers (PAs) equipped with selectable or switchable output ports can often improve the performances of the microwave systems, especially in radar and satellite communication systems where both horizontal and vertical polarization can be utilized. To enable a selectable output port, this brief develops a dual-input dual-output (DIDO) Doherty power amplifier (DPA), which has a simple circuit topology. The DIDO-DPA is consists of two identical sub-amplifiers and a 90° coupler. The input amplitudes of the two sub-amplifiers and their phase difference is dynamically controlled leveraging on the dual-input technique, leading to a flexible power transferring and enhanced back-off efficiency. As a validation, a DIDO-DPA operating at 2.4 GHz is fabricated and measured in this brief. The fabricated DIDO-DPA delivers an output power of more than 43.3 dBm, a maximum drain efficiency (DE) of more than 69.5%, and a 6-dB back-off DE of more than 58% at each output port.