A 3.5/5.9-GHz dual-band output matching network for an efficiency-optimized multiband power amplifier

This paper describes the design and implementation of a dual-band output matching network (OMN) to enable the design of a dual-band power amplifier. The three-port network transforms 50-Q loads and presents, in two separate bands around 3.5 and 5.9 GHz, optimized fundamental impedances to a GaN HEMT transistor for maximum power added efficiency (PAE). The OMN is comprised of four subcircuits: two circuits perform a real-to-real impedance transformation and two perform a real-to-complex impedance transformation, connected to the transistor through a tee junction. The measured performance of the passive networks shows high isolation between the bands.