A Harmonic Termination Technique for Single- and Multi-Band High-Efficiency Class-F MMIC Power Amplifiers

This paper presents a harmonic termination technique for single- and multi-band high-efficiency class-F monolithic microwave integrated circuit (MMIC) power amplifiers (PAs). The harmonic termination network (HTN), realized with the minimum possible number of elements, can be used to terminate an arbitrary number of harmonics in a single-band PA or harmonics of multiple frequencies in a concurrent multi-band PA. The drain and gate bias lines are embedded in the HTNs to obviate the need for RF chokes and reduce the chip area. A single- and a dual-band MMIC PA are designed using the proposed technique and implemented in a 0.25- μm AlGaAs-InGaAs pHEMT technology. The single-band 5.5-GHz PA provides 27.5 dBm of output power with 70% power-added efficiency (PAE). This PAE level is achieved by terminating the first five harmonics at the output as well as the first three harmonics at the input of PA. The dual-band PA, operating at 5 and 12 GHz, delivers the output power of 28.0 and 26.7 dBm with PAE of 58% and 51%, at the two frequency bands, respectively.