Design of a Bandpass Continuous Class-F Filtering Power Amplifier Based on a Terminated Coupled Lines Structure

This paper presents a filtered power amplifier (PA) based on the continuous class-F mode. This broadband filtering PA employs a terminated coupled line structure, which consists of coupled line segments and four terminations loaded on them for obtaining high efficiency over a wide frequency band. Also, a detailed theoretical analysis and calculation of the proposed termination coupling line structure is given. The filter plays the role of filtering and impedance matching simultaneously, and thus high-order harmonics of the filtering PA are suppressed. For verification, the proposed PA is designed, fabricated, and measured. The measurement results show that a drain efficiency of 60.5%–69.8%, a gain of more than 10 dB, and an output power of 40.2–42.4 dBm are achieved in the target frequency band.