A novel design methodology for extended continuous class-F power amplifiers in wireless applications

In this paper, an extended continuous class-F power amplifier (PA) is investigated, designed, and fabricated. The new auxiliary parameter (β +αcos^2θ) , is proposed to increase the efficiency in comparison with the old auxiliary parameter (1+δcosθ) . A novel methodology based on the smith chart design space and the proposed auxiliary parameter is introduced and analyzed. The design methodology, by controlling harmonic interferences, expands the amplifier bandwidth to below 1 GHz (up to 200 MHz). The laterally diffused metal–oxide–semiconductor (LDMOS) is selected, and an optimal bias point for its best performance is considered. Also, microstrip feedback based on the low-impedance coupled line is designed to accomplish transistor unconditional stability. Then, a ladder network based on the radial lines is designed as a harmonic control circuit, which controls harmonics up to 5th into the proposed design space. To verify this design approach, an extended continuous class-F power amplifier is designed and fabricated to operate at 0.2–1.7 GHz frequency range. Measurement results of the implemented PA shown that the output power of 38–40.2 dBm and the power gain of 13–15.2 dB were obtained. In addition, the final PA achieved a remarkable 53–79