Design of a highly PAE class-F power amplifier using front coupled tapered compact microstrip resonant cell

This article presents the design and implementation of a class-F power amplifier (PA) with a low voltage pHEMT, using a novel Front Coupled Tapered Compact Microstrip Resonant Cell (FCTCMRC) for obtaining a high-efficiency performance. The FCTCMRC is used as a harmonic control circuit, which is short and open circuit for the second and third harmonics, respectively. The required dc-supply voltage is low due to application of a low-voltage pHEMT in the circuit implementation. Therefore, the class-F power amplifier is designed with a high power added efficiency (PAE) and compact circuit size. To verify the method, the designed class-F PA is fabricated using a pHEMT at 1.1 GHz. The proposed class-F power amplifier using the FCTCMRC has obtained 86%PAE under 10 dBm input power, which achieves 16% improvement, also, the circuit size including the harmonic control circuit and output matching is decreased about 25%, all in comparison with the designed PA using the conventional CMRC. The measurement results of the fabricated power amplifier are in good agreement with the simulation results, which verifies the proposed design methodology.