1.6 GHz – 3 GHz, 10W, 60% efficiency class-J PA for cognitive radio applications

This paper presents the design of a broadband, 1.6-3 GHz, 10 W class-J power amplifier (PA). Analytical expressions of theoretical current and voltage waveforms as well as the fundamental and second harmonic impedance derivations are provided. Taking into account the extrinsic parasitic elements and the nonlinear drain-source capacitance of the packaged RF power transistor, an external output matching network is designed to provide the proper impedances on the design space to the transistor current source plane. Source-pulling of the transistor led to the design a broadband input matching network. The designed amplifier exhibits greater than 60% efficiency and almost 40 dBm output power over 1.4 GHz frequency bandwidth.