An easily implementable structure for broadband high efficiency Class-J power amplifier

This paper presents a new and easily implementable structure in the design of Class-J power amplifiers (PA) for obtaining high efficiency in wide band, based on the closed form equations for the needed impedances, on a large-signal transistor model to estimate the device's output parasitic elements and on the idea of design space. The new structure can be realized with only three sections of microstrip lines to match the fundamental and the second harmonic impedances, simultaneously. The designed amplifier using the proposed structure shows a broadband performance of greater than 60% PAE, the gain of more than 10dB and almost 40dBm output power with a 0.5-0.9GHz (57%) bandwidth. Realization of the design has confirmed the value of the idea of design space and shows the proposed structure's potential to implement the Class-J PA.