High-Efficiency Class-E/F3 Power Amplifier

Abstract

The wireless communication technique has developed fast in modern society, whose applications need higher power for carrier signals to transmit long distances. Some techniques operate at 13.56MHz, like Radio Frequency Identification and Near Field Communication. For wireless communication, it is important to transfer DC power to AC power, which is done by power amplifier. Enhancing the efficiency of the power amplifier is necessary due to its ability to save energy. This project analysed three different solutions to enhance the efficiency of power amplifier operating at 13.56MHz and made comparison of them. Firstly, a power amplifier with output impedance matching network based on transformer was conducted. Secondly, an impedance matching network with harmonic suppression function was designed and measured, whose power-added-efficiency (PAE) was higher than the first circuit. Finally, to further enhance PAE, an impedance matching network based on Class-E/F3 topology was designed and measured, which lead to an obvious higher PAE than the previous two topologies. Class-E/F3 mode is a hybrid of Class-E and Class-F3-1 mode, which has the advantages of both the simplicity of Class-E and good performance of Class-F-1. [9] The study concludes varies types of matching network to increase the PAE of the power amplifier at 13.56 MHz and analyses these different circuits and exhibits that the Class-E/F3 topology can increase PAE most.