High Efficiency Class-E RF Power Amplifier For Acoustic-optic Q-switch Driver

This thesis does research on the key module of Q-switch driver—high efficiency Class-E power amplifier, including the design and implement of the prototype.First,the characteristics of the conventional power amplifiers and the typical ways to improve the efficiency are presented .The Q-switch principle and technical requirements of Q-switch driver are also analysed and the Class-E mode is selected. Then the basic principles of the Class-E amplifier are explained, the ideal parameters for the design are calculated, the causes that result in losses are listed, and the Pspice circuit simulations are presented.This thesis is mainly on the actual design and debugging process of power amplifier. Considering the voltage and the power output, two grades form of cascades Class-E power amplifiers are designed, and the realization of the output matching network is also the necessary part.The total capacity of gain reaches 25dB.This thesis also described the collector modulation of the Class-E amplifier and the circuit for protection.During the debugging process, the overheating problem of power transistor in output level became the difficulty of the project. This thesis analyzes its reasons. Through the actual tests, some effective treatments are given finally, and the tests of small batch in prototypes have been done.The results show that these are the effective solutions.Experimental prototypes and small batch prototypes are tested for standing wave ratio, output power, efficiency and so on, the amplifier meets technical requirements, and the measured PAE is up to 57.3%. After three consecutive 72-hours reliability tests, all technical performances are stability. End-users in industrial settings trialed for four months without faults, so the design is acclaimed by the users.Finally, the results of the research are concluded and further improvements are attached.