Implementation And Stability Of High Efficiency Class-E Power Amplifier

For decades,RFID technology has made rapid progress.Amplifier systems play an important role in amplifying small signals and transmitting them to space through transmission antennas at the desired operating frequencies.Among the total power dissipated by the transmission system,the power amplifier accounts for the largest proportion.At the same time,in the process of signal transmission,the impedance mismatch is caused by the changes of the external environment,and the amplifier is easy to introduce harmonic components and cause self-exciting oscillation.This instability factor has great harm to the equipment.Therefore,the research on high efficiency and stability of power amplifier system has become a hot issue in the field of RF microwave.In this thesis,the design of traditional Class-E amplifier is studied in depth,and then on the basis of extensive literature reading,a set of high efficiency,high stability amplifier system is designed.Firstly,the structure of power amplifier circuit and filter is selected and designed to overcome the shortcomings of rich harmonics and poor stability caused by the use of power amplifier tube as a switch.Next,the effect of using annulus,diplexer and directional coupler on the stability of the power amplifier system is studied.Finally,based on the above conclusions,a class E power amplifier with output power of 10w and working at the main frequency of 13.56MHz is designed.After PCB debugging and summarizing and analyzing the test results,it is shown that the output power,efficiency and spectrum results basically meet the design requirements,and its stability is verified.From the results,it can be seen that when the impedance of the load antenna varies within a certain range,the output of the power amplifier system can still maintain a stable level to achieve the design purpose.The amplifier system designed in this thesis is improved on the basis of the traditional Class-E amplifier design.It plays a key role in improving the high-order harmonic interference of the system,reducing the sudden change of working mode caused by external changes,and is conducive to improving the stability of the amplifier transmission system and the reliability of data transmission.