Research And Design Of Ultra-wideband Power Amplifier

Ultra-wideband power amplifier is an indispensable key instrument in various wireless transmitter systems.With the improvement of science and technology,the demand index of power amplifier for wireless communication,electromagnetic compatibility test,radar detection,electronic interference and electronic component test is getting higher.For some systems,in order to meet their anti-interference and universality,the wider the coverage bandwidth of power amplifier the better.In this paper,a 500 k Hz?1GHz power amplifier with output power greater than 20 W is designed.According to its index requirements,the power amplifier is realized by three-stage transistor cascade.The selected three-stage transistors are all unmatched transistors,and their source impedance and load impedance values are low and complex.In order to achieve ultra-wideband impedance matching,this paper usea coaxial balun impedance matching network and multistage L-shapeed impedance matching network to achieve input and output impedance matching of power amplifier.According to the driving stage transistor.In the first chapter of this paper,the application background and research value of Ultra-wideband power amplifier are introduced,and the present situation of Ultra-wideband power a,plifier at home and abroad is investigated,The second chapter introduces the classification of power amplifiers and some basic index parameters.The third one introduces one of the key technologies of power amplifier design-impedance matching circuit,focusing on the structure and working principle of coaxial balun.Chapter 4 introduces the design of ultra-wideband power amplifier,including its link design,device selection and circuit design.Finally,a new and efficient transistor heat dissipation technology is proposed.The fifth chapter introduces the debugging methods of power amplifier and the testing methods of somebasic parameters,and obtains and analyzes the test data.The working bandwidth of the ultra-wideband power amplifier designed in this paper is500 k Hz?1GHz,and the maximum output power is greater than 20 W.The gain flatness in the operating frequency range ia less than ±3d B.The input VSWR is 1.45.