S-band Microwave Solid State Power Amplifier Development

It is well know that the solid-state linear Power Amplifier is one of the most important part of transmitter in the telemetry and remote control system. Its main function is to amplify the upconvertor's signal . Relative to the class Traveling Wave Tub,it has some advantages, such as, little volume, large dynamic range,low power dissipation,long natural life. At present , solid state power amplifier has wide application in the remote control subsystem of the telemetry and remote control system which made most important in research in the solid-state linear Power Amplifier . Then there is practice purpose with the research topic.There are three power transistor which have been widely used in S band now: Bipolar Junction transistor (BJT), GaAs Metal-oxide Semiconductor Field Effect Transistor (GaAs MOSFET) and Lateral Diffuse Metal-oxide Semiconductor field effect transistor (LDMOS FET) . Thanks to the advantages, such as, wide frequency , easy power supply, good stability, the LDMOS FET has used in the motion telecommunication . For the reason of the same frequency ,we use the LDMOS FET .There are three development for the Middle Power Amplifier : the first stage power amplifier, the drive stage power amplifier and the last stage power amplifier . we simulate the circuit with the Agilent ADS . After select the most suitable topology structure of circuit , we simulate the biasing circuit , input and output matching circuit . According the result of simulation , we debug the circuit .First , we analyse the power amplifier in theory in the circuit mode ,biasing point linearity ,thermal stability ,input and output matching circuit . Second , we simulate and optimize the circuit and debug the first stage ,the drive stage power amplifier . At last , we analyse deficiency of the circuit and draw a summary .