The Development Of S Band High Gain Pulse Power Amplifier

When wireless communication technology is promoted,the receiving and transmitting systems do not transmit the digital baseband signals directly,but transmit the carrier in the microwave band which the baseband signals were modulated.Because the space environment has the attenuation effect to the microwave signal,in order to make the communication distance further,and the communication quality is better,the microwave signal will be amplified and sent into the antenna to radiate to the space.As the basic functional module of microwave signal amplification,solid state power amplifier is widely used in the field of wireless communication.In this thesis,a S band high gain pulse power amplifier is developed according to the requirements of a radar transmitter system.In order to obtain the power amplifier,three transistors are chosen to achieve the required gain and output power.The power amplifier is also used to drain modulation(two stage power amplifier)and gate modulation(final power amplifier)to achieve pulse modulated function,the signal output end of the sampling circuit to detect placed coupled power amplifier working state.The design of the control circuit makes the power amplifier have the function of over pulse width protection and over duty ratio protection,as well as the power detection port and the power indicator signal.This thesis gives the principle,technical qualification and design method of microwave solid state power amplifier.We use the software of Advanced Design System to design the three amplifiers,ensure the amplifiers of high gain,high output power in the working condition at the frequency band.We also design the coupling detector,gives the circuit of coupling detector.The box of S band high gain pulse power amplifier is simulated by using HFSS software.Ensure the resonance frequency of the box isn't the same as the working frequency,so that the power amplifier can work without be influenced by the box.The simulation model is used to draw the printed layout and the box for manufacturing.After proper debugging,a S band high gain pulse power amplifier is developed.The experimentation results show that: with the bandwidth in 400MHz(S band),the output pulse power is bigger than 44.8dBm(30W),flatness is less than 0.6dB,small signal power gain is better than 46 dB,the improvement factor is better than 80 dBc,a pulse width can limit the RF pulse width within 40 ?s.Over duty cycle function will limit the duty cycle to less than 4%.The S band high gain pulse power amplifier fully meets the requirements of the radar transmitter system.