Development Of L Band Pulsed Power Amplifier

RF power amplifier is one of the important equipments in modern communicationsystem,is widely used in radar,satellite navigation,mobile phonecommunications,radio and television,instrumentation system etc. With thedevelopment of application and communication equipment new technology for highspeed wireless digital communication, multi carrier modulation technology as wellas the miniaturization requirement, also put forward higher requirements on the RFpower amplifier, high power, small size,high efficiency, high linearity andhigh reliability has become the development trend of power amplifier.This paper based on the design of RF power amplifier are described, analyzed thebasic theory of amplifier design and main index, introduces the classification ofamplifier. Then according to the requirements of the project technical indicatorsformulated the plan as a whole. The RF circuit simulation software ADS is used forthe final power amplifier DC simulation, stability analysis, the bias circuit simulationand matching circuit simulation design. And through the pulse control circuit reducesthe overall power dissipation of module; select the appropriate storage capacitor tomake the pulse rise/fall time meet the demand of the system; design temperaturecompensation circuit to make the gain variation is not too much under theenvironment of all temperature range.real-time monitoring circuit design of poweramplifier temperature, power, in the abnormal state through the external controlprocessor shut off the power amplifier. Then design the module internal layoutaccording to requirements of the structure, finally complete the power amplifierthrough the assembly debugging. Designed a L-band pulsed power amplifier usingLDMOS.The power amplifier working at960MHz to1225MHz, the output power is notless than80W at-55℃-+70℃, pulse rise/fall time is less than100ns, and pulsewaveform drop is less than5%.