| Microwave wireless transmission has a lot of advantages,such as long distance,small loss and good directivity,which other wireless transmission modes can not compare with.It can carry on high power energy transmission in a long distance and has a broad application prospect in the fields of space solar power generation,smart home,medical equipment in the body and so on.RF power amplifier is an important part of microwave wireless transmission system,which directly affects the performance of microwave wireless transmission system.Most of the power amplifiers used in the wireless transmission research at home and abroad are designed for wireless communication.In order to ensure the linearity,these products make certain sacrifices to the output power and efficiency of the power amplifier.Most of the power amplifier based on the wireless transmission research at home and abroad is the existing power amplifier products in the market.These power amplifiers are too expensive and the bandwidth is not pertinence.In order to reduce the cost of microwave wireless transmission and improve the power and efficiency of microwave wireless transmission,this paper mainly focuses on the research and production of RF power amplifier used in microwave wireless transmission.Firstly,the research status of microwave wireless transmission and RF power amplifier is analyzed.Then,the basic theory of RF power amplifier design is discussed.On the basis of comparing the common topology of several matching circuits,the matching structure of the mixed set total distribution element,which is more suitable for high frequency,is chosen as the basic topology of this matching network.So that we gan get better performance and debuggability.Secondly,on the basis of analyzing the demand of the microwave wireless transmission system,the design index of the power amplifier is determined.The power amplifier system is composed of ERA-6SM(the first stage),ADL5606(the driving stage)and NPT2021(the last stage)in the form of three level connection.The design steps of the power amplifier system are described in detail,and the S parameter model is used in the simulation design of the ADS radio frequency simulation software.The optimized tuning,and the method of iterate the input and output matching network into the load traction and the source traction medium,is used to optimize the design of the power amplifier matching network,so that the input network can be obtained as much from the input terminal as possible.At the 2.45 GHz frequency point,the output power and efficiency of the power amplifier are improved as much as possible.Finally,the power amplifier circuit which meets the requirements of the index is designed.At last,this paper uses Altium Designer software and ADS software to complete the PCB layout of the three level RF power amplifier,and uses SolidWorks software to complete the cavity design of the last stage RF power amplifier.The physical production of the amplifier is completed.Through repeated debugging and optimization,the output power of the RF power amplifier in the 2.45 GHz frequency point is higher than 30 W,the efficiency is higher than 40%,and the related test experiments are carried out in the microwave wireless transmission system,and the wireless transmission with good effect has been successfully realized. |
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