Optimal Design Of Multi-frequency And Broadband Coaxial Feed

Coaxial feed has been widely used in reflector antenna system because of its compact structure and excellent performance.Aiming at the requirements of broadband and multi frequency feed network system in the fields of satellite communication,electronic countermeasure,remote control and telemetry,this paper deeply studies the fast calculation and optimization design method of coaxial feed,and realizes the optimization design of broadband and multi frequency coaxial feed.In order to solve the problem of poor impedance matching after cascading coaxial feed and microwave network,the integrated optimization design technology of feed network is studied,which effectively improves the performance of feed network.Firstly,a fast calculation method of coaxial feed based on method of rotating body finite difference time domain is proposed,which improves the efficiency of feed system analysis.In order to realize the integrated design of feed and reflector system,a analysis method of radiation characteristics of coaxial feed is given based on the efficiency factor method.Through the analysis and calculation of typical design cases,the effectiveness of the above method is verified.Combined with high-performance optimization algorithm,a coaxial feed optimization design method is proposed,which lays the foundation for the subsequent coaxial feed optimization design.Next,according to the requirements of reflector antenna for broadband and wide beam feed,a new broadband coaxial feed structure is proposed.A fast analysis and optimization design model of broadband coaxial feed is established,and a broadband coaxial feed working in L-band is designed.The feed prototype is manufactured and tested.The simulation results are in good agreement with the measured data,which verifies the feasibility of the optimization design method.Then,aiming at the problem that the high and low frequency channels of Ku/Ka coaxial feed have great influence on each other and the feed performance index is limited,the Ka band waveguide size is compressed by using dielectric loading technology,and by introducing multi impedance matching structure,two kinds of Ku/Ka coaxial feed structures are given and optimized.The simulation results show that the optimized coaxial feed has compact structure and excellent performance.Finally,in view of the problem of poor impedance matching after cascading coaxial feed and microwave network,the cascading simulation and optimization design are carried out,which improves the performance of feed network system and realizes the integrated design of feed network system.The prototype of Ku/Ka feed network system is processed and tested.The measured results are in good agreement with the simulation results,and the feed indexes meet the design requirements.