Research And Design Of Spaceborne "Push-broom" Offset Ring-focus Paraboloid Antenna

As an important part of the payload of high resolution sea surface temperature,salinity and wind detection satellite,reflector antenna has an important influence on the performance of the whole detection system.In view of the problem that the traditional single-feed reflector antenna cannot meet the irradiation demand of the system,the research on the "push-broom" offset ring-focus paraboloid antenna fed by dense feed array has attracted more and more attention from scholars.The design of paraboloid determines the spatial resolution and observation width of the system,while the design of dense feed array and beam optimization determine the offshore detection distance of the system.Therefore,the antenna design must consider the system performance,hardware cost and application requirements.The research of spaceborne "push-broom" offset ring-focus paraboloid antenna mainly includes the following aspects in this paper:1.The "push-broom" ring-focus paraboloid is studied.Aiming at the application background of scientific research projects,the toroidal reflector from L to Ka band is designed,which is as close as possible to the standard paraboloid when determining the parameters such as focal-diameter ratio and feed offset height.At the same time,in order to realize conveniently in engineering and not affect the performance of the antenna in large angle scanning,the designed parabolic edge is filleted.2.The dense feed array is studied.The arrangement and number of feeds in the dense feed array at different frequency bands are analyzed,and the feed array required for forming a single beam is determined.For the optimization of amplitude and phase coefficient of feeds,this paper proposes an optimization algorithm of dense feed array based on genetic algorithm.This algorithm is based on genetic algorithm,and takes into account the selection of weight value and optimization objectives in the optimization of directional diagram.Based on this algorithm,the amplitude and phase weighting optimization of the feeds corresponding to different scanning angles is carried out by using GRASP,MATLAB and HFSS co-simulation,and finally the pattern that meets the requirements of the system index is obtained.3.The optimization scheme of amplitude and phase weighting coefficient of dense feed array based on the most simplified feed network is determined.In order to realize ±35° beam scanning in the intersection dimension,this paper proposes an optimization scheme of amplitude and phase weighting coefficient of the feeds based on the simplest feed network.Finally,in the intersection dimension,only two sets of weights are needed to obtain the pattern that meets the requirements of the system,which greatly simplifies the design of the feed network.4.An X-band "push-broom" offset ring-focus paraboloid antenna prototype is developed.Firstly,the amplitude and phase coefficients of the X-band dense feed array are optimized by the feed optimization algorithm,and the design of the one-point forty eight Wilkinson power divider network is completed by the optimized amplitude and phase values.Secondly,the overall projection size of the antenna is 245.8 mm × 460.7 mm,the focal-diameter ratio is 1.3,the feed irradiation angle is 40° and the feed offset height is 107 mm.Finally,the prototype is processed and tested in the microwave anechoic chamber,the measured results are in good agreement with the simulation results,and the technical indicators meet the design requirements.