Design And Research Of Multi-Band Feed System

As an indispensable field of mobile communication,satellite communication has a long history and broad application potential.Among them,the reflector antenna has been one of the most widely used antenna forms in satellite communications because of its strong points of high gain,large power capacity and stable structure.Common single reflector antennas are divided into feedforward reflectors and offset reflectors.In recent years,systemization,multi-band,and miniaturization have gradually become the main research trends of reflector antennas.The multi-frequency band of the reflector antenna is actually the multi-frequency operation requirement of the feed system.Based on this,this article takes the multi-band design of the feed system as the research goal.The following is the main work of this article:1.The development history and principle explanation of the reflector antenna.First enumerate the development of reflector antennas throughout the world and related research progress.Since the application scenario of this article is the offset reflector antenna,the next focus is to analyze its optical characteristics.Then it briefly describes the composition framework of the feed system,and presents the corrugated horn,frequency divider,orthomode transducer,circular polarizer and waveguide filter in terms of performance indicators,basic principles,and common types.2.Research on multi-band feed horn.After explaining the basic principles of corrugated speakers working in multiple frequency bands,firstly introduces the strengths and weaknesses and application scenarios of traditional straight-groove loaded corrugated horn.Then a triple-slot loaded chute corrugated horn applied to an offset reflector antenna was proposed.Compared with the straight-groove loaded corrugated horn,the improved horn has a wider irradiation range.The introduced triple-slot deep corrugated grooves work in different frequency bands,and the irradiation angle of 30° can still be maintained when the frequency multiplication ratio reaches 3.75.The edge illumination level is between-12 d B and-18 d B,which ensures the illumination efficiency of the feed.After that,the design and analysis of the two corrugated horns were compared,verifying the validity of the design.3.The design of X and K band feed system.According to the design and actual engineering requirements,two feed systems working in X and K bands were designed.The key component is the design of the same frequency orthomode transducer.Thereafter the corrugated horn,circular polarizer and other transition components were simulated and tested.Finally,the two feed system and the actual required reflector antenna were jointly simulated to verify the overall design.4.Research on C/X/Ku triple-band feed system.First,the index requirements and working methods of the triple-band feed system are displayed,and then the principle analysis and simulation design of the frequency divider,the core component of the system for multi-band operation,are put into effect.The four-wall symmetrical coupler structure was chosen to avoid excitation of higher-order modes.Considering the large frequency multiplication ratio and the size of the feed system,quarter cut processing was performed during the simulation process,and the complete model was simulated by setting the symmetrical boundary.Then the design of the feed network,including turnstiles,waveguide bends,power dividers and combiners,waveguide filters,and transition devices,was implemented,and then the overall simulation was carried out with the triple-band feed horn.Finally,the feed system and the reflector antenna are jointly simulated,and the results show good performance concerning the transmission and radiation performance of the feed system.