Research On Broadband High-Power Horn Feed Technology

High-power broadband feed is a key equipment in high-power millimeter wave transmission systems.In order to achieve high-efficiency radiation to the energy of broadband high-power source,the feed should be able to generate an ideal beam of radiation with the characteristics of high-power capacity and wide bandwidth.Therefore,this thesis summarizes the entire process of the smooth-wall horn feed from the excitation source to the output radiation beam,and discusses the design method of the smooth-wall horn feed in detail.The proposed design method consists of two parts:the port mode design method for any radiation beam and the inverse optimization algorithm for the smooth-walled horn feed.In order to generate a specific radiation beam,the output port mode should first be designed.Different types of radiation beams have different requirements for port modes.For high gain feeds,the port mode should have a specific proportion of TE_1x mode combinations;For feed sources with stable radiation fields,this topic proposes two design methods:phase modulation method and field decomposition method,which improve radiation field stability by introducing mode phase difference and higher-order mode,respectively,and provides corresponding port mode calculation methods;For the radiation field of the specified gain curve,the required port mode conditions can be obtained through inverse optimization.In order to achieve the desired mode coupling of the smooth-wall horn feed,this topic improves the inverse optimization algorithm based on mode matching theory.Traditional inverse optimization algorithms have poor optimization ability and slow optimization speed,and are not suitable for large oversized horn feeds with high power capacity.This topic decomposes the optimization steps through parameter discretization,simplifies the optimization space,and greatly improves the optimization efficiency of the optimization algorithm by establishing a database.Based on this optimization algorithm,this thesis has designed four types of smooth-wall horn feeds with different radiation beams,all of which have the desired radiation beams and have a wide bandwidth,demonstrating the effectiveness of the smooth-wall horn design method proposed in this thesis under different frequencies and different requirements.