Research On Waveguide Built-in Mode Converter

The waveguide built-in mode converter is an important passive transition device in radar,navigation,communication and other systems,which realizes the conversion of electromagnetic signals from waveguide to microstrip transmission and transmission mode from the waveguide main mode-TE₁₀0 mode converted to microstrip line master mode quasi TEM mode.Waveguide built-in mode converter has the characteristics of low insertion loss,high bandwidth,compact structure and flexible design,and its performance greatly affects the performance of the system.This paper focuses on the working principle and structural design of the waveguide built-in mode converter.The main work is as follows:The paper first introduces the research background of the subject,expounds the applicability of the subject,and lists several representative waveguide-microstrip line mode converters at home and abroad.Design method of three typical waveguide-microstrip mode converters are analyzed and studied.Secondly,the waveguide theory and microstrip line theory related to the waveguide built-in mode converter are introduced.The working principle and design structure of the waveguide built-in mode converter are studied,the design of the mode converter is given,theoretically illustrates the feasibility of this converter,the Design method and design steps of this converter is theoretically explained.Based on the principle of transceiving and reciprocity of the reference antenna,a conversion patch with a bandwidth of 1.16 GHz and a center frequency of 15 GHz is designed.According to the principle of frequency selection of the filter,a waveguide filter with good performance of 12 GHz to 16 GHz is designed,preliminary design of the waveguide built-in mode converter.Then analyze the physical parameters of the converter,study the influence of physical size on the performance of the converter,optimize the parameter data,the physical processing parameters are determined on the premise of processing accuracy.Through simulation test,the mode converter has a return loss of less than-10dB in the frequency range of14.62GHz-15.68GHz,the insertion loss is about-0.3dB and the bandwidth is about 1.06GHz.Finally,the physical object is processed,and the performance of the converter is tested by a combination of direct test and back-to-back test,and the simulation results are analyzed and compared to verify the correctness of the design.