Research On Mode Purification Technology Ofhigh Power Transmission System

High frequency and high Power Microwave（HPM）transmission and feeding systems generally need to transmit and transmit high-power electromagnetic signals in specific working modes.However,multiple modes may be established during the transmission of electromagnetic waves in guided wave systems,reducing the purity of electromagnetic signals transmitted in specific modes.As a result,the local electric field intensity of the transmission and feed system increases,which affects the power capacity of the whole transmission and feed system.In order to meet the requirements of specific power capacity and transmission mode,it is necessary to adopt mode purification technology to improve the purity of specific mode output of transmission system.Generally,the high order mode suppression and high mode conversion efficiency can be achieved through the structural design of high power microwave transmission feed system.This paper focuses on the theoretical analysis,structural design and simulation of the mode converter for the mode purification technology of the axis bending mode converter.The main contents of this paper are as follows:In this paper,an axis bending TE_11-TM₀₁mode converter is proposed,which has high mode conversion efficiency and power capacity,and the requirement of machining accuracy is reduced.In this paper,the realization principle of axis bending TE₁₁-TM₀₁mode converter is given,and the method of mode converter is studied by changing the transmission path of signal through the metal plate structure,so that it can meet the phase difference condition of mode conversion.The effect of changing the parameters of bendy TE₁₁-TM₀₁mode converter on the efficiency of TE₁₁-TM₀₁mode conversion is analyzed.At the same time,this paper proposes a method to reconstruct the magnetic field distribution of the output signal of the mode converter by inserting a cruciform metal insert in the output end,so as to improve the purity of the output mode.The purification ability of the cruciform metal insert for the high-order mode TE₂₁mode is analyzed.Then,according to the above research conclusions,an improved TE₁₁-TM₀₁mode converter with wide band and high power capacity is proposed by optimizing the internal structure of the mode converter.Finally,aiming at the requirement of High Power capacity,we designed the broadband HPM（high-power Microwave）bending TM₀₁-TE₁₁mode converter with metal insert plate of"Snowflake"structure to achieve high power capacity and mode purification.