Research On RCS Reduction Based On Artificial Electromagnetic Structure

With the use of electromagnetic technology in warfare and the continuous development of radar detection technology,electromagnetic stealth has been valued by many countries.Whether it can achieve stealth in combat,to a certain extent determines the survival probability of combat weapons,so how to reduce the target radar cross section(RCS)has important research significance.Artificial electromagnetic structure,or metamaterial(MTM),is an artificial material with different physical properties from natural structures.In recent years,the target RCS reduction has been widely used.In this thesis,based on electromagnetic wave absorption and electromagnetic wave passive cancellation,two kinds of novel artificial electromagnetic structures(AESs)are designed,they are multi-frequency absorbing structures based on resonance characteristics,and a chessboard structure constructed by two artificial magnetic conductors(AMC)with a reflection phase difference of 180°..These structures achieve the target RCS reduction in multiple bands or a wide band.The following is a brief introduction to the main content of this thesis.In the first chapter,the research status of artificial electromagnetic structure(AES),including its application in RCS reduction and absorbing structure,is introduced.Besides,two methods of increasing the absorption bandwidth of absorber with resonance characteristics,and the background and significance of the research work are summarized.The second chapter is mainly about the introduction of basic theories,including the basic theory of AES,the theory of electromagnetic absorbing and the related theory of RCS reduction.The relationship between the absorbing rate of AES and the reduction of RCS are summarized.In the third chapter,four multi-frequency metamaterial absorbing structures are designed,which are the double-nested absorber(DNA),triple-nested absorber(TNA),three-layered-superimposed absorber(TLSA),and double-layered-superimposed double-nested absorber(DLS-DNA)based on AES.Their S-parameters,electrical resonance characteristics and energy absorption characteristics,as well as the influence of structural parameters on the performance of the absorbing structure are analyzed.In the fourth chapter,four 2×2 array absorbers based on AES are analyzed.The main contents include two aspects,namely the energy absorption characteristics and the RCS reduction characteristics of the absorbers.In the fifth chapter,two new AMC structures are designed.Firstly,reflection phases of AMC units are adjusted and analyzed.After the AMCs are determined,the AMC chessboard structure is constructed on the basis of the AMCs.The broadband RCS reduction characteristic of the chessboard structure is verified,then the reason for the reduction in RCS was analyzed.In the last chapter,the work of the full text is summarized,and the deficiencies in the current work is discussed,and the future research is prospected.