Research On Characteristic Mode Analysis Of Electromagnetic Scattering

The characteristic mode analysis was first proposed by studying the radiation and scattering of metal target.In recent years,with the rapid development of computer,the research on characteristic mode analysis has slowly attracted more and more scholars.Because the characteristic mode analysis is only related to the inherent properties such as the structure,material and size of the electromagnetic target,and has nothing to do with other external excitation sources,taking the characteristic mode analysis as the starting point to study the electromagnetic scattering and radiation characteristics of the target can clearly reveal the physical mechanism of electromagnetic scattering and radiation of the target.This paper mainly studies and verifies the characteristic mode analysis method of metal and dielectric target.Firstly,starting from Maxwell’s equation,combined with scalar potential and vector potential function,the electric field integral equation is obtained.On this basis,the generalized eigenvalue equation is obtained from the perspective of mathematical operators and energy by using the method of moments,and the physical meaning of characteristic mode is explained.The eigenvalue and characteristic current and other related parameters are obtained from the solution of the generalized eigenvalue equation.The characteristic mode analysis method is used to calculate and verify the electromagnetic scattering of metal target in free space,and the radar cross section of the target is effectively extracted,which shows the correctness of this method.Aiming at the electromagnetic scattering environment in half space,the characteristic mode analysis method of electromagnetic scattering characteristics in half space is studied.The characteristic mode of metal target is calculated and analyzed through the mixed potential electric field integral equation in half space,the characteristic current and induced current are extracted,and finally the radar scattering cross section distribution is obtained.Secondly,the characteristic mode analysis method of electromagnetic scattering characteristics of dielectric targets is studied.The characteristic mode analysis method and numerical solution of dielectric structure target are described,with emphasis on the characteristic mode analysis of PMCHW formula based on surface integral equation.Because the impedance matrix of PMCHW equation is asymmetric,a symmetry correction scheme is introduced to convert the matrix into a symmetric matrix to solve the eigenvalue equation.A complex scalar factor is introduced to multiply the submatrix,and the asymmetric PMCHW complex matrix equation is transformed into a symmetric form.The reduced matrix equation about the surface current is obtained by using the Gaussian elimination method.The real part and imaginary part of the reduced matrix equation are separated,and the generalized eigenvalue equation about the surface current is established.The scattering coefficient of the metal cross-section is calculated by using the method of the excitation mode of the medium,and then the scattering coefficient of the metal cross-section is calculated.Finally,the correctness and effectiveness of this method are verified by analyzing the electromagnetic scattering characteristics of several different targets.