Time Domain Integral Equation Method Analysis Of Complex Target Transient Electromagnetic Scattering

Dispersive medium and random medium are widely used in the fields of military stealth technology,material science,bioelectromagnetics and microwave device design.It is of great significance to study the electromagnetic(EM)properties of such complex objects,and it will promote the theoretical development and technological innovation of related disciplines.Because of the complexity of the constitutive relation of the dispersive medium and the uncertainties of the electromagnetic parameters of the medium,the time domain integral equation method has always been the focus of scholars' attention on how to realize the accurate and efficient solution of the transient electromagnetic characteristics of the complex objects.In this thesis,the time domain integral equation method based on marching-on-in-time(MOT)scheme is applied to analyze the electromagnetic scattering characteristics of dispersive medium.In this scheme,time-domain recursive convolution for the dispersion medium can be simplified,because the unknown is the volume current rather than the electric flux density.Compared with the time-domain integral equation method,which uses the electric flux density as unknown,the method has the advantages of low memory consumption and short computing time.In addition,the analysis of engineering objects is complex,the method is then extended to analyze the electromagnetic scattering properties of those objects comprising perfect electrically conducting bodies and dispersive medium.A stochastic Galerkin(SG)time domain integral equation is proposed to analyze EM scattering from objects whose permittivity is uncertain in this thesis.The stochastic Galerkin method combines the time domain integral equation method based on marching-on-in-time(MOT)scheme and polynomial chaos expansion(PC)method.In this thesis,the transient EM scattering from composited metal and random media objects whose permittivity obey the Gaussian distribution and the uniform distribution,respectively,is studied.Compared with the Monte Carlo method,the SG method applied to analyze the transient EM scattering characteristics of random medium is more efficient.