A Fast Algorithm For Wide-band Electromagnetic Scattering From Rotationally Symmetric Bodies

The research of analyzing the electromagnetic scattering from electrically large targets with high efficiency has been an important topic in the field of computational electromagnetics.The body of revolution(BoR)has always been widely concerned because of its special geometry.When using the time domain Method of Moment(MoM),the spatial discretization only needs to be carried out on its generatrix.The high-order spatial basis functions are used in this thesis with larger split size and fewer unknowns,thus higher efficiency can be obtained.The parabolic equation(PE)is an approximation of the wave equation.Compared with the integral method,the PE method costs less computational resource with lower accuracy.When analyzing the BoR,the PE method can be simplified according to the field distribution,thus the computational resources will be significantly reduced.A fast algorithm for the time-domain electromagnetic properties of BoR is studied in this thesis.Firstly,the special characteristics of BoR are presented and then the basic theory of the time-domain integration method for the BoR is introduced.The first-order,second-order and third-order curvilinear basis functions are introduced for the spatial subdivision of BoR.Then the time-domain integral equations based on these basis functions for PEC and dieclectric BoRs are derived in detail.What's more,the adaptive cross approximation(ACA)method is adopted to further reduce the computational memory requirement.At last,the PE method for PEC BoR is derived in a marching manner.As we all know that the field around the rotational symmetric body can be expanded into the Fourier series.In this way,the standard three-dimensional PE can be simplified to a series of one-dimensional problems.As a result,both the CPU time and memory requirement will be saved greatly.