Time-domain Electromagnetic Scattering Analysis Of The Rotationally Symmetric Body

The method to calculate time-domain wideband electromagnetic scattering of electrically large targets has been in urgent demand, since the development of ultra-wideband, target recognizing and SAR. The usage of the axisymmetric property of the body of revolution (BoR) can translate an original electrically large BoR-problem into a series problems with small size of matrix equations, namely a Fourier mode of the original one, which can greatly improve the computational efficiency and reduce the memory requirements. In this thesis, on the basis of frequency-domain method of momemt of BOR, we develope time-domai integral equations to calculate the time-domain electromagnetic scattering of BOR.This paper mainly researches time-domain electromagnetic scattering from pefect electric conductor bodies of revolution in free space. Time-domai electric and magnetic integral equations are formulated via Maxwell's equations, potential functions, equivalent principle and the boundary conditions.With the rotational symmetry, the spatial element of unknown equivalent electric currents can be expanded in Fourier series in (?) and sectional function in t.And the temporal element of unknown equivalent electric currents can be expanded in weighted lagurre polynomials. Gaussian plane wave is used as the incident field in this paper, it has finite frequency that is propitious to get the fast convergence.Basis functions and testing functions have been choosed, which were applied to the time-domain integral equations. Then we use the spatial and temporal testing scheme to the equations. By using the dispersive method,we get the matrix equation. A solution of each Fourier model matrix equation is solved by the marching-on-in-order procedure, then we get the time-domain equivalent electric currents of one Fourier model.Because each mode is orthogonal to the others, the problem can be solved under each mode respectively and each solution is summed up subsequently. Thus it reduces greatly the sum of unknown variable and the calculational time.The number of the order and the Fourier component which is variable is further studied in this thesis.We discusse the method to truncate the number of the order and the Fourier component and the effect of the variable.