A Decent Step Method Based On The Order Of Time-domain Integral Equation Method

For a long time,frequency domain algorithm is the key computational method in computation electromagnetic field with the increase of the engineering applications of high resolution short time pulse radar,target identification,broadband signals modeling and non-linear systems.Time domain method has aroused wide attention of many scholars. Compare with frequency domain algorithm,the time domain method have many unparalleled advantages in analyzing transient electromagnetic scattering and radiation problem. Time domain integral equation is one of the time domain algorithms, therefore, to study time-domain integral equation is of great significance.However, because of its oscillation in late time, the conventional marching-on in time (MOT) method develops slowly. The Marching-on-in-Order (MOO) algorithm for the time-domain integral equation, which has no late-time instability, therefore, has broad prospects for development.In testing procedure, the conventional marching-on in time (MOT) technique uses Galerkin's method in spatial and point marching method in temporal, whereas the solution method in this paper is based on the Galerkin's method both in spatial and temporal.RWG basis functions are used for spatial expansion and testing functions for the metal target. SWG basis functions are used for spatial expansion and testing functions for the dielectric target. The time-domain unknown coefficient is approximated by using a set of orthogonal basis functions that are derived from the Laguerre functions. These basis functions are also used as temporal testing.In this article,transient scattering by conducting surfaces of arbitrary shape was firstly analyzed by the MOO algorithm based on time domain surface integral equation. Then transient electromagnetic scattering of non-uniform dielectric was analyzed by the MOO algorithm based on time-domain volume integral equation. Finally, we use the time domain volume-surface integral equation to analyze transient electromagnetic scattering of metal-dielectric composite target. Numerical examples are given to show the correctness and accuracy of all the above methods.The research work presented in this dissertation provides an efficient approach to analyze transient electromagnetic scattering of complex targets, as well as a firm foundation for the further development in this subject.