Time Domain Hybrid Method Applying On Electromagnetic Scattering

In this paper, the derivation of equation process of Time Domain Integral Equation (TDIE) method be provided for analyzing transient scattering of thin wire. From source Maxwell equation and the thin wire approximation, the differential-integral equation of arbitrary structure thin wire electromagnet response has been derived. According to the helical antenna and conical spiral antenna, the effects of transient response for changing antenna parameters are discussed when two polarization wave incident.A novel hybrid method combining time domain integral equation (TDIE) with finite difference time domain (FDTD) is proposed to calculate transient response of thin wire structure above a lossy layered half space. The time domain reflections of electromagnetic waves from layered half space are obtained by one dimensional FDTD method. Then, transient response of thin-wire induced by two excitation sources (the incident wave and reflected wave) is achieved by employing TDIE. Related calculation theory and numerical simulation results indicate that the method presented in this paper is high efficient solution for calculating the transient response of thin wire above layered half space.Furthermore, the time-domain reflection of the layered half space is computed by one-dimensional modified FDTD method. Then, transient response of thin-wire induced by two excitation sources (the incident wave and reflected wave) is calculated by TDIE method. In oblique incidence, the presented scheme can efficient calculate the transient response of thin wire above a lossy layered half space.The TDIPO be enhanced by time-domain equivalent edge current (TDEEC) to further determine the far-field characteristics of the combinative target with rough surface. An accurate composite geometry model technique which combines2-D perfectly electrically conducting (PEC) rough surface and half-buried3D PEC target is introduced and employed to assistant with the meshing work. The validity of presented method is verified by comparing the scattering results for dihedral targets with those obtained through TDPO and finite difference in time domain (FDTD), as well multi-level fast multiple algorithm (MLFMA). Then simulations of EM scattering from the target embedded in rough surface for different incidence directions are carried out to test the availability of TDIPO/EEC. Discussions on the effects of incidence direction and the presence of the target on the backscattering in far-zone are also given.