Improved FDTD Method for Coupling Analysis of a Dielectric-Coated Wire Above Rough Soil Surface Under HPEM Pulse

An improved finite difference time domain (FDTD) method is proposed to calculate the transient coupling of a dielectric-coated wire above the rough soil surface under the high power electromagnetic (HPEM) pulse. The improved method is based on the domain decomposition technique, in which the dielectric-coated wire and the rough surface are allocated into the target subdomain and the rough surface subdomain, respectively. The reflected waveform from the rough surface is computed by applying the FDTD method combined with the time-domain Huygen's technique. The incident field on the target subdomain is calculated through the superposition of the excitation fields generated with the directly incident wave and the reflected wave from the rough surface. The near-field distribution and the energy-flux density (EFD) inside the dielectric-coated wire are simulated by running the FDTD in the target subdomain. The accuracy and high efficiency of the improved method are validated and demonstrated by comparing with the conventional FDTD method. Finally, the influences of some parameters related to the rough soil surface and dielectric-coated wire on the EFD are analyzed through the typical examples.