Numerical simulation for ground penetrating radar in dispersive medium

摘要

The earth material probed by Ground Penetrating Radar (GPR) is often dispersive. To investigate the detecting capability of GPR in dispersive medium, we introduced a Finite Difference Time Domain (FDTD) method to solve Maxwell's equations. We give an iterative method for electrical displacement and magnetic field in Debye medium, and a method to compute electric field from electrical displacement. The physical parameters are used only in calculating electric field. A new absorbing boundary algorithm is introduced by adding fictitious dielectric constant and magnetic permeability therefore the wave can be attenuated without reflection in absorbing layer. This method overcomes the troublesome caused by field split in Berenger's Perfectly Matched Layer (PML), so that the computing efficiency is increased. Examples demonstrate that the electromagnetic wave in dispersive medium attenuates very fast and the measured signals are very weak.