Numerical simulation for Ground Penetrating Radar wave propagation in the dispersive medium
频散介质中地质雷达波传播的数值模拟

The earth material probed by Ground Penetrating Radar(GPR) is often dispersive.To investigate the detecting capability of GPR in the dispersive medium,we propose a Finite Difference Time Domain(FDTD) method to solve Maxwell's equations.We give an iterative method for calculation of the electrical displacement and magnetic fields in the Debye medium,and a method to compute the electric field from electrical displacement.The physical parameters are used only in calculating the electric field.A new absorbing boundary algorithm is introduced by adding a fictitious dielectric constant and magnetic permeability,therefore the wave can be attenuated without reflection in the 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 the dispersive medium attenuates very fast and the measured signals are very weak.