Microwave Subsurface Crosswell Imaging using Finite Difference Frequency Domain Modeling

We have developed a new algorithm for electromagnetic inverse scattering problem in inhomogeneous media using finite difference frequency domain (FDFD) forward modeling, referred as FDFD-based inversion method. The key issue of this method is to build a linear expression for the inverse problem from the FDFD forward modeling by using the Born approximation. An important advantage of this matrix-based method is that there is no need to specify a Green's function. This inversion algorithm is applied to microwave subsurface object detection using cross well radar. The new method is compared with the conventional inversion using Green function-based Born Approximation (GFBA). This EM scattering inverse algorithm is easily implemented and is robust to the heterogeneity of background. Numerical experiments are presented for a two dimensional borehole geometry for buried object detection in soil.