<title>Evaluation of the half-space dyadic Green's function for the buried object problem</title>

Abstract

The imaging of buried objects poses the need for a dyadic Green's function for a medium stratified into above- and below-ground spaces. The perturbation field due to the existence of the object is as if radiated by equivalent currents. An integral equation is written in which the unknown is the current density. For solution by the Method of Moments, the current distribution is approximated as the weighted sum of a a set of basis functions. The Distributed Source (DS) Dyadic Green's Function is introduced to relate the vector field and basis function of directed current. This study is concerned with numerical evaluation of the DS Green's function. The function has been derived in the form of a doubly infinite integral of which the integrand contains a line singularity. In some cases evaluation of the integral presents problems of convergence. The infinite integration area has been made finite by a particular choice of basis functions. The line singularity has been eliminated by exploiting the convolution theorem. The convolution integrand contains a simple singularity which disappears under a change of variables. The DS Green's function has been evaluated without numerical difficulty. Values agree with those calculated by other methods where available.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.