Electromagnetic detection of buried dielectric targets

Scattering from subsurface objects is studied using the T-matrix method. The scatterer is represented by a dielectric ellipsoid, and the source is assumed to be an electric dipole in a borehole. This approach accommodates rotations of the scatterer relative to the source and also permits relaxation of the two-dimensional constraint inherent in some models. In addition, it provides a framework within which a large number of subsurface scattering problems can be studied. To illustrate how this approach can be applied, the fields scattered from highly eccentric ellipsoids are found. In addition, polarization results demonstrate that a method based on the polarization of the scattered field may provide a more robust diagnostic of scatterer location than methods using only a single field component. An experiment based on a scale model of a subsurface tunnel is described. Results from the analytic model compare favorably with those obtained from the experiment