Underground target probing using FDTD

Great interest has been paid to the detection and characterization of subsurface radar targets. Most results were obtained using quasi-ideal conditions due to the complexity of the problem. If the medium in which the target is embedded is inhomogeneous or contains other scatterers, analytical methods fail to predict the scattered field. Furthermore, the most interesting quantity that can be measured is the near field since the detector must be placed as close as possible to the air-ground interface. Another problem is the fact that the electrical size of the targets is usually equal to or smaller than the wavelength inside the medium. The finite-difference time-domain method is very well suited to this particular application because complex geometries may be treated without increasing the computational burden. This paper shows how the FDTD method can be used to model the field scattered by canonical subsurface targets. A UHF dipole detector is also included in the model.