Accounting for multiple reflections and antenna radiation pattern in gpr signal modeling and experimental validation

This paper presents an accurate model of a monostatic stepped-frequency continuous-wave (SFCW) ground-penetrating radar (GPR). The model takes into account the multiple reflections occurring between the soil, target and antenna, which are a transverse electromagnetic (TEM) ultra-wide band (UWB) horn. Two equivalent current distributions representing the antenna radiation pattern are considered: a dipole of electric current located at the phase center of the antenna, and a Huyghens cosinusoidal distribution of electric and magnetic current located on the aperture. The model is validated by experiments, for which the targets are embedded within increasingly complex backgrounds: in free space, above a metal plane, and finally buried in a sandbox. These experiments validate altogether the radar modeling, as well as the MoM and the dyadic Green's functions (DGFs) used in the numerical algorithms.