ACCURATE AND EFFICIENT FDTD MODELING OF GROUND-PENETRATING RADAR ANTENNA RADIATION

We present a 3-D finite-difference time domain (FDTD) solution of Maxw ell's equations for modeling the near-field radiation of dipole antenn as in ground-penetrating radar surveys. The antenna is represented as a conducting wire with a narrow gap in the middle. The electromagnetic field in the immediate vicinity of the wire is evaluated by numerical solution of an integral representation of Maxwell's equations. Integr ation contours and surfaces are defined by the finite-difference cells surrounding the wire. Everywhere else the electromagnetic wavefield i s calculated using conventional FDTD approximations of Maxwell's equat ions. The accuracy of the algorithm has been tested by comparing the s imulated near-field radiation of a dipole antenna between two dielectr ic media with corresponding experimental observations.