Accurate and efficient FDTD modeling of ground-penetrating radar antenna radiation

We present a 3-D finite-difference time domain (FDTD) solution of Maxwell's equations for modeling the near-field radiation of dipole antennas 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. Integration contours and surfaces are defined by the finite-difference cells surrounding the wire. Everywhere else the electromagnetic wavefield is calculated using conventional FDTD approximations of Maxwell's equations. The accuracy of the algorithm has been tested by comparing the simulated near-field radiation of a dipole antenna between two dielectric media with corresponding experimental observations.