oa Finite-difference modelling of ground-penetrating radar data: antenna radiation patterns

We present a FDTD algorithm to model the near-field radiation characteristics of dipole antennas. The antenna is represented as a wire with a small gap in the middle. The initial condition is given by a time-variable voltage pulse fed into the central gap in the wire. The resulting E-field in the gap can be calculated analytically, whereas the E- and H-fields in the vicinity of the wire are evaluated by numerical solution of an integral representation of Maxwell's equations. Integration contours and surfaces are defined by the cells surrounding the wire.