Ground penetrating radar (GPR) is an ultra- wideband electromagnetic sensor used not only for subsurface sensing but also for detection of objects which may be hidden behind a wall or inserted within the wall. Such applications of the GPR technology are used in military and civilian operations such as mine detection, rescue missions after earthquakes and investigation of archeological sites. Search for the presence of designated targets hidden between the walls, such as air pockets is help to archeologists. A two-dimensional (2-D) time-domain numerical scheme for simulation of ground penetrating radar (GPR) on dispersive and homogeneous soil is described. The finite- difference time-domain (FDTD) method is used to discretize the partial differential equations for time stepping of the electromagnetic fields. The soil dispersion is modeled by Lorentz model. The dispersive soil parameters are obtained by fitting the model to reported experimental data. The perfectly matched layer (PML) is extended to match dispersive media and used as an absorbing boundary condition to simulate an open space.