Subsurface imaging is one of the challenging complex electromagnetic problems which requires a reliably sensor and effective signal processing algorithms. Problems vary from medical diagnosis (e. g., tumor detection) to the location of buried land mines, underground explosives, hidden headquarters, etc. Current investigations have focused on better antenna system design, signal waveform exploration, sensor integration, and intelligent signal processing methods. Numerical simulations in these areas offer great possibilities not only in understanding physical background of the problem at hand, but also in doing research in these challenging areas. We have developed a two-dimensional virtual tool (a simulation package) based on the well-known finite-difference time-domain (FDTD) method that can be used in simulations of variety of subsurface problems. In this presentation, the virtual tool will be used to generate synthetic data for the direct problem. Various ultrawide band (UWB) antenna array configurations with different time-domain signal waveforms will be reviewed. Finally, Subsurface Imaging (SSI) capabilities will be summarized as an inverse problem.