An UWB ground-coupled radar has been designed to operate from 460 MHz to beyond 4 GHz and essentially for civil engineering applications. Full-wave modeling using the FDTD approach has allowed to study in details the antenna radiation characteristics in air, in the presence of a soil and as a constituent in a bistatic GPR system. The polarization diversity in the E and H-planes is an important aspect which has been studied in order to further detect the orientation of damages (cracks or delaminations) in civil engineering structures. The analysis of the hyperbola signatures has allowed to evaluate the ability of the radar to detect small canonical buried objects.