High-resolution ground-penetrating radar (GPR) evaluations of structures are usually carried out using antennas with high nominal centre frequencies (between 1 and 2GHz). A comprehensive characterization of such an antenna would make it possible to determine the capabilities of a system and obtain accurate data interpretations. This paper describes the experimental determination of the radiation pattern of a commercial 1.6 GHz antenna, which forms part of a comprehensive experimental characterization. Radiation patterns are closely related to spatial resolution, so the horizontal and vertical resolutions are evaluated first. The footprint of the antenna is then measured in air using simple devices at different distances. The final result is the approximate spatial radiation pattern of the emitted energy, measured in air. Finally, these measurements are also taken in sand to obtain the radiation pattern and footprint of the antenna in this medium.