Multi-Frequency Gpr Surveys

Ground penetrating radar (GPR) antenna selection must be based on specific survey objectives. The choice of<br>antenna is primarily a compromise between resolution and depth of penetration. This paper briefly presents three<br>case histories of multi-frequency GPR surveys that explain and illustrate how the antenna and the electromagnetic<br>(EM) properties of the ground affect wavelength, loss mechanisms, far-field radiation, and the near-field. Changes in<br>these parameters are important because they affect vertical and horizontal resolution, and depth of penetration. In<br>general, when the depth of penetration is limited by conductive losses instead of scattering losses, changing to a<br>lower-frequency antenna will not help in detecting shallow features, and may not help in detecting deeper features.