Shieldinf of ground penetrating radar antennas to reduce the influence of environmental noise and direct path communication for bistatic measurements

Abstract

This thesis investigates the performance and optimization of shield of ground penetrating radar antennas. The principle analytical tool utilized in the study is FEKO. The principally analysis proceeds in two phases; one where is chosen the best antenna for GPR and, the second one where is considered the single shielded antenna chosen (bow-tie antenna) with various combinations of shield configurations. The goal is to produce a radiation pattern with minimal back and side radiation to diminish the direct path communication and maximal radiation towards groun and therefore to obtain a good factor of shielding effectiveness. A paraboloid shield produced the best results in homogeneous and layered ground, although in this last case the improvements ar slightly appreciable. Simulations of the antenna in the far field indicate that the signal degrades as the soil changes, obtaining better results when it is homogeneous. Finally, to improve the results obtaines, other kind of antennas were developed obtaining that Yagi-Uda antenna offers the best characteristics and advantages.