Design of a low cost cavity backed wideband bow-tie antenna for ground penetrating radar systems

The ground penetrating radar (GPR) designs demand antennas with ultra wide bandwidths (UWB). Thus the conventional antennas such as dipoles cannot be used effectively. The GPR antennas are expensive. In this paper, the feasibility of building a low cost ultra-wide band bow-tie antenna for GPR using widely available low cost materials such as FR-4 PCB substrates, low cost TV baluns and scrap iron is explored. The objective was to develop the antenna to radiate in the range from 200 MHz to 600 MHz whilst restricting the antenna lobes to the direction of the ground. A cavity backed design is considered to obtain these requirements. The antenna was modeled using Ansoft HFSS (presently Ansys HFSS) software package which is widely used in current industrial domain. The simulations were carried out for different antenna configurations by changing its parameters according to linear programming techniques. Further, electromagnetic interferences (EMI) have been successfully reduced by integrating a metal cavity which acts as a reflector to the antenna. Parameters related to the cavity were tweaked in order to obtain the optimum frequency response. Considering the simulation results the most satisfactory antenna configuration was obtained and implemented.