Design of compact slot cavity backed Bow-tie antenna for GPR application

Abstract

GPR is a widely used technique for the detection of buried object such as land mines, water pipes, oil and buried pipes. This belongs to the family of nondestructive testing. GPR consists of multiple disciplines such as signal processing, image processing, modelling of GPR system and antenna design. Antenna plays a very important role in GPR system. Because GPR system’s efficiency largely depends on its antenna, the GPR antennas should have some specific characteristics such as UWB bandwidth for good resolution, low frequency of operation for high depth of penetration, high gain and high radiation efficiency for maximum power radiation, high directivity, etc. Bow-tie antenna is a widely used for GPR applications. In this research work, a cavity-backed compact slot Bow-tie antenna is designed having a bandwidth of 107% from the frequency range of 0.9GHz to 3 GHz. The ultra-wide band characteristics of antenna is achieved by applying different bandwidth enhancement techniques such as by optimizing the shape of the slot, by adjusting impedance of CPW feedline, and also by using taper slot for impedance matching between 50훺coaxial cable to the impedance of compact slot antenna. Since, the gain of Bow-tie antenna is low, cavity back technique is used to increase the gain. With ultra-wide band characteristics and significant improvement of gain over the operating band, the designed antenna promises improved system performance for a GPR system in the frequency range of 0.9GHz to 2.1GHz