Wide Band Antenna for Ground Penetrating Radar (GPR)

High gain and wide bandwidth are the two antenna parameters to be considered for deep penetration in GPR applications. A cavity-backed bow-tie antenna at 850 MHz has been proposed for Ground Penetrating Radar (GPR). A metal cavity has been installed to achieve a unidirectional radiation pattern, wide bandwidth, better isolation, and high gain. Glass epoxy (εr=4.3, loss tangent=0.025) has been used as a substrate material, which is less lossy at this frequency. The proposed antenna yields a bandwidth of 105.88% (0.4-1.3 GHz) for |s11| ≤ -10dB and a minimum isolation of 23 dB between two such antennas for the separation of 0.113λ (λ =free space wavelength). The antenna has a maximum gain of 14 dBi and radiation efficiency greater than 90% over the entire bandwidth. The antenna has been designed using CST microwave studios and fabricated. The measured results are in good agreement with simulated results.