Numerical modeling and characterization of fully polarimetric dielectric loaded horn-fed bow-tie (HFB) antenna for GPR applications usingFDTD

Antennas for Ground Penetration Radar (GPR) applications have stringent specifications in terms of wide bandwidth, no antenna ringing, and input impedance matching. In order to penetrate deep enough in lossy ground soils and in applications associated with detection and classification of Unexploded Ordnances (UXO) or land mines, i t is common to have operating frequencies i n the range from 10 MHz to 800 MHz. One of the most popular ultra wide band (UWB) antennas for GPR applications is the bow-tie dipole element. TO achieve a better stability over the ground surface and a better efficiency into the ground, a fully polarimetric dielectric loaded Horn-Fed Bow-tie (HFB) antenna has been recently developed [l] , [2]. BeCause of the compact size of this UWB HFB antenna, reflections from the end of the antenna a n s , which cause late time ringing effects and energy backflow into the feed line at the end of the arms. can occur. To prevent this undesired phenomena, resistive cards[3] are attached to the antenna arms. The resistive cards have a properly chosen conductivity profile :o minimize any reflections. Moreover, to achieve good input impedance matching over the whole bandwidth, the feeding structure also needs to be carefully considered