A Compact Coplanar Broadband Rectangular Slot Antenna with E-Shaped Feeding Structure for GPR Applications

A coplanar rectangular slot antenna operating in the very wide frequency band from 0.27 to 3.1 GHz (bandwidth over 166%) has been designed for GPR applications. The antenna, which is supposed to be positioned on the soil surface, appears particularly compact (34 x 29 cm) and exhibits a low cross-polarization in the E-plane. 3D FDTD simulations have allowed to make a detailed parametric study associated with the antenna dimensional parameters in order to optimize the radiating performances. The slot antenna has also been studied with a shield to be further integrated in a bistatic subsurface radar positioned on the soil surface. Simulated results of the link in the presence of a homogeneous soil then including buried objects met in civil engineering structures are presented and discussed. First experimental results on a sandy soil have been compared to numerical ones.