A compact double-ridged horn antenna for ground penetrating radar applications

A compact double-ridged horn antenna for ground penetrating radar applications in the frequency range of 1–7 GHz will be presented in this work. Within this contribution the design, simulation and fabrication of such an antenna will be considered. Among the varying design parameters are linear and exponentially tapered walls as well as variations of the curvature of the dielectric waveguide between the two ridges. In addition an absorber structure and a complex shaped metallic back plate have been introduced to further improve the return loss. The primary design goal is a broad bandwidth while maintaining compact dimensions. Two modifications have been introduced in this antenna design in contrast to the standard TEM horn. By protruding the ridges from the aperture plane and filling the space between the ridges with dielectric material it is possible to lower the operating frequency without increasing the size of the original setup. The proposed design has been applied to subsurface radar application in both, field simulations by means of CST Microwave Studio and measurement in a GPR test scenario. The fabricated antenna has been verified by anechoic chamber measurements. The performance of the antenna with respect to the detection of subsurface objects will be verified by various experiments.