**Authors:** Constantinos A. Valagiannopoulos, Nikolaos L. Tsitsas, and Ari H. Sihvola

**Source:** FERMAT, Volume 20, Communication 13, Mar-Apr., 2017

**Abstract:** A ground-penetrating radar (GPR) antenna excites a perfectly electric conducting (PEC) inclusion buried inside the ground. One of the main problems in the detection of the PEC inclusion via external measurements is its poor scattering response due to attenuation. Hence, increasing the scattered power generated by the inclusion is of great practical interest. To this direction, the main purpose of this work is to investigate a procedure of unlocking the ground by depositing a thin passive layer of conventional material atop of it. The first step of the developed methodology is to significantly enhance the transmission into a lossy half space, in the absence of the inclusion, by covering it with a passive slab, the thickness and permittivity of which are to be determined. Then, the full boundary value problem (including the inclusion) is solved semi-analytically via integral equations techniques. The scattered power of the buried inclusion is compared to the corresponding quantity when no additional layer is present. Results from numerical simulations are presented exhibiting the effectiveness of the approach. Substantial improvement in the detectability of the inclusion is reported for several types of ground and burying depths by using conventional realizable passive materials. The effects of the shape of the buried inclusion on the scattered field are also investigated. The developed technique may constitute an effective configuration (structural) preprocessing which may be used as an initial step in the analysis of related problems before the application of an inverse scattering algorithm concerning the efficient processing of the scattering data.

**Index Terms:** Buried inclusion, GPR methodologies, detectability, integral equations, inverse scattering, mixing formulas.

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