Advanced Three-Dimensional Microwave Tomography for the Imaging of Buried Targets

The imaging of buried targets by means of Ground Penetrating Radar (GPR) surveys is typically affected by nonideal and critical operational conditions. The targets are often located in the near-field region of the illuminating antennas, having size comparable to the probing wavelengths and, thus, to the resolution limits of the considered system. In this work, we investigate the improvements obtainable in the GPR performance when the post-processing of the signals collected at the receiving system accounts for the actual near-field distribution of a directional antenna used to activate the scattering phenomenon. In contrast with more conventional implementations., which are based on a two-dimensional (2-D) scalar representation of the scattering equation., we consider here a three-dimensional (3-D) vector formulation of the scattering problem, modeling the illuminating field with the actual 3-D near-field distribution impressed by the considered antennas. Preliminary 3-D numerical reconstructions of the target are reported and discussed, paving the way for a complete performance assessment of a fully vector near-field microwave imaging with respect to the usual simplified implementations.