2-D near-field SAR non-destructive testing of rebars in a concrete wall

Abstract

A microwave non-destructive testing technique to localize metal reinforcement bars in a concrete wall is presented. The technique is based on a two-dimensional near-field Synthetic Aperture Radar imaging algorithm in a monostatic stepped frequency arrangement. The resulting, qualitative, images of the induced sources give a clear indication on the position of the highly conductive rebars, thanks to their strongly reflective properties. The algorithm takes into account the presence of the concrete, the complex permittivity of which is assumed to be known. The technique has been succesfully tested on simulated and experimental data for a number of concrete wall samples with various reinforcement configurations.