In-situ characterisation of building materials

The knowledge of the electromagnetic properties of building materials is increasingly important in modern wireless communications due to high indoor communications demands. This paper describes a free-space measurement technique based on the ground penetrating radar (GPR) principle to characterise building materials. The constitutive parameters of the material under test such as the number of layers, the thickness and dielectric constant of each layer can therefore be determined. An inverse scattering algorithm for reconstructing these parameters, which is based on the global minimisation of the defined objective function using the multilevel single-linkage method, is developed and applied to this application. Results of measurements on standard sample materials and some building materials are presented and discussed