Assessment of Cavities and Water Contents Through the Complex Dielectric Permittivity Computed By the Boundary Integral Equation Method

This paper presents a method for characterising the of heterostructures consisting of discrete inhomogeneities embedded in a three‐dimensional homogeneous matrix. This method is based on the measurement of the effective complex permittivity. It enables to characterise different media and to determine the presence of inclusions and their concentration in a given heterostructure. To illustrate this technique, measurements are carried out in samples composed of identical aligned inclusions, in the form of circular cylinders, embedded in a polymer matrix and which are filled either by water or air. The experimental results are compared with the results predicted by a numerical approach based on the boundary integral equation method (BIEM) and the PHI3D package. The numerical simulations are found to capture reasonably well the observed trend in the experimental data over a wide range of volume fraction of inclusions.