Study of feasibility of building materials electromagnetic characterization

Abstract

The objective of this study is to verify the possibility of realizing transient electromagnetic modelling for buildings with numeric equivalent material. This material would allow getting similar results to a real material according to criteria as transient peak level, rise time, and half time duration. The study is limited to signals of frequencies below 1 GHz. Equivalent materials used are homogeneous with scalar characteristics (εr, σ), which are deduced from experiments led on real materials. The advantage of using these equivalent materials for modelling is to coarser mesh large cases in order to save computational resources. The first experimental part of the study is realized using the NADIA open strip-line, which is made of a horizontal metallic ground plane and the strip-line, terminated with resistors. A cinder blocks wall is built according to dimensions of NADIA window, and the strip-line is set up in front of the wall. With multiple electric field sensors, the attenuation brought by the cinder blocks wall is measured, but also the propagation time of the wave through the cinder blocks. The second part is focused on the modelling aspect. It permits to show if a simple homogeneous equivalent wall is able to model a numeric cinder blocks wall. It is also necessary to take care about the fact that the material is dispersive, and it is a matter to know if a simple couple (εr, σ) is sufficient to describe the material. Eventually, a simple method of building material characterization will be highlighted.