Extraction of dielectric properties of building materials from free-space time-domain measurement

Both the reflectivity and transmissibility of the building materials are dominant factors to the propagation of radio signal within indoor environments. As these parameters are strongly related to the dielectric properties of building materials, they can be obtained only when the building materials are well characterised. This paper describes an approach to extract the dielectric properties of building materials by using a free-space time-domain monostatic measurement system. Taking multiple reflections inside the testing material into account, a plane-wave reflection coefficient algorithm is implemented to extract both the complex permittivity and thickness of the testing material by optimising the measured reflection data. Both reflection coefficient from the material and transmission coefficient through the material can therefore be obtained from theoretical formulation