Transmission and reflection properties of interior walls

Reports on measurements made of the transmission and reflection at interior walls made of gypsum board mounted on metal studs, and at walls constructed of concrete blocks in the 2.5 GHz ISM band. Measurements were made using directive horn antennas in order to evaluate the transmission coefficients of the specular components, as well as the scattering into nonspecular directions. In the case of gypsum board walls, the specular components were found to be primarily responsible for carrying the incident energy away from the wall. However, in the case of a concrete block wall, the periodicity associated with the internal webs and voids was found to result strong diffraction into nonspecular components. These measurements are compared to a simplified theory for gypsum board walls that neglects the metal studs, and to a rigorous theory for a periodic concrete block wall