Transmission, Reflection, and Scattering Characterization of Building Materials for Indoor THz Communications

The future communication technologies are naturally evolving toward higher carrier frequencies in order to satisfy the demand for increasing data rates. Terahertz (THz) frequencies appear to make high-speed and high data rate communications possible. However, due to the high free-space damping above 100 GHz, communication systems are limited to short range, seldom, non-line-of-sight transmission links, which rely mostly on the reflection properties of walls and other surfaces. We have investigated the scattering coefficients of a representative collection of 50 building materials used for construction. The optical and reflection properties of the samples were measured using THz time-domain spectroscopy and the scattering coefficients were modeled based on the Fresnel-Rayleigh equations and the Kirchhoff theory. The proposed Kirchhoff-Rayleigh approach is appropriate for the scattering characterization of rough surfaces with limitations to resolve the scattering coefficients of materials with a complex structure. Nonetheless, the measured data show the reflection potential of materials commonly found in indoor environments, giving important insight into the further modeling of THz communication channels.