Measured Reflection and Transmission Properties of Building Materials for Indoor THz Communication

The knowledge of reflection and transmission properties of building materials is crucial for understanding radio propagation and developing efficient channel models in terahertz (THz) indoor wireless communication. In this letter, such fundamental interaction mechanisms for five common building materials at 219-224 GHz are extensively investigated through experimental measurement campaign, including glass, granite, polyvinyl chloride board, ceramic, and wooden board. Measured results indicate that the reflection coefficients gradually decrease with the increasing of incident angle, whereas the transmission coefficients show weaker angle dependence. In particular, we compare the measured results with those at 40-50 GHz and investigate different characteristics of the materials at the two frequency ranges. Furthermore, the complex permittivity is extracted using least squares fitting methods based on measured reflection coefficients. The results presented in this letter can offer guidance to channel modeling at 220 GHz for indoor low-THz communication.