Wideband Terahertz Band Reflection and Diffuse Scattering Measurements for Beyond 5G Indoor Wireless Networks

Measurement results on rough surface scattering on common indoor materials in the terahertz (THz) band from 100 GHz to 4 THz are reported. The measurements were made using THz time domain spectroscopy (THz-TDS)-based measurement device in multiple transmitter and receiver angles for five different materials: aluminium, glass, plastic, hardboard, and concrete. The main interest of this paper is in the frequency domain characteristics of the scattering and reflections on different materials from the viewpoint of possible non-line-of-sight (NLOS) communications in the THz band. The measurements show that the specular reflection component always dominates, even in the case of rather rough concrete sample. The main reason for this is the vast bandwidth: the lower frequencies tend to have strong specular component even if the higher frequencies would diffuse on surface of the material. The results also show that the diffuse scattering field is very weak in comparison to the specular direction. However, it is still theoretically high enough to enable the NLOS links on short distances. The results clearly show that the NLOS paths, especially, reflected paths, can be used for communications in the THz band.