Non-line-of-sight terahertz communications enabled by reflection and transmission

Terahertz communication is expected to be a key technology for future wireless networks, offering ultra-high capacity, beyond the limits of conventional radio-frequency systems. To enable practical implementation, investigating non-line-of-sight terahertz links is essential, but this remains largely unexplored. This paper presents an experimental demonstration of a non-line-of-sight terahertz link at 146.8 GHz using common building materials. The reflection and transmission properties of metal, glass, wood, plasterboard, and ceiling tile are characterised and fitted using Fresnel equations. Based on these measurements, reflection- and transmission-based links over a 1 m non-line-of-sight path are established, achieving maximum data rates of 40 Gbit/s and 50 Gbit/s, respectively, while satisfying the soft-decision forward error correction threshold. To the best of our knowledge, these results represent the highest reported data rates for non-line-of-sight terahertz links using building materials other than metal, showing the feasibility of high-speed indoor non-line-of-sight terahertz communications and providing guidance for future terahertz network implementation.