Very Fast Indoor Wireless May Not Need a Clear View Across the Room

A terahertz radio link kept working with a wall in the way, carrying 40 Gbit/s when the signal was bounced off common building materials and 50 Gbit/s when it was sent through them, over a laboratory path 1 meter long. Feng Liu, Alwyn Seeds and colleagues at University College London published the measurements in Communications Engineering on Sept. 16, 2026.

Terahertz frequencies sit well above the bands phones and Wi-Fi use and are expected to carry far more data. The authors write in the paper that links with no clear view between transmitter and receiver will be needed before terahertz radio can be used indoors, and that such links have barely been studied.

The link ran at 146.8 GHz. The group first measured how five ordinary building materials (metal, glass, wood, plasterboard and ceiling tile) reflect a terahertz beam and how much of it passes through, then fitted the results with the Fresnel equations, the standard formulas for a wave meeting a surface. It built two links across a blocked 1-meter bench path: a reflected one that reached a maximum of 40 Gbit/s and one through the material that reached 50 Gbit/s. Both stayed inside the error rate that standard forward error correction can still clean up.

The authors say that, to the best of their knowledge, these are the highest data rates reported for a non-line-of-sight terahertz link using building materials other than metal. They describe the result as showing that fast indoor links around obstacles are feasible and as guidance for designing future terahertz networks.

Part of the receiver hardware came from a European Space Agency technology program and was assembled at the STFC Rutherford Appleton Laboratory near Oxford, according to the paper's acknowledgments.