ETH Zurich researchers transmitted a net 138.6 gigabits per second wirelessly from Uetliberg to the ETH campus, a distance of 5.5 kilometres. Operating at 273 GHz, the link crossed urban terrain, waterways and forest. A resonant plasmonic modulator converted the weak incoming radio signal into light, while improvements to the optical receiver doubled its sensitivity.
The result demonstrates fibre-like capacity over a city-scale wireless connection, potentially useful where installing cable is difficult or for temporary backup links. Measurements covered about six and a half hours on one July afternoon and evening. Reliability across seasons and in rain remains to be tested.
