Terahertz Wireless Communications: Research Issues and Challenges for Active and Passive Systems in Space and on the Ground above 100 GHz

This paper demonstrates how spectrum up to 1 THz will support mobile communications beyond 5G in the coming decades. Results of rooftop surrogate satellite/tower base station measurements at 140 GHz show the natural isolation between terrestrial networks and surrogate satellite systems, as well as between terrestrial mobile users and co-channel fixed backhaul links. These first-of-their-kind measurements and accompanying analysis show that by keeping the energy radiated by terrestrial emitters on the horizon (e.g., elevation angles $\leq$ 15\textdegree), there will not likely be interference in the same or adjacent bands between passive satellite sensors and terrestrial terminals, or between mobile links and terrestrial backhaul links at frequencies above 100 GHz.