Everything in our lives, from our refrigerators to our televisions, heating systems, and lights are becoming connected to our smartphones. “Internet of things” technologies allow us to streamline data and expand our capabilities in a number of ways; but as these technologies develop, we will need a greater wireless bandwidth to keep up. Researchers from Brown University recently explored the use of a new frequency range that could one day be used for such devices. Their study is published in the journal APL Photonics.
This new frequency range falls within the terahertz (THz) region of the spectrum, which the researchers think could be used in future wireless communications. As the team explained in a press release, the Brown team is not the first to explore this spectrum, but previous research hasn’t been comprehensive.
The Brown researchers think THz communications not only be useful for ordinary wireless transmissions, but could also create wireless links that rely on indirect, or non-line-of-sight pathways. Researchers previously thought such pathways were impossible.
However, “Our work shows that this isn’t necessarily the case,” said Daniel Mittleman, whose group led the study, in the press release.
The frequencies of THz radiation, reaching over 95 gigahertz (GHz), are so high that the FCC doesn’t even have service rules surrounding them. In fact, this spectrum is so far from what we usually use for wireless carrier waves, like WiFi, that people are worried about how it might affect human health.
Within the study, researchers produced both line-of-sight and non-line-of-sight measurements. For the line-of-sight experiment, they pointed the THz signal directly at a receiver. For the non-line-of-sight experiments, they reflected the signal using objects like a painted cinder block, a door, metal foil, and a smooth metal plate.
In one experiment within the study, the signal and receive were placed where they could not see each other at all. When the signal was sent, it bounced off of a wall (twice) and was then detected by the receiver. This might seem like a minor feat, but it is the first time that non-line-of-sight use has been demonstrated possible within this spectrum, using a THz signal.
These findings go against previous doubts about the use of these frequencies. The potential health concerns surrounding THz radiation will need further exploration, but this proof-of-concept could spark agencies like the FCC to consider future use, build rules surrounding them, and begin further exploration of using this new frequency range practically.
As Ericsson CEO Hans Vestberg told The Mercury News, “You’re going to see this ‘Internet of things’ start demanding network performance and making the networks much more aware of what is on top of them.”