Researchers from the Ecole Polytechnique Federale de Lausanne and University of Geneva invented a graphene filter that clears the way for terahertz antennas that transmit data up to ten times faster than current technology.
The graphene chip, described in the journal Nature Communications, is also called an optical isolator, which prevent signals and other noise from leaking into antennas. That noise impacts the quality of the transmission, introducing static to a phone call, for instance, or blurring a video stream.
The new device helps compensate for reciprocity, or the natural property of antennas to transmit and receive signals over the same path. When antennas open to let signals out, signals bouncing off walls and other obstacles can get inside the antenna. As antennas become more efficient, they grow more susceptible to this kind of interference.
The researchers found that graphene — an extremely thin lattice of carbon molecules — can be configured to let only certain frequencies inside the antennas. The graphene is either "transparent" or "opaque" depending on the vibration and direction of incoming signals. The researchers compared the new isolator to polarized sunglasses, which eliminate glare by absorbing horizontal light waves, while allowing vertical waves to pass through.
Though isolators are widely used in megahertz and gigahertz antennas inside today's devices, scientists struggle to make isolators and other parts that manipulate ultra-high frequency terahertz waves, which are notoriously difficult to transmit and modulate. The payoff for that technology could be systems that transmit data as fast as 100 gigabits per second.
"Our graphene-based microchip is an essential building block for faster wireless telecommunications in frequency bands that current mobile devices cannot access," said Michele Tamagnone, an Ecole Polytechnique Federale de Lausanne researcher, in a statement.