Think your network is fast? Getting a gigabyte-sized movie over your local wireless network to your hard drive in a few seconds is old hat. Now there’s a network that can push a 2-hour, high-definition movie to a computer a mile away in less time than it takes to read a single word.
At the Karlsruhe Institute of Technology in Germany, a new record has been set: 40GB per second over a distance of about .6 of a mile. That’s like sending 10 high-def feature films.
What makes this possible is a combination of better hardware and the use of higher radio frequencies, in this case, 240 gigahertz.That hardware is a set of chips developed at Karlsruhe that can process signals at higher frequencies. Higher frequencies mean smaller components, since a shorter wavelength can be picked up by a smaller antenna (which is why FM and AM radios need relatively large antennas, while Wi-Fi receivers can use small ones). These chips were only a few millimeters on a side.
The high frequencies are necessary for moving lots of data — the number of bits that can travel over the airwaves is inversely proportional to the wavelength. The shorter the wavelength, the more data that can go in a given time.
A Wi-Fi network operates at 2.4 or 5 GHz, and tens of megabytes per second is not uncommon. Smartphones on the latest networks work at frequencies somewhat below that, and it’s no accident that they struggle to hit 10MB per second.
At some high frequencies moisture in the air can cause the signal to fade, but 240 GHz seems to be in a sweet spot where there’s little interference from moisture. Since transmissions can go much further than a Wi-Fi router can manage, there’s a possibility this type of transmitter would work well for rural areas where laying down fiber-optic cable — the gold standard of transmission speed — is too expensive to justify.
Image: The high frequency chip developed by the Karlsruhe Institute of Technology. Credit: Karlsruhe Institute of Technology/Sandra Iselin/Fraunhofer IAF