A still from a video the researchers assembled to help explain the inspiration and background for their research. According to the clip, some of their research was done in the same locations as those used by Guglielmo Marconi for some of his ground-breaking radio experiments. |
A
group of Italian and Swedish researchers appears to have solved the
problem of radio congestion by cleverly twisting radio waves into the
shape of fusilli pasta, allowing a potentially infinite number of
channels to be broadcast and received.
Furthermore,
the researchers have demonstrated this in real-life conditions by
beaming two twisted radio waves across the waters of Venice.
Their results have been reported in the March 2 edition of the Institute of Physics and German Physical Society’s New Journal of Physics and are accompanied by a video abstract (link at the bottom of the article) that gives an insight into the authors’ work.
As
the world continues to adapt in the digital age, the introduction of
new mobile smartphones, wireless internet and digital TVs means the
number of radio frequency bands available to broadcast information gets
smaller and smaller.
“You
just have to try sending a text message at midnight on New Year’s Eve
to realize how congested the bands are,” said lead author Dr Fabrizio
Tamburini. The researchers, from the University of Padova, Italy, and
the Angstrom Laboratory, Sweden, devised a solution to this by
manipulating waves so that they can hold more than one channel of
information.
A
wave can twist about its axis a certain number of times in either a
clockwise or anti-clockwise direction, meaning there are several
configurations that it can adopt.
“In
a three-dimensional perspective, this phase twist looks like a
fusillli-pasta-shaped beam. Each of these twisted beams can be
independently generated, propagated and detected even in the very same
frequency band, behaving as independent communication channels,”
Tamburini continued.
To
demonstrate this, the researchers transmitted two twisted radio waves,
in the 2.4 GHz band, over a distance of 442 m from a lighthouse on San
Georgio Island to a satellite dish on a balcony of Palazzo Ducale on the
mainland of Venice, where it was able to pick up the two separate
channels.
“Within
reasonable economic boundaries, one can think about using five orbital
angular momentum states, including untwisted waves. In this instance, we
can have 11 channels in one frequency band.
“It
is possible to use multiplexing, like in digital TV, on each of these
to implement even more channels on the same states, which means one
could obtain 55 channels in the same frequency band,” said Tamburini.
In
addition to increasing the quantity of information being passed around
our planet, this new discovery could also help lend an insight into
objects far out in our galaxy. Black holes, for example, are constantly
rotating and as waves pass them, they are forced to twist in line with
the black hole.
According
to Tamburini, analyzing the incoming waves from the supermassive black
hole at the center of the Milky Way, Sagittarius A, could help
astronomers obtain crucial information about the rotation of this
“million-solar mass monster.”
Encoding many channels on the same frequency through radio vorticity: first experimental test
