New metamaterial with unusual reflective property could boost your Wi-Fi signal
Date:
September 30, 2021
Source:
University of Toronto Faculty of Applied Science & Engineering
Summary:
Engineers have achieved a practical mechanism for 'full-duplex
nonreciprocity,' a property in metamaterials that allows for
manipulation of both incoming and reflective beams of light.
FULL STORY ==========================================================================
Your office wall might play a part in the next generation of wireless communications.
========================================================================== University of Toronto Engineering researchers Professor George
Eleftheriades and postdoctoral fellow Sajjad Taravati have shown how
reflectors made of metamaterials can channel light to enable more wireless
data to be transmitted over a single frequency.
They project that this newly realized property -- called 'full-duplex nonreciprocity' -- could double the capacity of existing networks. The intellectual property (IP) for the team's proof of concept has recently
been transferred to the Montreal-based startup LATYS Intelligence Inc., cofounded by Engineering alumnus Gursimran Singh Sethi.
"This is happening," says Eleftheriades. "Within the next three to five
years this technology will be adopted." Metamaterials are synthetic
structures composed of building blocks that are smaller than the
wavelengths of light they are designed to manipulate.
The material used by the team is composed of repeating unit cells about
20 millimetres in size. This means that to wavelengths of light larger
than that, such as microwaves -- the type of light used to carry cell
phone signals and with wavelengths in the range of several centimetres --
they appear to form one homogenous object, a metasurface.
========================================================================== Microwaves reflect off the metasurface, but they do so in an unusual way, exhibiting a property known as nonreciprocity.
"When you're driving and look in the rear-view mirror, you see the driver behind you. That driver can also see you because light bounces off the
mirror and follows the same path backwards," says Eleftheriades.
"What's unusual about nonreciprocity is that the incident angle and the reflected angle are not equal. To be specific, the backward path for
the wave is different. Basically, you can see someone, but you cannot be
seen." In addition to this functionality, these metamaterials enable you
to steer and amplify incoming beams, which is useful in many applications,
from medical imaging and solar panels to satellite communications and
even nascent cloaking technology. With an added capability to steer the reflective beam, new intelligent metasurfaces could make a significant
mark on wireless communication.
"In everyday experience," says Eleftheriades, "a microwave emitted from
a tower reaches its intended terminal point, like a modem, and then
goes back to the telecommunication station. That's why, when you have
a conversation on your cellphone, you do not talk and listen on the
same channel. If you did, the signals would interfere and you wouldn't
be able to separate your own voice from the voice of your partner."
Today's 5G features only 'half-duplex' links. Essentially, the 5G
signal uses slightly different frequencies, or the same frequency but
at a slightly different time, to avoid interference. The time delay is imperceptible to the user.
==========================================================================
The full-duplex architecture developed by Eleftheriades and Taravati
means that one can talk and listen on the same channel at the same
time. Unlike other metamaterial technology, it spatially separates the
forward and backward paths within the one frequency -- doubling the system capacity. Their research is presented in a paper in Nature Communications.
While full-duplex functionality does exist in a limited capacity in
military- grade radars, in its current design it is unsuitable for
consumer applications, such as mobile devices. This is because current full-duplex transceivers are made of bulky and expensive structures
comprising ferrite materials and biasing magnets to manipulate the beam.
"We propose a completely different mechanism. No magnets or ferrites.
Everything is done using printed circuit boards and silicon electronic components such as transistors," says Elefthreriades.
The broad applicability of these intelligent metasurfaces is what excited LATYS's development team.
"Tunable, asymmetric radiation beams in both the reception and
transmission states have incredible potential to address some of the
most pressing and major challenges in the wireless communication
industry," says Sethi. "By spatially decoupling the receive and
transmit paths, we can create 'true full-duplex systems' that
can support bidirectional communication at the same time and the
same frequency. This will allow LATYS products and prototypes to
gain an edge over competition and much traction, especially in
radio-hostile environments such as industrial automation, IIOT and
5G applications." "Just imagine," says Eleftheriades, "as we're
integrating some of these surfaces in the walls of buildings,
researchers are hard at work on the next iteration of 'better.'" ========================================================================== Story Source: Materials provided by University_of_Toronto_Faculty_of_Applied_Science_& Engineering. Original written by Matthew Tierney. Note: Content may be edited for style
and length.
========================================================================== Journal Reference:
1. Sajjad Taravati, George V. Eleftheriades. Full-duplex reflective
beamsteering metasurface featuring magnetless nonreciprocal
amplification. Nature Communications, 2021; 12 (1) DOI:
10.1038/s41467- 021-24749-7 ==========================================================================
Link to news story:
https://www.sciencedaily.com/releases/2021/09/210930160444.htm
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