Researchers develop new cloaking technology
There are a lot of reasons to want to make things invisible, other
than it just being incredibly cool. There are the many potential
military uses of cloaking technology, of course, but it could also help
improve cellular signals by hiding objects that would normally block and
weaken signal strength.
Cloaking technology is
popular science fiction trope, but real scientists have been researching
and developing new ways to make cloaking objects a reality for years.
Most recently, two researchers at the University of Toronto have found a
new way to cloak an object using tiny antennas.
In a paper published this week
in the journal Physical Review X, they describe their new take on
cloaking. They're not making objects invisible to the human eye but
making them undetectable by radar. They can even control the signals
bouncing back to make objects seem larger or smaller than they really
are.
Radar works by sending
out electromagnetic waves that reflect off objects and bounce back to
the detector. In the past, researchers have made things invisible to
radar by redirecting the waves around the object. University of Toronto
researchers Dr. George Eleftheriades and Michael Selvanayagam took a
different approach more suited to large objects.
The nanoantennas they
used radiate an electromagnetic field that prevents waves from
reflecting back to the radar detector. The small antennas can be even
printed flat to create a flexible skin for the desired object. While the
technology only works for radio waves at the moment, the researchers
say the same principals could be applied to other waves such as light
waves, which could potentially hide an object from the human eye.
In their demonstration,
Eleftheriades and Selvanayagam tested the antennas on an aluminum
cylinder. Currently, the antennas need to be manually set to the proper
frequency they're blocking, but in a more advanced set up, they could
detect the different waves and adjust accordingly.
There have been numerous other attempts to make things disappear.
In March, researchers at the University of Texas in Austin
created a material that could be used to cancel out the microwaves
bouncing off an object. Researchers at Michigan Technological University
have experimented with cloaking objects from microwave and infrared
frequency waves using shells of nonconductive materials such as ceramics
and glass metamaterial to distort waves.
A professor in Japan
used cameras to film a scene and then project it on an object in front
of that area onto a special reflective material, creating a visual
camouflage.
It's going to a long
while before we're picking up our own personal cloaking devices at the
local Best Buy. But new research in this field is constantly tacking
new, wider bandwidths and experimenting with less cumbersome technology
that can be used on larger devices.
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