metamaterial masking moves toward practical application

24 02 2011

Via Rachel Courtland, New Scientist. Issue 2800

NOW you see it, now it looks like something else. Radar images might never be the same again, thanks to an illusion device that can change an object’s appearance. The technology could ultimately be used to hide military aircraft.

The device is part of a growing family of metamaterials – structures designed to steer light along curved paths. They have already been used to make objects appear invisible and to disguise a gap between two objects.

Wei Xiang Jiang and Tie Jun Cui’s team at Southeast University in Nanjing, China, have created a structure that changes the way radio waves interact with a copper cylinder so that it appears to be composed of another material altogether.

Copper conducts electricity well and reflects incoming radio waves, giving it a bright radar signature. To alter this behaviour, the team built a device made of 11 concentric rings of circuit boards etched with small metal-lined channels that prevent electromagnetic waves reflecting away. Instead, they guide the waves in a direction that the researchers choose specifically to make the hidden object appear to have different electrical properties.

Placed around a copper cylinder, the arrangement created the illusion that the cylinder was made of a dielectric, a class of materials including porcelain and glass that do not conduct electricity and are more transparent to radio waves.

"Electromagnetic cloak"

A similar waveguide that rendered small objects invisible was tested in 2009.

The illusion only worked when the cylinder was viewed from the side; what’s more, the imaginary object it generated was the same size as the original. Future designs would have to account for all three dimensions, and might produce an illusion quite different from the object they disguise.

“In principle, this technology could be used to make an illusion of an arbitrary shape and size,” says Cui, whose team created an electromagnetic “black hole” for light in 2009. Similar illusion devices could eventually be used for stealth technology: for example, to “convert the radar image of an aircraft into a flying bird”, Cui says.

The work, which will be published in Physical Review E, is still at an early stage, however. At 45 millimetres, the team’s illusion device is three times as wide as the cylinder it disguised. “Their device is still fairly bulky relative to the original object, so further work needs to be done before a real device can be deployed,” says John Pendry of Imperial College London.

Although invisibility devices were invented first, the illusion technology might win the race to be put to practical use. “It is easier to falsify something than to hide it,” Pendry says.

The team next plans to explore ways to design devices with more complex shapes.

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kitty kat cornershot camo

20 06 2009

I thought this was someone’s idea of a joke when I first saw it. But, no – the demonstrator in the video below is deadly earnest (not Deadly Ernest, the comic pro-wrestler from Manchester, UK, but instead, a very, very serious company man ).

Cornershot camo

Cornershot camo

Now, the Israeli Cornershot system is a useful ‘force multiplier’ for dismounted urban operations, but I guess that to those being observed  through its barrel mounted video system it is still obvious that a gun barrel is pointing at them from round the edge of a wall. Until someone came up with this unconventional idea…

Link

Thanks to F Gruenert/ICUS for the tip.





there`s no camo like snow camo…

18 08 2008

OK, I know that some car fanatics and petrol-heads will have seen this already – but for the rest of you, here is what Swedish pro skier Jon Olsson drives around in – a Lamborghini Gallardo in a custom snow camouflage scheme. Clearly inspired by his native country`s splinter style camo uniforms. I think it`s ice cold!

Swedish M90 camouflage pattern

Swedish M90 camouflage pattern

Via Ekhatch and 6speedonline