Tag Archives: Fractal Antenna Systems Inc.

Huge jump forward to invisibility cloaking device

This is pretty remarkable. Usually when researchers talk about invisibility cloaks, they’ve managed to cloak something that is measured at the nanoscale. Here they’ve (Fractal Antenna Systems Inc.) managed to cloak a person within a certain bandwidth,

The Nov. 16, 2012 news item on Azosensors provides more detail,

Fractal Antenna Systems, Inc. today disclosed that it has successfully rendered a man invisible. The firm’s new invisibility cloak hid a subject named Peter at microwaves over a wide bandwidth at high fidelity. This is the first time any large object has been rendered invisible and the first time a person has disappeared from view using invisibility cloak technology.

Invisibility cloaks differ from other types of stealth or camouflage by diverting waves around an object. The opposing side is visible but the object is not. They are unpowered and passively convey that view.

The heart of the invisibility cloak is a close-spaced resonator arrangement made from almost 10,000 fractal shapes. Such shapes are built from simple patterns that are scaled. The human-sized cloak was configured as a large hollow cylinder with the cloak surrounding it as a thin shell. Subject Peter hunkered down inside to become hidden from microwave view, and thus realized a dream of countless generations–the quest to be invisible.

There’s more at Azosensors including an image and a history of invisibility cloaks. You can also visit the Fractal Antenna Systems Inc. website.

The latest invisibility cloak

Fractal Antenna Systems Inc. has released a video which demonstrates an invisibility cloak. From the Dec. 20, 2010 news item on Nanowerk,

The video conclusively shows that invisibility science has taken a huge leap with fractal design. Fractals are geometric patterns that have complex structure built from scaled repetition of a simple pattern. Fractals make up the cloak and its ‘object’ layer, producing a wideband invisibility that slipstreams microwaves around obstacles. The other side appears with good fidelity, without the detectable presence of the obstacle. Although a proof-of-concept of an invisibility cloak was shown in 2006 at Duke University, such non-fractal efforts had limitations. The Duke cloak worked in one narrow band, had many more cloaking layers, possessed a discernable shadow, and required the obstacle to already be hiding behind a mirror. All of those obstacles have been solved using fractals, in grids called fractal metamaterial, as the firm’s cloak reveals.

I located the 2006 video from Duke University,

It’s Fractal Antenna System’s ability to project a wideband invisibility cloak that distinguishes this effort from Duke’s (from the news item),

Notes the firm’s CEO and chief inventor Nathan Cohen: “In 2008, Chinese researchers said it was impossible to make a wideband invisibility cloak. We not only did it, but reduced the number of cloak layers, and, most importantly, made a cloak you can see out of. That means a sensor, for example, can be made to disappear into the background over a wideband, but still be able to see what’s outside. These attributes are really the ‘holy grail’ of cloak designs, and strongly point towards a bright future for invisibility science.”

The fractal cloak works at microwaves; radio waves used by cell phones and wireless devices. The technology directly applies to infrared, and with technology advances in nanotechnology, can be made to make visual light invisibility cloaks, although Cohen cautions that it will be many years before visual light invisibility cloaks are perfected. “Other researchers are still hiding objects behind mirrors. What’s the point of a cloak if you are already hiding behind a mirror?” asked Cohen.

As best as I can tell, the objects that are being cloaked are not visible to the human eye as they are measurable at the nanoscale. Here’s the Fractal Antenna Systems video (from YouTube),

The narrator seems to have some an unfortunate vocal habit, he overmodulates so some parts are a bit ‘sing-song’.