Breakthrough demonstrations of invisibility cloaks , including a wearable invisibility cloak/ deflector shield, were presented at the Radio Club of America Technical Symposium in New York City on November 16. Previously a science fiction premise, Invisibility cloaks are passive devices that divert electromagnetic waves around an object, rendering it invisible.
Accomplishing this successfully has been pioneered, using radio microwaves, by Fractal Antenna Systems of Waltham MA. The firm uses its proprietary fractal based technology to make fractal metamaterial for a unique advantage in invisibility cloaks , antennas, and other electronic devices.
Starting with a symposium presentation of wideband , thin, and shadow-less invisibility cloaks, Nathan Cohen, inventor and physicist, and CEO of Fractal Antenna Systems, proceeded with a video of the world’s first cloaking of a man.
But more was to come.
The team from Fractal Antenna Systems then conducted a live demonstration of cloaking, making metal pipes disappear over a large microwave bandwidth, with no sensitivity to angular orientation (omnidirectionality).
“Now let’s make a bigger sort of pipe vanish”, said Cohen, as one of Fractal’s engineers attached a thin invisibility vest/deflection shield to his chest.
Before a packed room of engineers and wireless aficionados, this thin conformal invisibility cloak made the engineer’s chest disappear from radio view over a 10% bandwidth in frequency, restoring the radio link as if nothing was there. Without the cloak, the engineer blocked the radio waves with up to 20 dB of attenuation. Adds Cohen, ”We turned him from being a door into a window--at microwaves. Radio waves were passed around to the opposite side. It’s an invisibility cloak and it’s a deflector shield in one.”
Cohen, the inventor of the invisibility cloak (patent 8,253,639) has been leading his team on active construction of invisibility cloaks for nearly 5 years. “We built the world’s first invisibility cloak in 2008 and 2009, from my invention. Others’ earlier efforts did not so qualify as inventions capable of enablement and utility, according to the U.S. patent office. By 2012, the tremendous public interest coincided nicely with the patent issuance. I was honored to be able to present this invisibility cloak technology to the Radio Club of America, the country’s oldest organization of wireless and radio.”
The impending release of the world’s first invisibility cloak patent 8,253,639 set Cohen’s team to cloak a man at microwaves, which they accomplished first on 13 August 2012. An example is shown in video:
CLOAKING A MAN--NOW A REALITY!
No one else has demonstrated the ability to cloak a man or any large object.
An alternative ‘perfect ‘cloak approach taken by other researchers, when scaled, would be a gigantic metal doorframe surrounding a huge diamond-shaped cover, and a person inside a capsule. Such ‘perfect cloaks’ work at only one frequency and only one direction. Turning an inch would stop the cloaking. Meanwhile the huge ‘perfect’ cloak structure makes it much easier to see at adjacent frequencies, improving visibility rather than preventing it. "From the desire for a super-restricted result at just one frequency and one position , the ‘perfect’ cloak approach would turn people instead into super-visible barn doors. If you cloaked a missile this way the enemy would shift frequency a smidgen and its appearance would be screechingly bright.” notes Cohen. "The ‘perfect cloak’ is not a perfected cloak. We don’t make ‘perfect’ cloaks”
Queried Cohen, “I challenge my colleagues to cloak a person. We’ve reached that benchmark. How about you?”
Cohen notes that even the existing human cloak , being a large cylinder, brings up the desire for a wearable version. ”So we made the invisibility vest/deflector shield.” The wearable invisibility cloak, as a vest, addresses the key issues with cloak technology: can you cloak something big; can you cloak it in high fidelity; can you make it thin so it is wearable; and can you make it flexible. “The answer is clearly ‘yes’, states Cohen.” This isn’t the future. We have it now.”
“ Seeing is believing.”
About Fractal Antenna Systems
Fractal Antenna Systems, Inc. supplies products for the world's most demanding wireless, and electromagnetic applications. Backed by over three dozen U.S., and international patents, plus dozens of patents pending, Fractal Antenna Systems is the recognized pioneer in fractal technology, with extensive research and field experience over 18 years in business. The company is a privately held and headquartered in Waltham, Massachusetts, USA.