Belmont, Massachusetts native Nathan “Chip” Cohen, the founder of Fractal Antenna Systems Inc. and inventor of the fractal antenna, has been granted a patent for deflective electromagnetic shielding. In simpler terms, the patent is essentially for a “cloaking” technology to defend against detection by radar and similar technologies. The patent covers electromagnetic cloaking and deflection of satellites, rockets, towers, antennas, vehicles, body coverings, ships, spacecrafts, and even other people (just to mention a few).
“Much time and effort has been devoted to the quest for so-called invisibility machines,” according to the patent’s background information. “Beyond science fiction, however, there has been little, if any, real progress toward this goal.”
According to the detailed description, the technology provides one or more surfaces that act or function as shielding and/or cloaking surfaces where at least a portion of the surface includes (or is composed of) “fractal cell,” which are small fractal shapes functioning as antennas or resonators, placed sufficiently close to one another so that current present in one cell can be replicated or reproduced to an extent and in an adjacent fractal cell. Without limits imposed by any theoretical explanation, surface plasmonic waves allegedly cause this kind of replication in conjunction with evanescent waves, so the resulting surface would deflect around an object.
Regarding backscatter, which radar systems depend upon, Cohen explained the process as bluntly as possible.
“The incoming wave reflects off a boundary condition at the object. Its reflection is out of phase and phase-cancels with the incoming wave. Bye-bye, backscatter.”
Personal invisibility was initially demonstrated by Fractal Antenna Systems back in 2012 for a Radio Club or America audience, while “invisibility cloaks” had been demonstrated at the Hemvention and ARRL New England Division Convention. Uses of newly patented technology extend to commercial needs like towers, antennas, people, and shielding, but could also be used in defense and intelligence arenas.
The technology produces these desired effects without any significant requirements regarding special orientation, composition, or shape of the object. While the cloak or deflector can be very thin, the effect can happen over a wide bandwidth. The company did mention how “cloaking” applications concentrate on microwave and infrared wavelengths, although the technology and patents also apply to visible light.
“Cloaking at visible light has limited needs. Camouflage and projection methods are easier and cheaper at making something disappear to the eye,” says Cohen. “But at radio and heat wavelengths, the cloaking technology is an important enabler.”
