A short note onFractal Invisibility CloakBy: Purushottam AbhisheikhEnroll. No.: 15114052IntroductionFrom the earliest days of science fiction, people have been fascinated with the notion of invisibility. Until very recently, that idea remained a fantasy and worthy of profound scepticism but now invisibility is a very real science and Fractal Antenna has already granted Invisibility Cloak Patent. Patent Wideband electromagnetic cloaking systems was issued to Nathan Cohen, founder and CEO of Fractal Antenna Systems. It is a breakthrough based on its widebandedness, fidelity, simplicity of design and ability to see out of when cloaked.An Analogy of a FlashlightIf an opaque object is placed in front of a flashlight then its intensity drops significantly which prevent us from seeing the light. Now if a working visual light cloak, which doesn’t exist yet, is placed on the perimeter of the object, the light would be slipstreamed (Fig. 1) around the opaque object and converge again on the other side giving a feel of invisibility. Fig. 1Nathan’s invisibility cloak does the same thing with microwave radiation.WorkingThe invisibility cloak is a series of partless circuit board rings. Each ring has a myriad of fractal resonators. These resonators, when used in different ways, can have a lens like reflecting or ducting qualities. And with just a handful of such rings, we can get a very wide bandwidth cloak. There is a special inner ring that defines the inside of the cloak. Its conveniently called the object. Anything inside is cloaked as the fractal cloak rings slipstream the microwave around the object.Fig. 2: Fractal Invisibility CloakFig. 3: Fractal pattern used in ringsApplicationThe fractal cloak works at microwaves; radio waves used by cell phones and wireless devices. The technology directly applies to infrared, and with technological 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.