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Posted: March 26, 2009
Big Obstacle Disappears with Metamaterial Breakthrough
(Nanowerk News) Fractal Antenna Systems, Inc., an antenna and electronics firm, today demonstrated the first wideband, high fidelity performance from metamaterials. Metamaterials are man-made structures that are built from patterns of electronic resonators. The behavior of metamaterials can be used to make light bend in the 'wrong' direction; enabling unusual lenses and invisibility cloaks.
The firm solved a key problem limiting the practicality of metamaterials--how to make them work at a large range of wavelengths. Previous efforts by others had not succeeded, and had only shown practical use at narrow bands, or single colours.
At its Open House today, the firm showed the world's first wideband see-through 'invisibility cloak'. The invisibility cloak causes microwaves to bend around an object to the other side and have close to same intensity, as if there was no object at all. Noted Fractal's CEO Nathan Cohen: "Previous researchers had measured this 'through to the other side' cloaking at a narrow microwave frequency band. Ours is better than ten times wider. By analogy, if this was visible light, the entire spectrum of visible light would easily pass through, not just one color. To our eyes, the cloaked object would not exist."
Wideband behavior has been the main obstacle to making metamaterials, of which cloaks are just one application, truly practical. Cohen believes that many metamaterial applications are now rendered practical from a scientific standpoint, and the remaining challenges are predominantly those of manufacturability, cost, and identifying useful applications.
Cohen adds: "We will be using our proprietary wideband metamaterial technology to have some fun with cloaking, but don't expect to cloak Harry Potter soon. We've shown that's its physically possible and wideband metamaterials are reduced to practice. But we'll pay somewhat more attention to real needs of the marketplace in other applications at microwave, IR, and visible light."
Fractal has previously filed for patent protection on its wideband metamaterial technology, and is the patent holder on fractal resonators, used in making the metamaterial invisibility cloak. It disclosed the scientific approach to wideband metamaterials earlier in the year at the NANOMETA 2009 conference. The firm will be placing the results and description of the invisibility cloak on its websites shortly.