Homepage - RF Cafe
Webmaster: Kirt Blattenberger | KB3UON | Sitemap | ©1996-2014     Visit RF Cafe on
      Menu below is just a small sample of what is here!          Visit RF Cafe on Facebook Visit RF Cafe on Twitter Visit RF Cafe on LinkedIn
Custom Search
More than 10,000 searchable pages indexed.
•−•  ••−•    −•−•  •−  ••−•  •
RF Cafe Morse Code >Hear It<

Fractal Cloaking Antennas

RF Cafe Smorgasbord - Fractal Cloaking AntennasFractals have been a mathematical curiosity since first being popularized by Benoit Mandelbrot (who coined the term) in the 1960s. Perhaps, and in retrospect no coincidence, was the popularity of the cloaking concept featured in the 1960s phenomenon called Star Trek. I say coincidence because who would have guessed that some of the leading research in invisibility cloaking would involve barriers derived from fractal forms? Have aliens been guiding the technology? If so, maybe they're working at Fractal Antenna Systems, because in mid December the company issued a press release detailing work being done on a cloaking system that works in the microwave band (as opposed to visible light) - chosen for convenience of size. Results are quite impressive as can be seen in the videos.

I am not totally convinced that fractals are a necessary part of cloaking, but they do make for interesting publicity photos. After all, if fractals are part of the cloaking equation, then wouldn't fractal-shapes in nature like coastlines and foliage help make them invisible to something noticeable - sound, light, and/or water waves? The magic is probably in the increased projected surface area generated by a fractal's stepped outline. A multitude of similarly dimensioned curved surfaces might actually be better, but curves are broken down into polygons for computer modeling, so that still leaves you analyzing multifaceted flat surfaces. 

 


Fractal Metamaterial Antenna Monopole Demonstration


 


Fractal Metamaterial Wideband Invisibility Cloak

Fractal Antenna Systems Press Release - December 21, 2010



(Waltham, MA--21 Dec 2010) Can you see it? Researchers at Fractal Antenna Systems have written a new chapter in the science of making things disappears. Their wideband microwave invisibility cloak, first revealed in March 2009, now makes its debut for everyone to see in a new video: http://fractenna.com/whats/whats.html
 
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.

Holy Grail of Cloak Design
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.

The firm's cloak also marks the steady and remarkable process of innovation afforded by fractals in antennas and electronics. Oddly, many American antenna researchers have shied away from fractal design, while interest in Asia and Europe bloomed, noted Cohen. However, as recently shown on PBS's NOVA television program, fractals have a great impact on antennas and electronics, and researchers from all continents except Antarctica now boast many dozens of active research programs.

Cohen also believes that success in cloaking science requires a body of diverse knowledge, which in his case drew upon experience as an astronomer, and curiously, as a radio ham operator. "I have a Ph.D. in astrophysics and am a retired college professor. But the experience I gained as a young ham radio operator was invaluable in helping me make knowledge connections to make the cloak work. That's, in part, why my research group did this first, and why we continue to lead in innovation in fractal electronics, both in basic research and application to products."

Fractal Antenna Systems, Inc.
Fractal Antenna Systems, Inc. (http://www.fractenna.com) 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 15 years in business. The company is a privately held and headquartered in Waltham, Massachusetts, USA.
SOURCE: Fractal Antenna Systems,Inc.
 
CONTACT: Jane Winter JWinter@fractenna.com



Posted 12/30/2010


These items are an archive of past Topical Smorgasbord items that have appeared on the RF Cafe homepage. In keeping with the "cafe" genre, these tidbits of information are truly a smorgasbord of topics. They all pertain to topics that are related to the general engineering and science theme of RF Cafe.

| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 |
| 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 |
| 29 | 30 | 31 | 32 | 33 | 34 | 35 |

Please send me an e-mail if you have a good subject.
A Disruptive Web Presence

Custom Search
Over 10,000 pages indexed! (none duped or pirated)

Read About RF Cafe
Webmaster: Kirt Blattenberger
    KB3UON

RF Cafe Software

RF Cascade Workbook
RF Cascade Workbook is a very extensive system cascaded component Excel workbook that includes the standard Gain, NF, IP2, IP3, Psat calculations, input & output VSWR, noise BW, min/max tolerance, DC power cauculations, graphing of all RF parameters, and has a graphical block diagram tool. An extensive User's Guide is also included. - Only $35.
RF system analysis including
frequency conversion & filters

RF & EE Symbols Word
RF Stencils for Visio

Product & Service Directory
Personally Selected Manufacturers
RF Cafe T-Shirts & Mugs

RF Cafe Software

Calculator Workbook
RF Workbench
Smith Chart™ for Visio
Smith Chart™ for Excel
Your RF Cafe Progenitor & Webmaster
Click here to read about RF CafeKirt Blattenberger... single-handedly redefining what an
                                 engineering website should be.

View the YouTube RF Cafe Intro Video Carpe Diem! (Seize the Day!)

5CCG (5th MOB): My USAF radar shop

Airplanes and Rockets: My personal hobby website

Equine Kingdom: My daughter Sally's horse riding website