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There are a couple of videos on the Fractal Antennas website Fractal Antenna: Whats New. Looks like they have something for microwaves. But when they start talking about how this could be scaled up from microwaves to visible light I start to get a bit skeptical.

The first fractal antennas were invented in the 1950's, long before Mandelbrot turned self-similarity into fractional dimensionality. The particular antenna I'm talking about is the log-periodic.

Also, Nokia didn't invent the concept of fractal antennas; Nathan Cohen did, in 1988.

fyngyrz, posting anon consequent to slashdot's cowardly mechanism for moderators.

You probably caught the Nova Episode about fractals, it has a segment where it talks about fractal phone antennas:

http://www.hulu.com/watch/181084/nova-hunting-the-hidden-dimension

Here's some other stuff:

http://en.wikipedia.org/wiki/Fractal_antenna

http://classes.yale.edu/fractals/Panorama/ManuFractals/FractalAntennas/FractalAntennas.html

http://www.fractenna.com/

Why bother fractal antennas can broadcast and recive on multipule wavelengthsin one antenna right now. All the benfits of a whip and a phased array in one device.

http://www.fractenna.com/

"One thing I learned is that knowledge of fractals is almost useless. Fractal compression doesn't compete very well with Wavelet compression (used now), and there's virtually no other area to which they have been applied successfully."

Spoken like a true Slashdotter.

http://www.fractenna.com/

"The other side of this is that some people who understand how to make antennas had to figure out a compact array of antennas which would not need any sort of calibration and which would provide the necessary hardware to even use this software signal processing technique. Those are the people that really impress me, because I am horrible with mathematics."

Fractal Antennas. Anyway, thanks, but when it comes down to it. It's all math. It's just the realm it eventually ends up living in.

Set the kind of post to "HTML Formatted", using the little menu in the lower right. Then wrap HTML markup around it:

<a href="http://www.foo.com/"> Text that you want highlighted </a>

Fractenna is actually a pretty interesting-looking link. Thanks.

This is all fine and dandy--
but when are we going to be able to buy the fractal antennas we heard about a few years ago. They were supposed to be the bomb, and I wanted one for TV, but they don't seem to sell any consumer models. What up with that?

Well, nice, but is it better than fractal antennas, i.e. Sierpinski antennas?

OK, there is more to RF spectrum than just 802.11b (well, lets call it microwave to encompass all the frequency ranges that have issues with water absorption and going through walls ofr any great distance)

an alternate approach might be tick a different part of the spectrum or wait for UWB devices to become available...

however, another way might be to stencil a wireless antennae onto a window. for example fractal antennaes are available with a very small foot print. The idea would be to stencil an appropriate antenna shape onto a window with conductive media (seveal conductive paints are available) or to buy a fractal antenna of the guys linked above (after all, you wouldn't want to infringe their patent would you?)

Amusingly, Slashdot rejected an article submission I had for fractal antennas and how they are vastly superior in terms of reception to whats on the market today. Better than the stuff mentioned in this article, certianly.

Cheers, and yes PROPAGANDA will be back soon.

Phil Reed sez:

Better take another look at patent law. If the guy has a patent on antennas, then he can restrict the manufacture of the antennas under all circumstances, including cooking one up at home. Doesn't necessarily mean he'll come after you if you do just one for yourself, but he's legally allowed to. No such thing as 'fair use' of a patent.

There's been a fair amount of discussion on the fractal antenna on various ham radio mailinglists, and whilst the antenna IS patented the person who owns the patent has explicitly given permission for the antenna to be used in non-commercial applications below cellular band.

On the Fractenna Homepage there are also explicit instructions on how to build a fractal antenna for various ham radio bands.

Warning: Subjects of a technical nature relating to both fractals and radio bandwidths follow. It shall be assumed that you have at least some grounders in both fractals and in antenna design if you are reading past this point. If you don't know what the hell a Koch curve, common ham radio terms, wavelength, or Yagi antennas are then the following will probably be of no use whatsoever. :)

As far as I can tell, apparently the fellow has made the antenna in the rough outline of a fractal resembling a Koch curve with squares and pointing inward instead of outward and with triangles (as in normal Koch curves). I don't know of too many hams using them just yet, but once programs are written where one can custom-design such an antenna by both wavelength and iterations then I'd expect more folks to be using them. There's been a fair amount of excitement in the QRP community at least, because one can pack a lot of antenna in one space and antennas for 20 meters and below that don't require longwire hookups, Slinkys, or towers become practical.

The designs for use in ham radio seem to be variations of Yagi square antennas (fairly common for homebrew use) where instead of a square one uses the "modified inverse Koch square" (for want of a better term for the fractal used) for the upper and lower ends of the band. These are better suited for directional antennas, of course (as are all Yagis); if one didn't want to use it as a Yagi and wanted a non-directional antenna I see no real reason you couldn't use a fractal antenna as a sort of modified loop antenna. (Folks doing AM DX listening in cramped quarters where installation of a longwire antenna is impossible ought to like that. ;)

If memory serves, calculating wavelengths for the "Yagi fractenna" is a bit more of a bear than configuring wavelengths for the normal type of Yagi. Again, though, it should be possible to figure out a way to rig up a quickie program to determine wavelength.

Just like the man said, the Fractenna is not going to give you ANY more gain than a Yagi antenna of comparable wavelength. What it does do is allow one to install a rather large (in wavelength and in wire length) antenna in a much smaller space than one would normally do so.

(end technical discussion)

Now, as for other interesting uses of fractals...I have heard of a number of kite enthusiasts who have built working kites based off of Sierpinski sponges. (Sierpinski sponges are just like Sierpinski gaskets or triangles, but in three dimensions. ;) Apparently the things get amazing lift--one has to be careful not to let the kite drag you because you're dealing really with upwards of four or more box kites! :)

A quickie search of Alta Vista for "fractal kite" or +kite +Sierpinski should lead you to some articles on how to make them and fly them. ;)