[TowerTalk] Fractal Antenna's

jimlux jimlux at earthlink.net
Sat Feb 20 15:08:37 PST 2010

Neal Campbell wrote:
> The greatest story on this is from a show on PBS about Fractal Geometry.The
> first half of the show is about how skeptical and belittling the mathmatical
> world was about fractal geometry when it could be proven over and over and
> seen recurring everywhere in nature.
> The second half of the show was about the practical applications of fractals
> and they spent quite a bit of time telling the story of Nathan Cohen who as
> a ham started to wonder if antennas would benefit from fractal design and
> wrote a paper in Communications Quarterly. He kept going, finally starting
> up the Fractal Antenna company which sells antennas it seems in the cell
> phone market, etc.

More correctly, he sells licenses to use the patent, and hopes to get 
investors. They probably do make some antennas.

As others have pointed out, there's an infinity of ways to make a 
physically small antenna, if you're willing to give up gain or 
bandwidth.  Fractals are but one, and lend themselves to sexy marketing 

Note also that just because the Dept of Defense or NASA buy something 
doesn't mean that it actually is any better than anything else.  For all 
you know, they bought it for test purposes.

There are also rumors that the inventor is fairly assertive, and doesn't 
take kindly to folks wanting to do "head to head" comparisons.  It's 
kind of hard to legally build an example of a fractal antenna to test on 
an antenna range against, say, a meander line or loaded dipole without 
violating his patent.  I don't know, but he could easily put a 
restriction on purchasers of his antennas that you not publish test 
results from antenna range measurements.

This is like various software companies that have, as a part of the 
license terms, that you cannot publish benchmark results from their 

The common law exception (viz Whittemore vs Cutter, 1813) in patent law 
for "experimental duplication" of the patented article has some 
limitations.  You can duplicate to perform scientific experiments or to 
  test the patent's claimed utility.  Later, the same judge (Justice 
Story) explained more in other cases, basically saying if it's for 
profit, it's clearly not in either of the two cases, and because 
businesses exist to make a profit, no business can claim the exemptions.

Later cases narrowed the exemption further: "for the sole purpose of 
gratifying a philosophical taste, or curiosity, or for mere
amusement" but not for "experiments with a view to the adaptation of the 
invention for the experimenter's business, or for the convenience of the 
experimenter (say you used the patented device to make your other job 

Most interestingly, in Bonsack Machine Company v Underwood in the 1890s, 
it was held that using a patented machine for the purpose of comparing 
and selling a competing machine were activities outside the experimental 
use exemption.  So much for making various patented antennas to compare 
them on a test range, if you're in the antenna business at all.

Later, the experimental use exemption started to get bigger, but then, 
it totally clamped down in the 80s, largely because of some cases with 
respect to drug patents.  They pointed back to the early 1800s cases and 
said the dilettante curiosity expressed by Justice Story was in no way 
similar to someone who has any potential gain from the experimentation. 
  I don't recall all the details, but the bar was set pretty high to be 
able to claim the exemption.  Even writing a scientific journal paper by 
researchers who had no connection to any of the entities comparing the 
performance of various patented drugs or techniques was held to be 
infringing.  Basically, they removed the "intent" aspect of 
infringement.. if you duplicate the patented thing, you've infringed, 
and basically you have to hope that the patent owner can't establish 
significant damages.  However, in practice, the legal fees alone in 
mounting a defense would probably cripple most folks.

The courts  went back to the original "idle curiosity" or "amusement" 
and read it pretty narrowly... a researcher writing paper benefits (in 
reputation, grant awards, etc.) from the infringement of the patent, so 
they can't claim the experimental exemption. There's a case from Duke 
University and the inventor of the Free Electron Laser, for instance, 
notwithstanding that Duke is non-profit, etc.  As one writer commented: 
"any experiment that had a specific purpose or goal would fail both the 
'idle curiosity' and the 'business objective' tests."

So basically, you can knock yourself out making fractal antennas in your 
backyard as long as you don't tell anyone about them or hope to benefit 
from it.

Therefore.. there's not much incentive to go out writing QST or QEX 
articles, is there... Lots of potential downside (defending against an 
infringement lawsuit from Dr. Cohen) vs very small upside (a few hundred 
bucks from ARRL?).

Think about it.. if you want to experiment and write for QST, there's 
lots and lots of topics you could fool with, so why pick one where 
you're almost certain to get stuck in a mess.

You could even be bold and do your experiment and put it on a webpage, 
with no overt objective other than idle curiosity. And you might get a 
letter from Dr. Cohen's attorneys, asking you to take your web page down 
(I have heard it rumored that this has happened, but haven't been able 
to verify it.  It's possible that the letter made an offer the website 
couldn't refuse: "we won't sue you, which would cause you to spend 
thousands of dollars defending yourself, if you take the website down 
and shut up about it")

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