Richard Harrison wrote:
Roy Lewallen wrote:
"What`s fractal theory?"

The IEEE lists a paper appearimg in "Antennas and Propagation 2007".
EuCAP 2007.

Claims are size can be shrunk from two to four times without much loss
in performance, and that the antenna is naturally broad in bandwidth.
Two criteria must be met. The antenna must be symmetrical about a point,
and it must be self-similar, having the same appearance at every scale.

Dr. Nathan Cohen (Chip) is founder of Fractal Antenna Systems, Inc. He
is also a professor of Applied Science and Telecommunications at Boston
University.

Best regards, Richard Harrison, KB5WZI


As some of the longer term readers of this group might recall, the same
or superior characteristics can be obtained by shrinking antennas by
having their perimeters follow a random, rather than fractal, path. A
random meander pattern submitted by Dr. Steve Best, who also wrote
several IEEE papers on the subject, was shown to be superior to a
fractal design in the quality factor criteria put forth by Chip in a
"challenge" the latter publicized here some years ago (2000). Anyone
interested is encouraged to go to http://eznec.com/misc/MI2/, read the
0Notes.txt file, and download and look at the various competing designs.
The designs are in the form of EZNEC files, which can be viewed with any
EZNEC program type including the demo.

But this doesn't explain what "fractal theory" is, unless it means the
creation of antennas whose perimeters follow a fractal curve. In that
case, "fractal theory" hasn't been shown to be superior to "random
theory", and in some ways really no better than "square theory" or
"round theory". Sounds a lot better when trying to talk potential
investors into reaching for their wallets, though.

Roy Lewallen, W7EL