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Old September 6th 03, 08:19 PM
totojepast
 
Posts: n/a
Default Are fractal antennas being used in cellphones?

According to the July 1999 issue of Scientific American (available
online at
http://www.sciam.com/article.cfm?art...B7809EC588F2D7),
Motorola started using the fractal antennas inside its cellphones. Do
they still use them? And what about the other manufacturers?

"(....) Cohen, who founded Fractal Antenna Systems four years ago, is
now working with T&M Antennas, which makes cellular phone antennas for
Motorola. T&M engineer John Chenoweth says that the fractal antennas
are 25 percent more efficient than the rubbery "stubby" found on most
phones. (...)
Just why these fractal antennas work so well was answered in part in
the March issue of the journal Fractals. Cohen and his colleague
Robert Hohlfeld proved mathematically that for an antenna to work
equally well at all frequencies, it must satisfy two criteria. It must
be symmetrical about a point. And it must be self-similar, having the
same basic appearance at every scale--that is, it has to be fractal."