David Jefferies wrote:
> Hmm. The interaction of character with a not-very-sound idea about bent wire
> antennas hasn't been very helpful in this case. It IS possible to shrink an
> antenna dipole by periodically bending the wires. See my articles in
> antenneX on the zagis. You can't make a true fractal antenna as the wire
> would be indefinitely long and the efficiency would tend to zero with the
> losses. But this is not the way the authors use the word "fractal" so I
> think you might say there is some sense to the proposals.
I think the fractal antennas really refers to something with some amount
of scale invariant self similarity, using one of the standard fractals
as a basis, e.g. Sierpinski gasket. I believe the fractal antenna folks
have a variety of iterated functions that are used in their designs.
As many have commented, there's some fundamental physics limits to any
small antenna, and most designs work pretty much about the same, so you
need something to distinguish your particular flavor of multiband small
antenna from some one else's. Fractals are as good as anything else.
And, if the goal is just "good match over wide bandwidth" without a lot
of concern for absolute efficiency, then something that distributes loss
over the whole structure might be more appealing than something simple
like a 5 dB pad in the feed point to guarantee a 2:1 match. There's an
awful lot of systems applications out there that would gladly trade DC
power for simplicity of operation (e.g. the T2FD wideband antenna)
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