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Re: Fractal antennas and Tesla coils



Original poster: Mark Fergerson <mfergerson1@xxxxxxx>

Tesla list wrote:

 Original poster: m.j.watts@xxxxxxxxxxxx On 20 Dec 2005, at 18:24,
 Tesla list wrote:

> Original poster: Aaron Banerjee <spam_proof@xxxxxxxxxxxxxxxx>
>
>
> I recently attented an interesting presentation on the use of
> fractal antennas. I was wondering if anyone was building coils
> designed to resonate at multiple, disparate frequencies (e.g. not
> just w, 2w, etc) or at least using coils with multiple resonances.
> I seem to have enough trouble getting my coil to resonate at one
> frequency, but I thought someone out there may have thought of the
> idea..
>
> Supposing for the moment that you were trying to do the wireless
> power thingy, could a broadband antenna help improve efficiency?
> If so, is there a good way to broadcast power (e.g. more than just
> enough for a voice/data signal, etc) through one? - Aaron Banerjee

 The receiver would have to be capable of receiving all those
 frequencies equally well. Moreover, the fact that it is broadband
 implies a lack of selectivity and in the case of a high powered
 impulse-driven transmitter, high-powered broadband splatter. Kind of
 like an out-of- tune TC. Not a popular device with the neighbours. I
 imagine too that group delay would become a serious issue when it
 came to efficiency.

 Malcolm

 I'd like to point out that Terry's plane wave antenna:

http://hot-streamer.com/temp/PlaneWave.pdf

is a decent approximation of a low-order 2D fractal. However, in its intended use there's no great voltage on it, whereas trying to use such a fractal structure as a Tesla _transmitting_ antenna (for which read: topload) means it'll need to be built using _very_ fat conductors to avoid breakout. I'm not saying it's impossible, just that there may be some minor technical difficulties in embodying the concept. ;>)

OTOH I'll also point out that there are other kinds of fractals, including 3D ones; a spheroid with hemispherical bumps (with littler bumps on them, ad infinitum) comes to mind, of which the Wardenclyffe tower's topload is a fair approximation.



 Mark L. Fergerson