Hello friends!
I don't know how much you feel free with fractals and fractal antennas(FA), so a few words about.
Fractals in electromagnetics is a new exciting topic, it was found that FA offers some improvements to classic antennas. Note that fractal is a strongly irregular structure, very complex and self-similar. There is a big difference opposite of "clasic" ideally smooth, Euclidean geometry - fractals have a non-integer so-called fractal dimension. They are a "natural" product of Nature, i.e. trees, clouds, seacosts are of course fractals. I can write many things about it...
Thanks to it fractal antennas then have next useful properties:
-They are multiband (one small antenna can support GSM900,GSM1800,UMTS,PCS1900 and BLUETOOTH!!)
-Their size can be much smaller than classical antennas (i.e fractal patches) ant they are still effective radiators
-Possibility to control gain
-...and others.
So it's my interest to study its behaviour, there is many non-answered questions at this field.
As a little example I attach two files:
1) Current distribution at Koch snowflake fix antenna (iteration level 3) at higher operating mode. Interesting fact is that the electric current is mainly localized at the fractal boundary. Current there has big density and the behaviour is like antenna array which results in higher gain. Of course, this antenna is also multiband. Computations were taken with IE3D, geometry created by self-made generator in MATLAB.
2) Analysis of Koch snowflake fix antenna (iteration level 5) based on cavity model. MATLAB+FEMLAB is used to calculate eigenvalues and eigenfuctions of this geometry. Presented picture electric field at 45th eigenmode. The behaviour is strictly different of, for example, rectangle, circle and so on.
I have many papers about this topic (and there exists many www pages too) and I hope that there is some antenna researcher which experiencies in with.
Nice weekend,
Eirp
**broken link removed**
<font size=-1>[ This Message was edited by: eirp on 2002-02-16 12:32 ]</font>