On Monday, 6 April 2015 11:45:01 UTC+1, Capitol wrote:
Testing can be quite close to the calculation, but gain figures are
never posted. Fractals seem to suffer from lots of notches in the
response curves as a result of repeating one fixed shape. I was hoping
someone here had some hands on experience of performance.

I tried designing one a few years ago when I needed a wide bandwidth.
In the end the results were disappointing and I gave up and used a
more "conventional" structure where it is more obvious how any particular
adjustment will influence the characteristics.

I used EM simulation followed by testing prototypes with a VNA.

One of the biggest problems is that an antenna design that needs
to fit in an enclosure with nearby circuitry is difficult to
simulate accurately and therefore requires trimming. If you
can't predict what effect a particular adjustment will have,
the process becomes painful.

Obtaining a good return loss for transmitter matching is easy if
you use the procedure favoured by some manufacturers: just use
several metres of lossy coax between the antenna and the analyzer.

John