Richard Clark wrote in
:

On Thu, 26 Mar 2009 09:35:06 +0100, Jon K Hellan LA4RT
wrote:

I'm very naive in these matters. Could a coaxial stub be modeled as a
cage of wires around the center conductor? Would the orders of
....
So, to your question:
Could a coaxial stub be modeled as a
cage of wires around the center conductor?
No, not if my experience bears any relevance.

Hi Jon, Richard,

I considered the same, and I did model some simpler structures to explore
some possible effects.

Although it would be possible to create a cylindrical structure of GW
elements, my concern was that it would not have the near complete
isolation of inner and outer surfaces of the outer conductor, that it
might need be be very large in diameter in terms of wavelength, and that
it moves further away from practical commercial coaxial lines.

I have been quiet here, but have been modelling and writing notes up on
the results. I have asked for comment on a draft model, and subject to
that, I will post the URL for further comments, hopefully in a day or
two.

The effort was really about understanding whether the stub in my fig a)
could simply be replaced by a pure differential mode transmission line,
and whether that could then be coaxially collinear with the main
radiator. I think the answer to the first question is NO, and that drives
the answer to the second question.

Owen