Re: [Qucs-devel] Renormalization of S-parameters

[roucaries b. <rou...@gm...>]

On Wed, Jul 16, 2008 at 10:44 PM, Claudio Girardi
<cla...@vi...> wrote:
> Christian Friesicke wrote:
>  > Hey guys,
>  >
>  > the devel-list is probably not the best forum for a request like this
> but
>  > I have one rather simple question about the Qucs Technical Paper
> published
>  > at
>  >    http://qucs.sourceforge.net/tech/technical.html
>  >
>  > In the Mathematical Background you give a formula for renormalizing
>  > S-parameters to a new set of port impedances (formula 15.1).  Can you
> give
>  > me a reference (e.g., to an IEEE paper) where this formula comes from?
>  >
>  > I know of one reference,
>  >    JC Tippet, IEEE Trans. MTT, Vol. 30, No. 5, May 1982 (see Appendix
> V,
>  > formula (7))
>
> Hello,
> besides the one mentioned by bastien I might add also another nice
> paper, R. B. Marks and D. F. Williams, "A General Waveguide Circuit
> Theory," Journal of Research of the National Institute of Standards and
> Technology 97, pp. 533-562, Sep. Oct. 1992 which also deals with the
> problem of complex reference impedances.

Yes, a pretty good reference. A pretty good sum up of the two
approaches is the excellent anritsu note:
Application Note,
Arbitrary Impedance.
Accurate Measurements In Almost Any
      Impedance Environment

Qucs implement only real impedance S parameter. Complexd one are buggy
(even if we try to implement youla wave)

Regards

Bastien

>> My research is about nonuniform transmission lines, and I have tinkered a
>> lot with portions of code from Transcalc (microstrip, coupled microstrip),
>> which I ported to Matlab.  I have also done some improvements to the
>> stability of the code (analysis and synthesis).
>> Transcalc seems dead :( but luckily it is kept alive in qucs-transcalc.  I
>> decided to read the list here because I wanted to feed back some of my
>> improvements and ideas when time permits.
>
> Yes, the original transcalc has been sleeping for quite some time now,
> and will likely continue to live a new life as QucsTranscalc. If you
> have done any improvements to the code I will be anyway interested in
> them, as the developer of the original coupled microstrip code, code
> which proved to be quite difficult to implement without bugs... I think
> there still might be a couple of bugs which were corrected in
> QucsTranscal but not in transcalc.
>
> Regards,
>   Claudio
>
> -------------------------------------------------------------------------
> This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
> Build the coolest Linux based applications with Moblin SDK & win great prizes
> Grand prize is a trip for two to an Open Source event anywhere in the world
> http://moblin-contest.org/redirect.php?banner_id=100&url=/
> _______________________________________________
> Qucs-devel mailing list
> Quc...@li...
> https://lists.sourceforge.net/lists/listinfo/qucs-devel
>