On Wed, Jul 16, 2008 at 10:44 PM, Claudio Girardi
> Christian Friesicke wrote:
> > Hey guys,
> > the devel-list is probably not the best forum for a request like this
> > I have one rather simple question about the Qucs Technical Paper
> > 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
> > 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
> > formula (7))
> 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:
Accurate Measurements In Almost Any
Qucs implement only real impedance S parameter. Complexd one are buggy
(even if we try to implement youla wave)
>> 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.
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