Am Do, 25.02.2010, 18:12 schrieb William Flynn:
> Dear qucs-support,
> I've very recently discovered and started using QUCS which is a great
> software tool. I wanted to do some parameter calculations for a microstrip
> line, which I did using the QUCS transcal tool. I entered the various
> parameters and ran the analysis which gave me a value for the line
> impedance which is what I'm interested in. I saved the transcalc
> parameters, pasted here as for reference:
> Er 3.4 NA
> Mur 1 NA
> H 50 um
> H_t 2.54e+18 mm
> T 30 um
> Cond 5.813e+07 NA
> Tand 0.0019 NA
> Rough 0.0024 mm
> Freq 10 MHz
> W 80 um
> L 1000 mm
> Z0 57.1415 Ohm
> Ang_l 17.8917 Deg
Very odd geometry actually (almost square line on very thin substrate
which I think noone can produce....).
> I don't know what "H_t" parameter is, any ideas? I looked online but
> couldn't find anything. I used the default value given in transcalc and
> converted it instead to mm.
H_t is the metallic cover height. Make it very high, if there is
> I then copied the parameters in transcalc to the clip board (copy to
> clipboard, under transcalc's EXECUTE menu) and inserted in my QUCS
> schematic. I would like to see how the impedance changes with frequency.
> A dumb question I realise, but how do I do this , what do i plot ? The
> default equation that gets pasted in to my schematic window is
> Assuming that this is the impedance, if I plot this I get a different
> value to what the transcalc calculator calculated, eg. calculator said 57
> Ohms, Zl shows 54.67
That can happen, since maybe calculation in transcalc little bit different
Also you can enable "SaveCVs" in S-parameter simulation box to let
the microstrip line output it's characteristics (e.g. Zl).
> (if i go out to a larger number of digits, only see a
> change in the 4th or 5th decimal place over the frequency sweep). Does
> this make sense?
Haven't tried yet, but I think it's because of the odd geometry...
> I displayed the data in table form and graph form. I wanted to export the
> data to .csv format. If I select the graph or table and use the "Export to
> CSV" option in the project menu, I get the Error dialogue box telling me
> to "Please select a diagram graph!" but that's just what I've been doing.
> any ideas?
Well I think you can only export it in graph, not in table. Then select
a graph, not the diagram...
Best regards, Stefan.