[Qucs-help] qucs microstrip related queries and dialogue box error

[William F. <fl...@at...>]

Dear qucs-support,

I hope you can help me with the following query please.

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:
<Microstrip>
   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
</Microstrip>

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.

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

ZL=real(sqrt(A[1,2]/A[2,1]))

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 (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?

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?

Thank you for your assistance,

Best regards,

Will Flynn.