[SOLVED] A small HFSS question: can't plot field on a non-model object

[kazbek]

Dear users,
the question is: how to plot a field cross-section in HFSS without disturbing model solution. If I just draw a non-model rectangle, I can't plot field on it - I got an error: "No plot can be generated because only non-model objects and/or faces have been selected". If I make this rectangle a model object, then it changes solution significantly, even though I don't assign any material. So I can't plot any field cross-secion in the place where I need.
Could anyone please give a hint?
The question was asked in the forums, but not answered, at least I couldn't find it.
Best luck, health and happiness to everone -_-

 

[khaled.ayman]

Dear users,
I got an error: "No plot can be generated because only non-model objects and/or faces have been selected"

Not really sure if I understand all your question, but whenever I get that error I just need to copy/paste my model in a new file then add whatever object I need, in that case you won't get an error.

 

[redcrystalline]

i had this question too

 

[jeeudr]

In order to plot the field at a particular location, I add a model object of of vacuum or whatever the default background material is. As long as it does not intersect with any other objects, it has never had a significant effect on the results of my simulation.

In any case, a non-model object cannot be used.

 

[redcrystalline]

hi
then what are non-model objects use?

 

[kazbek]

Many thanks to everybody for your replies!
Unfortunately nothing of what you proposed works for me. I created a rectangle which doesn't intersect anything in the model except for the vacuum box in which the whole model is located. I can plot field on this rectangle, but the resulting s-parameters dependencies on frequency look completely different from what they look like when there is no rectangle.
Assigning vacuum to the rectangle as jeeudr proposed is impossible. Then I created a box instead of rectangle and assigned vacuum to it. The result is the same: s-parameters curves look completely different compared to the case without any additional boxes or rectangles.
So, I would formulate the problem once again: I just want to plot field around a certain place in vacuum. How can I do it without disturbing the simulation (i.e. without disturbing s-parameter dependencies on frequency)?
Again, thanks for help, peace and harmony for everybody!

 

[redcrystalline]

could you upload ur project file?

 

[kazbek]

Here is the file. It's a CPW resonator, and I just want to plot field above the surface in YZ plane.

 

[redcrystalline]

the main problem with your structure is that it does not resonate !!!, are you sure about design?
ive done some modifications check it again please

 

[kazbek]

Thanks for your help, redcrystalline!
However what do you consider as an improvement in your model over mine? In my model mag(s(1,1)) dependence on frequency had a clear resonant character with resonances at full wavelength and half wavelength and with Q-factor (defined as peak frequency over the peak width at half the intensity) of about 10. mag(s(1,1)) drops from 1 to 0.55 at resonance. As far as I have noticed you just reduced the waveport's height and assigned an integration line to it. As a result in your model there are hardly any resonant peaks seen at all at mag(s(1,1)) vs frequency plot.
And the main problem is still unresolved: how to plot any field in the free space above my resonator?

 

[redcrystalline]

hi
in fact i have modified solver option not structure, by the way i'm not sure about your design solver convergence ,i believe that is the main problem, because when you add a non-assigned rectangular surface, design meshes change and so s-parameters change too! is n't?
to prove my idea i ll upload a example design later
regards
red

 

[kazbek]

Perhaps you are right with your suspicion about the convergence - when I make a solution there is a warning: Adaptive Passes did not converge based on specified criteria. And also my results changed a lot when I changed some parameters just a very little bit. Thanks a lot, Redcrystalline, thing start to clear up a little bit! But what is the cause of this convergence problem?

 

[redcrystalline]

hfss use adaptive solver, this means that software in first make meshes according to "solution frequency" and
changes meshes in every iteretion to converge error to assigned "Maximum Delta-S" maximum allowed iteretions are assigned by "Maximum Number of passes"
now what make you sure about convergence is located in HFSS>RESULTS>SOLUTION DATA>convergence
in this root you could find maximum magnitude of delta-S or relative error

 

[dpres]

You can with plot the field on non model in HFSS15. it is new.

 

[kazbek]

Looks like you just have to place the object you want to plot field on (rectangle for example) not very close to the electrodes. It's a partial solution of the problem, but looks like there is nothing better. Thanks everybody for help!

 

[kazbek]

It seems to me now I understand what the problem was. The problem was that the solution didn't tend to converge indeed, that's why any change to the mesh (which happens when you include a rectangle or whatever into your model) made a significant change to the solution (s-parameters in my case). After I solved convergence problem I could include rectangles that I wanted to plot field on without signifcant changes.