Optimization S parameters

Altair Forum User
Altair Forum User
Altair Employee
edited October 2020 in Community Q&A

Hello,
I have the following problem.
I would have to vary the variable epsr and tan_delta, respectively the electric and tangent permittivity of loss of the dielectric that I have in the rectangular guide, so that the scattering parameters are equal to measurements made with the VNA.
How can I set everything up with the optimization search?

I set the problem in the following way but by launching the simulation I had warnings.

Unable to find an attachment - read this blog

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Answers

  • Mel
    Mel Altair Community Member
    edited March 2019

    Hi John1989

     

    I don't see much wrong with your setup.


    But are you sure you want to vary the permittivity from zero onwards? Does not sound realistic. Maybe rather from 1 and up? Or are you trying something in terms of metamaterials?

    Also the tan delta varying up to maximum 1 is very high?

     

    What warnings did you receive? 

     

    To make the solution faster, you can set the horizontal plane of symmetry to electric.

     

     

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited March 2019

    Recapitulate the problem.

    I have measurements made with the VNA of the scattering parameters S11 and S21 with a configuration of a rectangular waveguide with a dielectric inside.
    I intend to quantify the relative dielectric constant and its loss tangent.
    So to get the latter I started by determining an initial value for the two, and then configuring an 'Add Search' where I configured two masks (one relating to the magnitude of S11 and the other relating to the magnitude of S21).
    In the 'Goals' I defined two goals: the two scattering parameters must be the same as the two masks I defined.
    In the 'Parameters' instead I made the two variables vary: epsr and tan_delta.

    I wanted to know:
    - Is it right how I set the problem?

     

    I put the configuration files back because I changed the model

    Unable to find an attachment - read this blog

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited March 2019

    Hello,
    in performing the optimization in CADFEKO I found this warning.
    How can I solve it?
    Do I need to change the minimum and maximum values of the parameters?

     

     

     

    <?xml version="1.0" encoding="UTF-8"?>Warning_OPTFEKO.thumb.png.0a51acf59e708ea16a536c706faa9234.png