Finite Array

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

Hello, I am performing a finite array analysis using a unit cell element that I have created (due to reasons I can't post the actual element). I followed the example guides but am getting an the following error:

 

Error 16905: DGFM on Union2.Region36_1, Union2.Region36_2, Union2.Region34_2, Union2.Region34_1, Union2.Region96 cannot be specified with PO, UTD, large element PO or UTD, SEP and VEP.

 

The above regions in the error are all objects that types of dielectrics.

 

Also as a side question. Is there a simple way of exporting S-Parameter data like in HFSS (for MATLAB)? From what I have seen I have to use Fortran to get the data..

 

thanks

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Answers

  • Johan_Huysamen
    Johan_Huysamen
    Altair Employee
    edited June 2017

    Hi Jason

     

    The finite array solver (DGFM) should support dielectrics modeled with the (default) Surface Equivalence Principle (SEP). Please confirm that your dielectric Regions have this selected as the 'Solution method' on the Solution tab of the Region properties.

     

    I believe this feature was added in FEKO 14.0.430 so you might also want to check your FEKO version to ensure that it is this or a later version.

     

    S-parameters can be exported by selecting the 'Export S-parameters to Touchstone file (*.snp)' option on the S-parameter request dialog.

     

    Regards,

    Johan H

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited June 2017

    Also as a side question. Is there a simple way of exporting S-Parameter data like in HFSS (for MATLAB)? From what I have seen I have to use Fortran to get the data..

    You can change the setting in the model as Johan suggested but there are a few other options that might be helpful:

    • You can export a Touchstone file from POSTFEKO if you already have simulated data for an S-parameter request
    • If your problem is that you don't have a Touchstone reader/writer, then POSTFEKO has an API function that can write directly to *.mat files.  Se 'pf.MatIO.ExportMatFile' in the documentation for more information and an example. 
  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited June 2017

    EDIT:

     

    Johan and Andries, thanks for the answers. Johan I just looked through my model and all the dielectric regions are set to the default SEP.

     

    Also, a still relevant question. Say I have an unit cell element that has a finite ground plane that covers the entirety of the unit cell, where the wave port feed is located below the ground plane. If I setup a finite array I will get an error where it says that two triangles are touching without a common edge... Can I perform this finite array analysis where the edges of the ground plane touch the next unit cell without using an infinite ground plane, as is done in the examples? Since my feed is located below the ground plane I can't use an infinite ground plane.

  • Johan_Huysamen
    Johan_Huysamen
    Altair Employee
    edited June 2017

    Jason,

     

    Regarding the original error with the SEP regions, if you have the latest version of FEKO, we would not expect this error. Could you please confirm your FEKO version?

     

    For modeling the finite ground please note that the DGFM does not currently support array/unit cell elements that are touching. Unfortunately this includes the finite ground that you have added. As such, if you want to continue using the DGFM, you would have to find a way to model your feed above an infinite ground.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited June 2017

    Johan,

     

    I am using version 2017-293043 (x64)

     

    That is unfortunate that DGFM does not support unit cells elements that are touching and I don't think I can rework my model to be fed above infinite ground (at least not without major revision)

     

    Jason

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