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Professor Hussain Al-Rizzo

Dispersion Diagram of a Unit Cell of a Periodic Structure

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Hi,
I am trying to introduce to my students on how FEKO is used to simulate the dispersion diagram of the well-known unit mushroom cell developed by Sievenpipper as reported in Fig. 10 of attached paper. Results from CST is attached for reference. I wonder if Altair have any such model model or tutorial with procedure outlined for such an application.
 
Thank you and best regards

Hi_imp_sievenpiper.pdf

Sievenpiper_modes.bmp

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Attached an example Sievenpiper.cfx, based on the paper. I did not take into account the dimensions/distances in the paper, but you can can change these easily by changing variables ra, h (distance to ground) and distance (spacing between the hexagons).

image.png.bbe7dac2add64201a715ef0a093f0b2c.pngimage.thumb.png.aed662488735e73cf14256791240eb15.png

Sievenpiper.cfx

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Hi Dr. Torben,

 

Thank you for your kind reply. I ran the model, however, the problem that I am seeking is an eignevalue problem and the geometry is not the FSS you have used. The geometry is a grounded substrate with a via and conducting patch on top. Then the natural modes are usually found from an eigen mode solver after adding an air layer and PML. There is a lengthy procedure to follow by varying the phase among three periodic axes called Brillouin zone (from solid state physics). The final results are represented by a dispersion diagram frequency versus phase for a number (usually three) for TM and TE modes. I have searched the literature on FEKO and dispersion diagram and did not find results reported using FEKO. Currently, Lumerical, CST (application note attached), and HFSS have separate eignemode solver to perform such calculations.

 

Therefore, I wonder if you can solve this problem using FEKO?

 

Thank you and best regards

Dispersion_diagram_Appn_Note.pdf

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Hello Professor Hussain Al-Rizzo,

 

I was only concentrating on the creation of the infinite structure like shown in Hi_imp_sievenpiper.pdf

image.png.dd63b8c65ca9f3ee5b0a5d964b4bf482.png

 

Regarding the option of dispersion diagrams of infinite (Periodic Boundary Condition) structures in FEKO, there is a feature request under discussion. This feature request was originally started from an email from you to FEKO Support in November 2012 :) I will in any case keep you updated if there are good news for you.

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