Combined SEP and VEP in MoM

Hello,

I would like to perform a simulation of a rectangular piece of metal with half of it being solved with the Surface Equivalent Principle method, and the other half being solved by th Volume Equivalent Principle method.

Would this be possible ? I wonder how to tell FEKO that the two blocks actually form one big block. I have the feeling just making the two part at the same location won't work.

Is this possible ? And if so, what is the process to do so ?

Thanks,

Pierre

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Mahan Rudd_22044

Hi @degleve_jarmlami ,

SEP and VEP are not supported in the same model.

SEP formulation in Feko can be used to solve PEC or dielectric regions.

Finite conductivity metallic medium can be assigned to faces with no thickness. When dealing with a closed geometry the region must be set to free space first (closed shell) before metallic material properties can be assigned to the faces.

VEP can be used to solve the dielectric regions.

So what you can do:

Define the metallic medium that you want to solve with VEP as a dielectric.

Define the metallic medium that you want to solve with SEP as metal. I am basically suggesting to solve it with normal MoM rather than SEP.

Split the bigger block into two pieces (Construct—>Modify—>Split)

Change the region on the block you want to solve with VEP to the dielectric (I mean the metal material that you defined as dielectric) you defined earlier and set the solution to VEP.

Delete the common face on the other block. this will change the other block to an open geometry. there will be no region setting and the geometry is basically a couple of faces. Select those faces and set the properties to the metallic medium you defined earlier. You also need to define the thickness of the metal. These faces will be solved with normal MoM.

I tested this on a small model at a low frequency and can confirm that the simulation finished without any error. Whether or not this would work for your case depends on the model (size…) and frequency. I noted for larger model size and at higher frequencies meshing the model is challenging and requires lots of resources.

I hope this would help.

Regards

Mahan

degleve_jarmlami

Hello,

Thanks for your answer.

I am not sure to perfectly follow you. Are you saying that since I can't use both SEP and VEP, I can just define VEP on one volume and VEP on a bunch of surfaces, which will be equivalent to having SEP on those ? So I can roughly still combine both ?

And for more context : I cant to use VEP because I want to modelise skin depth effect. However, when applying metal to a face it asks for a thickness. However, this thickness should be both higher than skin depth, and smaller than the triangles. Problem is when my triangles are of the size of the skin depth I cannot compute anymore. I think I don't have this problem with the 3d MoM !

Mahan Rudd_22044

Hi @degleve_jarmlami ,

Since SEP and VEP are not supported in the same model this (VEP+faces with metallic material properties and thickness setting) is an alternative approach.

Regards

Mahan

degleve_jarmlami

Okay, thanks I'll give it a try. :)