Altair RISE

A program to recognize and reward our most engaged community members

Nominate Yourself Now!

Anisotropic slab plane wave incidence shift in E field when using FDTD

I am modeling a thin bi-axial anisotropic slab with plane wave illumination using FDTD solver. In order to validate result from FDTD I made the anisotropic tensor to be isotropic and modeled the structure using MOM-MLFMM solver. When I compared the near field results I find a shift in total electric field for certain observation points. I have attached the model and postfeko file for your reference. Can you please have a look at the FDTD solver model and let me know if I have to change any simulation settings.

Thanks,

Shan25

<?xml version="1.0" encoding="UTF-8"?>

Unable to find an attachment - read this blog

Find more posts tagged with

English

Feko

Accepted answers

All comments

Mel

Hi Shan

I don't consider the shift to be unexpected. Perhaps you just need a finer mesh.

But then again you need to model the same in both methods. The FEM also supports anisotropic materials. You could compare FDTD with FEM.

shan25_22144

Hi Mel,

Thanks for your reply. I tried modeling the structure using FEM solver. I get this error

ERROR 50058: Missing buffer zone for the anisotropic FEM region when coupling MoM and FEM

I don't have any MoM regions in the model. I get the same error message when enabling/disabling 'Decouple from MoM' in solver settings. Can you please explain the reason for this error message.

Unable to find an attachment - read this blog

Mel

Hi Shan25

The FEM, for anisotropic materials, does not allow an anisotropic material on the FEM boundary. The workaround is you must enclose the material with a FEM air (epsr=1) isotropic dielectric.

Please view the two videos encircled below on https://altairuniversity.com/learning-library/

It will show how it is done.

<?xml version="1.0" encoding="UTF-8"?>