How to extract s-parameter of my nanowire hyperbolic metamaterials

Dear Enginer now I wanna get my effective index from my nanowire hyperbolic metamaterials(HMM), with nanowire being Au and the host being dielectric.
My fsp file is shown below.
s.fsp (591.6 KB)

The ideal HMM span should extend to infinity. I just set the y&z boundary condition being periodic and the x span of HMM being 1.5 micro meter. The problem is that, when my file is running over, the s-parameter analysis reports that there are too many spatial variations in the field so that my results look weird.

What should I do? Is that out of the Au metal nanowire extends to FDTD y&z boundary?(But they are set periodic !)
Thank you very much!

Could anyone come to help me and why my previous topic “meta” has been changed?

I am guessing that it could be the bulk parameter extraction method. By default, we have Smith’s method but this is not a method that can solve all parameter extraction problem. I think you may need to look for some other bulk parameter extraction method in the literature. I will reply your question in your chinese post with more detials (从nanowire hyperbolic metamaterial 里面获得s parameter).