Guilin Sun
Ansys Employee

Please elaborare more regarding to the discrepancy: what the mesh accuracy and PML thickness you used? does the simulation run long enough and reach the autoshutoff min? how many k-vectors you used in RCWA?

They are two different solvers with different source of errors. Some discrepancy is common, if both of them are not approaching theorerical results, eg, due to using finite sampling.

In addition,what result is different? the diffraction angles, the diffraction orders, or the diffraction efficiency or anything else?