Niki Papachristou
Ansys Employee

Hi Soufiane,

Thank you for reaching out to us! Your question is very interesting, I believe you can find a lot of guidance going through these two articles: Selecting the best mesh refinement option in the FDTD simulation object and Understanding Mesh Refinement and Conformal Mesh in FDTD. Also note that it is normal not to know the exact mesh settings for your simulation on your first try. It can end up on a trade between time memory and accuracy. For that reason we recommend to do a Convergence testing process for FDTD simulations.

Kind Regards,