Photonics

Photonics

Ansys Insight: About override mesh in FDTD: its use and settings

    • Guilin Sun
      Ansys Employee

      Many users ask if they can just make a curved surface smoother using override mesh, eg:

    • Guilin Sun
      Ansys Employee
      More than one override mesh regions: In some cases more than one override mesh is needed. Due to the meshing mechanism, from finer mesh to coarser mesh, it has gradual change. By default it has the graded factor. Therefore, for layered structures or when you add two cascaded override meshes, the actual mesh will not behave as expected. For example, one layer has a thickness of 30nm, and the other has 70nm. You add two override regions: one has 3nm mesh size and the other has 7nm. the result will have some graded meshes from the finer mesh 3nm to 7nm.
      It is usually not necessary to have too many override mesh regions. for example in the simulation region you have 10by10 rods, you do not need to add 100 override mesh regions. One should be enough, except that the spacing between the rods is very large.
      I would suggest to test the meshing if you have complicated structure and more than one override regions. Please note that the override region will have one mesh buffer.
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