Advanced Mesh Strategies (Hexahedral)

In combination with the Finite Integration Method (FI-Method), CST EM STUDIO offers some advanced mesh strategies to provide a flexible and detailed spatial discretization of the structure. Here, it is necessary to obtain a sufficient mesh resolution of the simulated model, especially for small or critical regions with the constraint to minimize the resulting total number of mesh points.

Perfect Boundary Approximation

The Perfect Boundary Approximation (PBA) is used for the spatial discretization of the structure. The simulated structure and the electromagnetic fields are mapped to a hexagonal mesh. PBA allows a very good approximation of even curved surfaces within the cubic mesh cells.

PBA and mesh cell size

This works very well as long as the approximated structure is greater than the cell size of the mesh. Because, as in every discrete systems, the resolution of the method is limited by the sampling width. This means, that small details of the structure will be modeled accurately only if the mesh cell sizes are smaller than these details.

If PEC structure details are lower than the method’s resolution, PBA is not able to encounter non ambiguous locations of the discrete field values. In these cases the affected cell will be treated as entirely filled with PEC. With other words, for this critical cell, the structure will be artificially enlarged.

The pictures show a mesh plane with a cut polygon of the structure (violet). The black lines are the mesh lines and the bright blue squares represent the filled parts.

PEC structure elements smaller than mesh cell size.

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PEC structure entirely between mesh lines.

$image\fillup2.gif$

Note: As a result of this filling process, two conducting structure elements might become electrically connected whereas they were not previously. In the worst case, this will produce a short circuit in the structure. Therefore, it is recommended that you examine the mesh and refine these areas before starting the simulation.