Meshing Region Vs. Problem Region

HFSS distinguishes between the problem region and the meshing region. The problem region is the region in which the solution is generated and the mesh is refined. The meshing region, which includes the problem region, is the area in which an initial mesh is generated. After an initial mesh is generated, the mesh is refined only in the problem region.

The problem region encompasses an area that is just large enough to include the entire design, but no larger. HFSS automatically defines the problem region during the solution process. If you are interested in effects outside of the structure, such as radiated effects, then you can create a virtual object to expand the size of the problem region to include these areas.

The meshing region, like the problem region, is a box that completely encloses the structure. However, the meshing region must be at least 10 times larger than the model. The part of the meshing region not occupied by objects is considered to be the background object. The background extends to the boundaries of the meshing region and fills in any voids not occupied by objects. Because the background object is defined as a perfect conductor, no solution is generated inside the background even though an initial mesh is generated for it. HFSS automatically defines the meshing region during the solution process.

The problem region and the meshing region are illustrated below.