Meshing is the process of converting the continuous domain into the discrete domain for solving the equations. For discretizing surfaces, typically either triangles or rectangles are used. Antenna Toolbox™ uses triangular element for meshing metal antennas and tetrahedra for meshing dielectrics. Both the above methods conforms better for arbitrary shaped surfaces. The triangles are used to approximate the surface current using the Rao-Wilton-Glisson (RWG) basis functions. To get an accurate result, ensure that large number of triangles are present in the region where current variation is the highest. This region is typically either the corners in the antenna geometry or at the point where the antenna is excited.
Method of Moments (MoM) is a numerical method that transforms Maxwell’s continuous integral equations into an approximate discrete formulation that requires inversion of a large matrix.