Novel method of lines approach combining 2D and 3D analysis

In this contribution a new algorithm based on the method of lines (MoL) is presented. Here the usual 3D MoL approach is extended by adding a 2D analysis of critical parts of the structure, which require a very fine meshing to resolve all fine details or to incorporate loss in an appropriate way. The 3D approach is based on an eigenvalue computation based on a 2D discretization. The 2D eigenvalue calculation based on a one-dimensional analysis gives much more accurate results compared to the 3D approach. In the combined approach only for some selected modes the additions 2D analysis is performed, the eigenvalues of the 3D approach are updated by the more accurate vales. In this way the accuracy of the method can be improved significantly. This will be shown at the example of a lossy underpass in a transmission line, which may occur in RF MEMS switches, contributing much to the overall loss of such a switch. Nearly the same accuracy in only one tenth of the calculation time is achieved.