A 3-D FEM based segmentation method for the full-wave analysis of passive microwaves circuits

Introduces a method of analysis of passive microwave circuits based on 3-D FEM and the segmentation technique. Each one of the regions in which a global problem is divided is studied by using a formulation that leads to a system of equations with a symmetric sparse matrix which is independent of the number of modes used. Because of this, it is possible to increase or decrease this number at a negligible computational cost and to obtain efficiently the generalized admittance matrix (GAM) from the resolution of a lower triangular system, without the need to calculate the field distribution in an intermediate step. The regions are minimized by using the segmentation technique and including sections of waveguide analytically, since their GAM or generalized scattering matrix (GSM) are known. The connection of the regions is achieved by linking GAMs, or GSMs obtained from the GAMs. In order to increase the capability of segmentation, cylindrical ports connected by means of radial waveguides are included. The work has been also extended to inhomogeneous ports by using 2-D FEM to calculate numerical modes, but in this case, the efficiency decreases.