An improved multi-port network model for multi-layer planar circuits

A fast computational method for multi-port network modeling (MNM) of multi-layer planar circuits containing slots is presented. A combination of the generalized network formulation for aperture problems and Okoshi's model for planar circuits is used to obtain a unified 2D circuit model for two planar circuits coupled through a slot of arbitrary shape in their common ground plane. This model can be used for design optimization of planar multi-layer circuits, such as filters. Compared to our previous work, 3D waveguide mode expansion is used to model the presence of the slot accurately. Some numerical results are presented and compared with more rigorous simulations by commercial software.