Metal-insulator-metal waveguide based passive structures analyzed by transmission line model

In this work, we present an accurate coupled transmission line model for different metal-insulator-metal waveguide based arrangements. The coupling regions are modeled by appropriate characteristic impedances and propagation constants for both even and odd modes, which are calculated from the metal-insulator-metal waveguide parameters. The effectiveness of the transmission line models is investigated by using fully numerical finite element method (FEM). Our theoretical transmission line models are in good agreement with FEM based COMSOL simulations.