A numerical method for the computation of reflection and transmission in slowly evolutive wave guides

The evolution is approximated with steps which are cylindrical waveguides of any shape made of several absorbing materials. The modes in the different steps are computed with the finite element method, and the scattered matrix of the slowly evolutive waveguide is obtained with the mode matching method. The originality of this formulation is the electromagnetic field decomposition on special real bases. The propagation constants and the fields of each guided mode are computed with the same bases functions for a range of frequencies and for materials having closed electromagnetic properties. This particularly decreases the computation time and is well adapted for parametric investigation. The general code has been validated for the case of rectangular waveguide functions. In the validations, calculations have been performed with the same bases for the 8-12 GHz band.<>