Analysis of Waveguide Discontinuities by Mode Matching Method

Abstract

<p>An effective mode matching method (MMM) is developed for dealing with three- dimensional (3D) dielectiic waveguide structures with arbitrary transverse index profiles and scattering interfaces along the longitudinal waveguide axis. With the introduction of a perfectly conducting box coated by a perfectly matched layer (PML) as the lateral boundary, the method circumvents the inherent difficulties associated with the continuous radiation modes of open waveguide structures. The semi and full-vectorial finite difference (FD) methods are employed for mode calculation. The guideline for choice of the PML parameters in the mode matching analysis is discussed via a two-dimensional (2D) waveguide structure with a single step discontinuity. We show results for the 3D waveguide air gap, facet and polarization converter. The effectiveness and efficiency of the method are validated.</p>