CAD of complex passive devices composed of arbitrarily shaped waveguides using Nystro/spl uml/m and BI-RME methods

In this paper, a novel computer-aided design (CAD) tool of complex passive microwave devices in waveguide technology is proposed. Such a tool is based on a very efficient integral-equation analysis technique that provides a full-wave characterization of discontinuities between arbitrarily shaped waveguides defined by linear, circular, and/or elliptical arcs. For solving the modal analysis of such arbitrary waveguides, a modified version of the well-known boundary integral-resonant-mode expansion (BI-RME) method using the Nystro/spl uml/m approach, instead of the traditional Galerkin version of the method of moments, is proposed, thus providing significant savings on computational costs and implementation complexity. The novel theoretical aspects of this Nystro/spl uml/m approach, as well as their impact on the original BI-RME formulation, are fully described. Comparative benchmarks between this new technique and the classical BI-RME formulation using Galerkin are successfully presented for the full-wave analysis of frequently used irises (i.e., rectangular cross-shaped and circular multiridged) and for the CAD of complex waveguide components (such as rectangular waveguide filters considering mechanization effects and dual-mode circular waveguide filters with elliptical irises).