Characterization of a class of waveguide discontinuities using a modified TEmnx mode approach

A modified TE_mn^x wave approach which is used in conjunction with the mode matching method for the field-theory modeling of a class of waveguide discontinuities is presented. In particular, for characterizing waveguide discontinuities in which resonant effects occur, this method resolves conflicting results which have been observed using the conventional TE_mn^x mode matching technique and the generalized analysis based on a linear superposition of TE_mn^z and TM_mn^x modes. It is found that results from the modified TE_mn ^x mode approach are consistent with the generalized analysis and agree well with measurements on iris filters and corrugated waveguide polarizers. In comparison with the generalized TE-TM mode analysis, the modified TE_mn^x mode procedure consumes less memory and CPU time and provides improved convergence behavior without sacrificing design accuracy