Convergency study of an algorithm to design dual band polarizers

Mode matching based software has been developed to analyze dual band polarizers in a circular waveguide with corrugations in a rectangular guide, and its convergency checked. Two of the parameters affecting the convergency of the method are: number of integration samples and number of eigenmodes. The more important parameter affecting the convergency is the number of eigenmodes, since from n=40 (6400 integration cells), the convergency is reached for any number of eigenfunctions used within a range of 0.03% of error. The meaningful number of eigenmodes to perform predesigns is 28, 45 eigenmodes are necessary to reach an accuracy better than 0.01% and then to get a very accurate definitive design