Mode Filters for Oversized Rectangular Waveguides

In order to suppress trapped-mode resonances and other disturbing phenomena related to the existence of higher-order modes in oversized waveguides, suitable mode filters are required. In this paper such filters are described for rectangular waveguides in which only the dominant H/sub 10/ mode is wanted. The unwanted modes to be suppressed by the mode filters are classified as 1) E/sub mn/ and H/sub mn/ modes with n /spl ne/ 0, and 2) H/sub m0/ modes with m /spl ne/ 1. These two types of modes must be treated separately and require different approaches to the mode-filtering problem. For both classes several constructions of mode filters are described and analyzed.