Aperture mode filter

摘要

A mode filter for an antenna having at least one element aperture is provided. The mode filter includes at least one waveguide extension to extend the at least one element aperture, and at least one two-by-two (2 x 2) array of quad-ridged waveguide sections connected to a respective at least one waveguide extension. When the at least one waveguide extension is positioned between the at least one element aperture and the at least one two-by-two (2 x 2) array of quad-ridged waveguide sections, undesired electromagnetic modes of the antenna are suppressed.