A polarizer for a dual frequency band is formed of square waveguides of a dual structure. A section is formed which extends in a step-like manner as deeper inside between outer and inner square waveguides. The section is connected to the inner square waveguide at an output portion. A third section protrudes...http://www.google.se/patents/US6522215?utm_source=gb-gplus-sharePatent US6522215 - Converter for receiving satellite signal with dual frequency band
