The present invention relates to an antenna feed arrangement capable of providing a zero reflection response at a first frequency of interest and a maximally flat response at a widely separated second frequency of interest. The feed arrangement comprises a smooth-walled waveguide section at a first end, a corrugated waveguide section at a second end designed to provide the zero response at the first frequency, and a quarter-wave transformer waveguide section disposed between the smooth-walled and corrugated waveguide sections designed to provide the maximally flat response at the second frequency. The quarter-wave transformer section comprises a plurality of N corrugated waveguide subsections, where N.gtoreq.2, which comprise corrugation depths corresponding to the corrugation depths in the corrugated waveguide section. Additionally, the gaps between corrugations differ in adjacent subsections in a direction away from the entrance waveguide section and have a predetermined gap ratio between adjacent subsections.