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The simultaneous but independent development in the United States and Australia of circular-aperture corrugated horns in the early 1960's is reviewed. The features of this development include the wide flare-angle corrugated "scalar" horn and the characteristics of focal-region fields of reflector antennas and the single- and multimode cylindrical corrugated horns necessary to feed them.
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B. Thomas (1986) studied this question.
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