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A SHAPED REFLECTOR AS A PRIMARY FEED FOR HAYSTACK
MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB
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The paper describes a technique for obtaining high aperture efficiency in the Haystack 120-foot diameter Cassegrain antenna system. The approach used seeks to maximize the percentage of power intercepted by the hyperboloidal subreflector of the Cassegrain antenna system by shaping its primary feed radiation pattern. The primary feed configuration is a linearly polarized waveguide feed illuminating a specially shaped reflector. A number of theoretical antenna models were calculated and one of these antennas a 30 wavelength diameter shaped reflector at 7750 Mcps was fabricated and evaluated. Calculated estimates of percentage of primary feed power intercepted by the subreflector and Cassegrain aperture efficiency are presented.
APPROVED FOR PUBLIC RELEASE