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US 3,938,159 AGranted
Dual frequency feed horn using notched fins for phase and amplitude control
AssigneeHughes Aircraft Company
InventorsJames S. Ajioka, Kenneth L. Schaffer
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AssigneeHughes Aircraft Company
InventorsJames S. Ajioka, Kenneth L. Schaffer
Estimating the term…
A dual frequency band horn-type antenna feed is described which has primary application to optimally illuminate a parabolic cylindrical reflector operating simultaneously at high power in both of the two bands. The principle of the invention is applicable to any two frequency bands regardless of their frequency separation including coincidence as a limiting case. The basic requirement of such a feed is that it must be as directive as possible within constraint of the feed aperture size in the plane of the cylinder axis because the cylindrical reflector does not collimate the beam in this plane and it must be relatively nondirective in the plane of the parabola for efficient illumination of the reflector. This requirement requires the phase front in the directive plane to be controlled within a small fraction of a wavelength at both frequencies.
An antenna element comprising a horn-type radiating element, means for exciting said horn-type radiating element with two orthogonally polarized signals from a higher and a lower frequency band, and means for providing a plurality of conductive fin pairs on opposing inner surfaces of said horn-type radiating element in a plane parallel to that of the polarization of said signal from the higher frequency band, said conductive fin pairs having a plurality of notches disposed along the adjacent edges thereof having a nominal depth of one-quarter wavelength at the frequency of said polarized signal from said higher frequency band.
A dual-frequency feed horn comprising a rectangular horn having a throat extremity and an aperture, means for exciting said throat extremity of said rectangular horn with two orthogonally polarized signals from a higher and a lower frequency band, and means for providing a plurality of conductive fin pairs along opposing inner surfaces of said rectangular horn between the throat and aperture thereof, in planes parallel to that of the polarization of said signal from the higher frequency band, said conductive fin pairs each having a plurality of notches disposed along the adjacent edges thereof having a nominal depth of one-quarter wavelength at the frequency of said polarized signal from said higher frequency band.
An antenna element comprising a horn-type radiating element, means for exciting said horn-type radiating element with two orthogonally polarized signals from a higher and a lower frequency band, and means for providing a plurality of conductive fin pairs on opposing inner surfaces of said horn-type radiating element in a plane parallel to that of the polarization of said signal from the higher frequency band, said conductive fin pairs having a plurality of folded notches disposed along the adjacent edges thereof.
A dual-frequency feed horn comprising a rectangular horn having a throat extremity and an aperture, means for exciting said throat extremity of said rectangular horn with two orthogonally polarized signals from a higher and a lower frequency band, and means for providing a plurality of conductive fin pairs along opposing inner surfaces of said rectangular horn between the throat and aperture thereof, in planes parallel to that of the polarization of said signal from the higher frequency band, said conductive fin pairs each having a plurality of notches disposed along the adjacent edges thereof and additionally including notches along the edges thereof in the plane of said aperture for shaping the beam radiated from said horn.
Dependencies are inferred from the claim text.