Earth coverage reflector antenna for geosynchronous spacecraft
AssigneeLockheed Martin Corporation
InventorsEdward Jay Kent, Mysore Srinvasa Iyengar Sheshadri
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Abstract
A reflector antenna for use on a geosynchronous spacecraft or satellite for providing Earth coverage has a gain or directivity which is two or three dB greater at the edges than at the beam center, to provide coverage with more or less uniform field strength at the Earth's surface. The reflectors may be based on diverging prime focus or offset-feed parabolas, in which case the reflective surfaces of shaped reflectors have, in at least one plane, a central convex region and an “edge” convex region, separated by a concave region. The reflectors may be based on converging prime focus or offset-feed parabolas, in which case the reflective surfaces of the shaped reflectors have, in at least one plane, a concave central region.
Claims7
A reflector antenna, said antenna comprising:
- a feed radiator for producing a directive feed beam;
- and
- a shaped reflector intercepting said feed beam of said feed radiator, said reflector being shaped for generating a generally axially symmetric beam about an axis, having a gain of about fourteen to fifteen db at the beam center, increasing by about three to four dB at angles of about 9° from the axis.
A reflector antenna, said antenna comprising:
- a feed radiator for producing a directive feed beam;
- and
- a shaped reflector intercepting said feed beam of said feed radiator, said reflector being shaped for generating a generally axially symmetric beam about an axis, and having a gain of about fourteen to fifteen db at the beam center, increasing to about eighteen dB at angles of about 9° from the axis, said shaped reflector having a surface contour in at least a first plane which includes a generally central convex region as seen from the feed side of said reflector, said surface contour also including a further convex region near the outer edge of said shaped reflector and a concave region lying between said central convex region and said further convex region.
Dependencies are inferred from the claim text.