Trw Limited

Northrop Grumman Systems Corporation

Louis C Wilson

Charles W Chandler

Ann L Peebles

Makkalon Em

An antenna system that employs an antenna element for both transmit and receive functions, where a dual band polarizer is used to convert linearly polarized signals to circularly polarized signals and vice versa for two frequency bands. The dual band polarizer includes a waveguide including corrugated structures extending from opposing sidewalls, where ridges in the structures extend perpendicular to the propagation direction of the signal. The height of the ridges taper from a lowest height at the ends of the waveguide to a largest height at the middle of the waveguide. The corrugated structures interact with the field components of the signal in the direction perpendicular to the ridges that cause that component to be delayed relative to the field components parallel to the ridges so that the signal changes accordingly and maintains the same magnitude.

Dual band frequency polarizer using corrugated geometry profile

A steerable antenna comprises a steerable main reflector and a stationary feed assembly and subreflector assembly configured in a side-fed configuration where the feed assembly is to a side of both the main reflector and the subreflector. The main reflector, subreflector and feed assembly together produce an antenna beam which is directed in a preselected direction by the main reflector. A gimbal is coupled to the main reflector for positioning the main reflector and scanning the antenna beam over a preselected coverage area while the feed assembly and subreflector remain substantially stationary.

Side-fed offset cassegrain antenna with main reflector gimbal

An antenna system comprising a feed array, a subreflector and a main reflector which are oriented to define a side-fed dual reflector antenna geometry. The feed array is comprised of a plurality of separate feeds which are aligned on a predetermined contour. Each feed array is coupled to a feed network which acts to combine the illumination beams of clusters of a preselected number of feeds to produce a plurality of composite illumination beams. Each composite illumination beam is directed to be incident upon a separate preselected location on the subreflector which directs the composite illumination beams towards the main reflector. Each composite illumination beam is reflected by the main reflector in a preselected direction so that each composite illumination beam forms an antenna beam that impinges a predetermined coverage area on the Earth. Each antenna beam defines a separate coverage cell in the coverage area, wherein the position and orientation of the feeds, the subreflector and the main reflector provides antenna beams over a full Earth field of view coverage area where each antenna beam is approximately symmetrically shaped.

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Canoga Park, CA, United States of America

Louis C Wilson