Hughes Aircraft Company

Hughes Electronics Corporation

Eng-Chong Ha

Parthasarathy Ramanujam

Donald C Chang

Thomas A Bockrath

A pair of dual-gridded shaped reflectors (10) and (20) are arranged one behind the other for transmitting and receiving orthogonally polarized energy waves. A front reflector (10) has a first shaped reflective surface (12) formed on a first body surface (14) for providing a first shaped beam coverage. A rear reflector (20) has a second reflective surface (22) formed on a second body surface (24) for providing a second shaped beam coverage. The first and second reflective surfaces (12) and (22) have substantially identical surface contours and include reflective grids (13) and (23). The reflective grids (13) and (23) are orthogonal with respect to each other so as to handle orthogonally polarized energy. The first and second shaped reflective surfaces (12) and (22) are arranged offset and tandem from each other so as to provide first and second focal points (16) and (26) separate from each other while providing substantially identical first and second shaped beam coverages (15) and (25). As a result, the front and rear reflectors (10) and (20) may be fabricated with a single mandrel (30).

Identical surface shaped reflectors in semi-tandem arrangement

An adaptive antenna 10 embodying the present invention includes an array of sensors 12. Each sensor 12 has associated therewith a main channel 14, a feedthrough path 16 and a feedback path 18. Correlators 20 coprocess signals in the feedthrough path 16 and the feedback path 18; the result is transformed according to an algorithm by a computer 22 which controls a weighting circuit 24. The weighting circuit 24 thus progressively modifies the signal in the main channel 14 to minimize interference with a desired signal. Placement of a limiter 26 along the feedback path 18 simplifies correlator design relative to adaptive antennas without such limiters and improves performance relative to adaptive antennas with limiters in the feedthrough path.

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Torrance, CA, United States of America

Eng-Chong Ha