Ford Aerospace & Communications Corporation

Space Systems/loral, LLC

William G Scott

Howard H Luh

Edgar W Matthews, Jr

Charles A Klein

A method for predicting and compensating for angular beam misalignment of an antenna (101) due to antenna shape distortion resulting from gravitational effects. Measured (701, 702) antenna shape data in a target gravity loading environment and several test environments (600-603) are used to compute expected antenna beam misalignment angles in the test gravity loading environments (600-603). Actual antenna beam misalignment angles are measured (705) with the antenna (101) positioned in each of the test gravity loading environments (600-603). The expected antenna beam misalignment angles (704) are combined (707) with measured beam misalignment angles (705) to predict the beam misalignment of the antenna (101) in the target gravity loading environment. If the antenna (101) is an adjustable type, then the antenna (101) can be deliberately misaligned on the test range so that it will be properly aligned in the different gravity condition of the target environment. Further, thermal shape distortion data (706) can be incorporated to predict beam misalignment due to thermal distortion as well.

Method for measuring and correcting antenna RF beam alignment

A single microwave-reflective antenna 'dish' can be used in combination with a plurality of multiple-beam microwave feed arrays to generate or receive multiple-beam-path microwave radiation in several different frequency bands. Each of the feed arrays may operate in a discrete band of frequencies, with the combined radiations of all the arrays illuminating the reflector along a single axis. The optical system is based on the Newtonian model, such that the radiations from several arrays located off the principal axis may be combined by corresponding frequency-sensitive reflective surfaces located on the principal axis. Each of these reflective surfaces serves to direct the radiations from a single feed array toward the reflective antenna, and reciprocally, to direct radiation from the antenna to the associated feed array. By using frequency-sensitive surfaces as reflectors, a number of feed arrays can be positioned along the principal axis, the associated reflectors being reflective only at the frequency of the feed array concerned, and transparent at other frequencies.

Multiple frequency band, multiple beam microwave antenna system

This specification discloses a multibeam antenna which produces a null at one or more specified points with greater frequency band width for a given null depth. For example, a ring of beams about the null are set to have a phase difference between adjacent beams of 360.degree. divided by the number of beams in the ring. The amplitude of each of the beams is chosen so that each such ring set is self-nulled at the intended null and any common change in the side lobes of all beams of a ring set at the null due to frequency change is substantially equal. Thus, even with change in frequency, the null depth and position is substantially unchanged.

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Saratoga, CA, United States of America

William G Scott