James Howell

US Patent:

47207124, Jan 19, 1988

Filed:

Aug 12, 1985

Appl. No.:

6/764803

Inventors:

Eli Brookner - Lexington MA
James M. Howell - Hudson MA

Assignee:

Raytheon Company - Lexington MA

International Classification:

G01S 316
G01S 328

US Classification:

342383

Abstract:

A beam forming apparatus is provided having a plurality of beam ports producing a corresponding plurality of differently directed beams, each one of such beams being associated with a corresponding one of the beam ports, one of such beams being directed at a desired signal source and at least one of the beams being directed at an interfering signal source. A processor is coupled to the beam ports, for combining signals at such beam ports into a composite signal with the ratio of the power of the desired signal component of such composite signal to the power of the interfering signal component of such composite signal being increased from the ratio of the power in such desired and interfering signal components at the one of the beam ports associated with the beam directed at the desired signal source. The beam forming apparatus directs one of the beams at a desired signal source and an additional beam at each one of a number of interfering signal sources. The signals within the additional beams are weighted and then subtracted from the signals in the desired signal directed beam to substantially cancel the interfering signals from the desired signal.

US Patent:

48137669, Mar 21, 1989

Filed:

Mar 2, 1988

Appl. No.:

7/162992

Inventors:

Wayne H. Keene - South Natick MA
Terry A. Dorschner - Newton Centre MA
James M. Howell - Hudson MA

Assignee:

Raytheon Company - Lexington MA

International Classification:

G02F 113

US Classification:

350337

Abstract:

An optical time delay unit for use in an optical phased array beam-steering system includes a switchable polarization rotator in conjunction with Brewster plates and mirrors to form electrically-selectable optical paths of different lengths. The switchable polarization rotator is aligned with the optical beam and is responsive to a control signal for varying the polarization of light passing therethrough. The Brewster plates receive the light passing through the first polarization rotator and are transmissive to a first polarization and reflective of a second. The transmissive and reflective paths are of different lengths, and are recombined at a second Brewster plate. The original polarization may be restored by a second polarization rotator. A plurality of time delay units may be cascaded to permit selection from among many paths of various lengths. In a preferred embodiment, the polarization rotators include liquid crystal cells having nematic phase molecules.