Microwave radiating element and antenna array including linear phase shift progression angular tilt
AssigneeTull Aviation Corporation
InventorDonald J. Toman
Life of this patent
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Abstract
A slotted waveguide radiator for an antenna array is arranged to receive microwave energy inputs at either end for producing separate radiated beams and has loading slots having predetermined center-to-center spacings in the longitudinal dimension to provide a predetermined squint angle for each radiated beam which is related to the direction in which energy is fed to the waveguide. The radiator includes means for providing a linear phase shift progression in the signal components radiated from the slots from one end of the waveguide to the other to thereby provide an angular tilt to each radiated beam which is independent of the direction in which energy is fed to the waveguide.
Claims23
A line source microwave radiation element for feeding a reflector for radiating two shaped beams at selected angles comprising
- a slotted waveguide arranged to receive signal inputs at either end and having loading slots arranged in the face of one wall thereof and spaced transversely with respect to the longitudinal axial center line thereof to produce beams of a desired shape within a central plane containing said axial center line,
- said loading slots having predetermined center-to-center spacings in the longitudinal dimension to provide a predetermined squint angle within said central plane for each radiated beam with respect to the plane of said slotted face and related to the direction in which energy is fed to the waveguide,
- and means for providing a linear phase shift progression in the signal components radiated from the slots from one end of said waveguide to the other to thereby provide a predetermined angular tilt to each radiated beam within said central plane which is independent of the direction in which energy is fed to the waveguide and which is algebraically added to said squint angle.
An antenna array for feeding a reflector for radiating a pattern of angularly spaced microwave radio beams which are particularly useful for instrument guidance of aircraft comprising
- a first pair of slotted waveguide microwave signal radiating elements,
- each of said elements having loading slots in the face of one wall thereof and spaced transversely with respect to the longitudinal axial center line thereof to produce beams of a desired shape within a central plane containing said axial center line,
- said antenna array being operable as a switched scanning beam antenna array in which carrier energy is switched in a sequence from one beam to another,
- said radiating elements each including means for separately introducing signals at each end thereof,
- each of said radiating elements being designed with the positions of the slots in the slotted wall thereof arranged so as to provide radiation directed outwardly at predetermined angles referred to as squint angles of deviation away from a direction normal to the slotted face of the radiating element,
- said squint angles being dependent upon the direction of propagation of the signal through the waveguide so that oppositely disposed squint angles are provided when the radiation element is fed from opposite ends,
- said radiating elements being arranged end to end with the radiation apertures formed by said radiating elements being in mutual alignment and being mutually parallel so that the central plane of the individual beams produced by each of said radiating elements is a common central plane,
- said radiating elements of said first pair having equal squint angles,
- each of said radiating elements of said first pair including means for providing a linear phase shift progression in the signal components radiated from the slots from one end of said element to the other to thereby provide a predetermined angular tilt to each beam within said central plane which is independent of the direction in which energy is fed to the element and which is algebraically added to the applicable squint angle,
- the phase shift progression angular tilt for one of said radiating elements of said first pair being opposite to the phase shift progression angular tilt for the other one of said radiating elements of said first pair and the combinations of squint angles and phase shift progression angular tilts being selected to provide four beams from said radiating elements which are at four different selected angles within said central plane.
A method of radiating two shaped beams of microwave energy to a reflector from a single slotted waveguide at different selected angles in relation to a direction normal to the waveguide comprising the steps of
- positioning the loading slots in the slotted face of the waveguide with predetermined center-to-center spacings in the longitudinal dimension to provide a predetermined squint angle for the radiated beams related to the direction in which energy is fed to the waveguide,
- providing a linear phase shift progression in the signal components radiated from the slots from one end of the waveguide to the other to thereby provide a predetermined angular tilt to each radiated beam which is independent of the direction in which energy is fed to the waveguide,
- and then introducing microwave energy to the opposite ends of the waveguide in sequence to provide separately directed beams in response to the energy introduced to the respective ends of the waveguide.
Dependencies are inferred from the claim text.