Phased array antenna system using polarization phase shifting
First Claim
1. A phased array antenna system for receiving or transmitting external circularly polarized radiation having a predetermined polarization sense, comprising:
- a plurality of radiating elements mounted in respective rows and columns to thereby form a two dimension array, each radiating element in the array containing at least two perpendicular sets of two radially disposed opposing segments;
beamforming means for combining or deriving four mode signals respectively associated with four phase quadrature components of said external circularly polarized radiation into or from a single internal signal representative of said circularly polarized radiation; and
switching means responsive to an external beam steering control signal and having at least four radiating element terminals respectively coupled to the segments of each of said radiating elements, for selecting which of said segments of the same radiating element will function as each of four arms of a respective crossed dipole antenna and for coupling the selected segments associated with each said arm of the same crossed dipole antenna to a different selected one of said four mode signals, to thereby determine a relative polarization phase of said same radiating element relative to the other radiating elements in the array.
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Accused Products
Abstract
A circularly polarized phased array antenna system for both reception and transmission applications includes a plurality of planar radiating (or receiving) elements, a switching matrix for each radiating element, a beamforming network and a transmit/receive module. Each planar element includes 4×N radially disposed segments that may be selectively connected with the four modes of a circularly polarized signal such that two opposing segments function as the two respective arms of a dipole radiating element and two orthogonal such dipoles function as a crossed pair of dipoles for receiving or transmitting the circularly polarized signal. The switching matrix and the beamforming network cooperate to determine the polarization phase of the radiating element by commutating the four modes of the circularly polarized signal to any four orthogonal segments of the radiating element. The polarization sense may be changed between right-hand and left-hand circular either within the bandforming network, or by causing the switching network to reverse the two signal modes connected across one of the dipoles. If N is greater than 1, then by electrically connecting up to N-1 nearby segments to thereby increase the effective angle subtended by each arm, the bandwidth may be increased while still permitting the radiating element'"'"'s polarization phase to be determined in increments equal to the angle subtended by one segment; by selectively using either an odd or even number of segments to define the effective angle subtended by each dipole arm, the relative phase of that element may be determined in increments equal to half the angle subtended by one segment.
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Citations
20 Claims
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1. A phased array antenna system for receiving or transmitting external circularly polarized radiation having a predetermined polarization sense, comprising:
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a plurality of radiating elements mounted in respective rows and columns to thereby form a two dimension array, each radiating element in the array containing at least two perpendicular sets of two radially disposed opposing segments; beamforming means for combining or deriving four mode signals respectively associated with four phase quadrature components of said external circularly polarized radiation into or from a single internal signal representative of said circularly polarized radiation; and switching means responsive to an external beam steering control signal and having at least four radiating element terminals respectively coupled to the segments of each of said radiating elements, for selecting which of said segments of the same radiating element will function as each of four arms of a respective crossed dipole antenna and for coupling the selected segments associated with each said arm of the same crossed dipole antenna to a different selected one of said four mode signals, to thereby determine a relative polarization phase of said same radiating element relative to the other radiating elements in the array. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method for antenna beam steering for a phased array of circularly polarized radiating elements, comprising the steps of:
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associating each set of four mutually perpendicular radial segments of a designated radiating element with a respective pair of crossed dipoles; selecting a segment of one of said pairs of crossed dipoles having an angular orientation corresponding to a desired relative polarization phase for said designated radiating element; and commutating four mode signals defining radiation having a predetermined polarization to the pair of said crossed dipoles including the selected segment, with a predetermined said mode signal coupled to said selected segment and the other three mode signals being coupled to the other three segments. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification