Orthogonal linear transmit receive array radar

• US 8,248,298 B2
• Filed: 10/31/2009
• Issued: 08/21/2012
• Est. Priority Date: 10/31/2008
• Status: Active Grant

• Current Assignee: First RF Corporation
• Original Assignee: First RF Corporation
• Inventors: Lalezari, Farzin
• Primary Examiner(s): Keith, Jack W
• Assistant Examiner(s): BYTHROW, PETER M
• Application Number:
  US12/610,318
• Publication Number:
  US 20100141527A1
• Time in Patent Office: 1,025 Days
• Field of Search: 342/22, 342/118, 342/120, 342/179, 342/188, 343/730, 343/747, 343/757, 343/758, 343/763, 343/824, 343/830
• US Class Current: 342/179
• CPC Class Codes: H01Q 21/08 the units being spaced along or adjacent to a rectilinear path waveguide fed H01Q21/0037
• CPC Class Codes: H01Q 21/24 Combinations of antenna units polarised in different directions for transmitting or receiving circularly and elliptically polarised waves or waves linearly polarised in any direction circularly polarised patch antennas H01Q9/0428; circularly polarised horns H01Q13/0241; cross-polarised horns H01Q13/0258; polarisation converters H01Q15/242; cross-polarised rear feeds H01Q19/136; crossed polarisation dual antenna H01Q25/001

Abstract

A radar system having orthogonal antenna apertures is disclosed. The invention further relates to an antenna system wherein the orthogonal apertures comprise at least one transmit aperture and at least one receive aperture. The cross-product of the transmit and receive apertures provides a narrow spot beam and resulting high resolution image. An embodiment of the invention discloses orthogonal linear arrays, comprising at least one electronically scanned transmit linear array and at least one electronically scanned receive linear array. The design of this orthogonal linear array system produces comparable performance, clutter and sidelobe structure at a fraction of the cost of conventional 2D filled array antenna systems.

Claims

1. A radar system having an orthogonal antenna system, wherein said orthogonal antenna system comprises at least one transmit aperture producing a transmit beam and at least one receive aperture producing a receive beam, wherein said at least one transmit aperture is substantially orthogonal to said at least one receive aperture, wherein said transmit beam is narrow in a first dimension and wide in a second dimension, and said receive beam is wide orthogonally to said first dimension and narrow orthogonally to said second dimension, wherein a composite narrow beam cross-product results from an intersection of said transmit beam with said receive beam, and wherein said orthogonal antenna system, having a linear length of between 1.0 and 1.5 times that of a fully populated square 2D scan array, generates said composite narrow beam cross-product that is substantially the same resolution as said fully populated square 2D scan array.

2. The radar system according to claim 1, wherein said at least one transmit aperture and said at least one receive aperture are provided in a horn, pill box, planar, dielectric lens, dielectric rod, Cassegrain, parabolic, elliptical, circular dish or linear shape.

3. The radar system according to claim 1, wherein said orthogonal antenna system comprises at least one transmit aperture that rotates on a first one-axis gimbal and at least one receive aperture that rotates on a second one-axis gimbal in a plane orthogonal to said at least one transmit aperture.

4. The radar system according to claim 1, wherein said orthogonal antenna system comprises at least one transmit aperture that comprises at least one linear phased array and at least one receive aperture that comprises at least one linear phased array.

5. The radar system according to claim 4, wherein said at least one linear phased array transmit aperture and said at least one linear phased array receive aperture each further comprises a plurality of antenna elements disposed on an array face and connected by a combining network, and wherein each of said antenna elements further comprises a radiator and a phase shifter.

6. The radar system according to claim 5, wherein said at least one linear phased array transmit aperture and said at least one linear phased array receive aperture are scanned via mechanical scanning, electronic beam switching, electronically scanned phased array or digital beamforming.

7. The radar system according to claim 6, wherein said orthogonal antenna system provides high resolution imaging at a microwave frequency.

8. The radar system according to claim 6, wherein said orthogonal antenna system provides high resolution imaging at a millimeter wave frequency.

9. The radar system according to claim 1, wherein said at least one transmit aperture is switched to operate in a receive mode and said at least one receive aperture is simultaneously switched to operate in a transmit mode.

10. The radar system according to claim 9, wherein said at least one transmit aperture and said at least one receive aperture are provided in a horn, pill box, planar, dielectric lens, dielectric rod, Cassegrain, parabolic, elliptical, circular dish or linear shape.

11. The radar system according to claim 9, wherein said orthogonal antenna system comprises at least one transmit aperture that rotates on a first one-axis gimbal and at least one receive aperture that rotates on a second one-axis gimbal in a plane orthogonal to said at least one transmit aperture.

12. The radar system according to claim 9, wherein said orthogonal antenna system comprises at least one transmit aperture that comprises at least one linear phased array and at least one receive aperture that comprises at least one linear phased array.

13. The radar system according to claim 12, wherein said at least one linear phased array transmit aperture and said at least one linear phased array receive aperture each further comprises a plurality of antenna elements disposed on an array face and connected by a combining network, and wherein each of said antenna elements further comprises a radiator and a phase shifter.

14. The radar system according to claim 13, wherein said at least one linear phased array transmit aperture and said at least one linear phased array receive aperture are scanned via mechanical scanning, electronic beam switching, electronically scanned phased array or digital beamforming.

15. The radar system according to claim 14, wherein said orthogonal antenna system provides high resolution imaging at a microwave frequency.

16. The radar system according to claim 14, wherein said orthogonal antenna system provides high resolution imaging at a millimeter wave frequency.