Subwavelength Aperture Monopulse Conformal Antenna

• US 20080174509A1
• Filed: 12/27/2006
• Published: 07/24/2008
• Est. Priority Date: 12/27/2006
• Status: Active Grant

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Williams, Brett A.
• Granted Patent: US 8,354,953 B2
• Time in Patent Office: Days
• US Class Current: 343/872
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: F41G 7/2246 Active homing systems, i.e. comprising both a transmitter and a receiver
• CPC Class Codes: F41G 7/2253 Passive homing systems, i.e. comprising a receiver and do not requiring an active illumination of the target
• CPC Class Codes: F41G 7/226 Semi-active homing systems, i.e. comprising a receiver and involving auxiliary illuminating means, e.g. using auxiliary guiding missiles
• CPC Class Codes: F41G 7/2286 using radio waves
• CPC Class Codes: F41G 7/2293 using electromagnetic waves other than radio waves
• CPC Class Codes: G02B 5/008 Surface plasmon devices diffractive gratings with a pitch less than or comparable to the wavelength G02B5/1809; surface plasmons in integrated optics G02B6/1226; optical analysis of materials by means of surface plasmons G01N21/553
• CPC Class Codes: H01Q 1/281 Nose antennas
• CPC Class Codes: H01Q 1/42 Housings not intimately mechanically associated with radiating elements, e.g. radome
• CPC Class Codes: H01Q 15/0073 said selective devices having corrugations
• CPC Class Codes: H01Q 15/0086 said selective devices having materials with a synthesized negative refractive index, e.g. metamaterials or left-handed materials
• CPC Class Codes: H01Q 15/02 Refracting or diffracting devices, e.g. lens, prism

Abstract

In various aspects and embodiments, incident electromagnetic radiation is received through a subwavelength aperture in a lens, the subwavelength aperture being defined by a substrate encased in a dielectric medium.

Claims

1. A subwavelength electromagnetic wave receiver comprising:

a lens, including;

a dielectric medium;

a substrate encased in the dielectric medium and defining an subwavelength aperture; and

a detector receiving energy transmitted through the lens.

2. The apparatus of claim 1, wherein the dielectric medium comprises a solid material or a fluid material.

3. The apparatus of claim 1, wherein the dielectric medium comprises fused silica, Duroid, plastic, diamond, or air.

4. The apparatus of claim 1, wherein the substrate comprises a metal or a semiconducting material.

5. The apparatus of claim 1, wherein the aperture comprises an hourglass-shaped bore or a smooth bore.

6. The apparatus of claim 1, wherein the substrate includes a periodic surface feature functionally associated with the subwavelength aperture.

7. The apparatus of claim 6, wherein the periodic surface feature comprises a grating, a plurality of bumps, a plurality of posts, a plurality of divots, or a patch of roughness.

8. The apparatus of claim 6, wherein the periodic surface feature is a positive feature.

9. The apparatus of claim 6, wherein the periodic surface feature is a negative surface feature.

10. The apparatus of claim 1, wherein the detector comprises an optical detector or a radio frequency detector.

11. The apparatus of claim 1, further comprising a radome in which the lens is positioned.

12. An apparatus comprising:

a radome;

an evanescent wave-coupled lensing system in the radome, including an opposed pair of forward-looking lenses, each lens comprising;

a dielectric solid; and

a grating defining a subwavelength aperture, the grating being encased by the dielectric solid; and

a detector capable of receiving energy transmitted through the lensing system.

13. The apparatus of claim 12, wherein the missile radome comprises a metal or a dielectric material.

14. The method of claim 12, wherein the lenses are foreshortened.

15. The method of claim 12, wherein the dielectric solid comprises fused silica, Duroid, plastic, or diamond.

16. The method of claim 12, wherein the grating comprises concentric geometric grooves, linear grooves, or arcuate grooves.

17. The method of claim 12, wherein the grating comprises a metal or a semiconducting material.

18. The method of claim 12, wherein the aperture comprises an hourglass-shaped bore or a smooth bore.

19. The method of claim 12, wherein the detector comprises an optical detector or a radio frequency detector.

20. The apparatus of claim 12, wherein the radome is a sleek radome.

21. The apparatus of claim 12, wherein the sleek radome comprises a von Karman or an

22. The apparatus of claim 12, wherein the radome is a blunt radome.

23. The apparatus of claim 22, wherein the blunt radome comprises a semi-spherical or hemispherical radome.

24. The apparatus of claim 12, further comprising means for performing a non-coherent fresnel direction finding on the detected energy.

25. A radio frequency antenna, comprising:

a lensing system including a subwavelength aperture;

means for defining the geometry of the lensing system and in which the lensing system is disposed; and

a radio frequency detector capable of being evanescent-wave coupled to the lensing system and detecting a radio frequency signal received through the lensing system.

26. The radio frequency antenna of claim 25, wherein the determining means comprises a radome.

27. The radio frequency antenna of claim 25, wherein the lensing system comprises a plurality of lenses or a collar.

28. The radio frequency antenna of claim 25, wherein the lensing system comprises:

a substrate defining the subwavelength aperture; and

a dielectric medium encasing the substrate.

29. The radio frequency antenna of claim 28, wherein the substrate comprises a metal.

30. The radio frequency antenna of claim 29, wherein the metal substrate defines a periodic surface feature on at least one of the illumination side and the exit side thereof.

31. The radio frequency antenna of claim 28, wherein the substrate comprises a semiconducting material.

32. The radio frequency antenna of claim 28, wherein the dielectric medium comprises at least one of a composite material, a plastic, fused silica, diamond, and air.

33. The radio frequency antenna of claim 28, wherein the substrate defines a plurality of subwavelength apertures.

34. The radio frequency antenna of claim 25, wherein the lensing system defines a plurality of subwavelength apertures.

35. The radio frequency antenna of claim 25, wherein the metal substrate comprises a grating.

36. The radio frequency antenna of claim 25, wherein the cross-section of the aperture is an hourglass cross-section.

37. The radio frequency antenna of claim 25, wherein the metallic substrate defines a plurality of subwavelength apertures.

38. An apparatus, comprising:

a metal substrate defining a subwavelength aperture therein; and

a dielectric solid encasing the metal substrate.

39. The apparatus of claim 38, wherein the cross-section of the aperture is an hourglass cross-section.

40. The apparatus of claim 38, wherein the metal substrate comprises a grating.

41. The apparatus of claim 40, wherein the grating includes concentric circular grooves enclosing the aperture.

42. The apparatus of claim 40, wherein the grating includes rectangular grooves.

43. A method, comprising:

receiving energy through a pair of opposing subwavelength apertures; and

determining a target angle from the steep change of amplitude versus angle presented by the aperture'"'"'s beamwidth.

44. The method of claim 43, wherein the received energy is optical frequency energy.

45. The method of claim 43, wherein the receive energy is radio frequency energy.

46. A lens, comprising:

a substrate defining a subwavelength aperture therethrough and a periodic surface feature thereon; and

a dielectric medium encasing the substrate.

47. An apparatus comprising:

a sleek missile radome;

a lensing system in the missile radome, including an opposed pair of forward-looking lenses, each lens comprising;

a dielectric solid; and

a grating defining a subwavelength aperture, the grating being encased by the dielectric solid, the dielectric solid filling the aperture; and

a detector capable of receiving energy transmitted through the lensing system.

48. The apparatus of claim 47, wherein the missile radome comprises a metal or a dielectric material.

49. The apparatus of claim 47, wherein the sleek radome comprises a von Karman or an Ogive radome.

50. The apparatus of claim 47, wherein the lenses are foreshortened.

51. The apparatus of claim 47, wherein the dielectric solid comprises fused silica, Duroid, plastic, or diamond.

52. The apparatus of claim 47, wherein the grating comprises concentric geometric grooves, linear grooves, or arcuate grooves.

53. The apparatus of claim 47, wherein the grating comprises a metal or a semiconducting material.

54. The apparatus of claim 47, wherein the aperture comprises an hourglass-shaped bore or a smooth bore.

55. The apparatus of claim 47, wherein the detector comprises an optical detector or a radio frequency detector.

56. A method, comprising:

receiving an optical frequency signal through a foreshortened lens to which a non-reflective coating has been applied; and

determining target angle from the received optical frequency signal.

57. A method, comprising:

receiving a returned radio frequency signal through a subwavelength aperture defined in a metal substrate underlying a least a portion of a dielectric medium; and

detecting the received signal.

58. An apparatus comprising:

an opposing pair of antennas, separated by a predetermined distance, each antenna including;

a dielectric medium;

a metal substrate defining subwavelength aperture, the grating being encased by the dielectric medium, the dielectric medium filling the aperture; and

a detector capable of receiving energy transmitted through the aperture.

59. The apparatus of claim 58, wherein the dielectric medium is a solid.

60. The apparatus of claim 58, wherein the metal substrate comprises a grating.

61. A missile, comprising:

a sleek radome;

a lensing system, including a pair of lenses, each lens comprising;

a dielectric medium; and

a substrate encased in the dielectric medium and defining a subwavelength aperture therethrough and a periodic surface feature thereon;

a pair of detectors, each detector capable of receiving energy transmitted through the lens;

a flight control mechanism; and

a controller capable of non-coherent Fresnel direction finding a target from the received energy and transmitting a flight correction signal to the flight control mechanism responsive thereto.