Patch antenna with an electrically small ground plate using peripheral parasitic stubs

• US 6,181,279 B1
• Filed: 05/08/1998
• Issued: 01/30/2001
• Est. Priority Date: 05/08/1998
• Status: Expired due to Term

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: Northrop Grumman Corporation
• Inventors: Van Hoozen, Allen Lee
• Primary Examiner(s): Wong, Don
• Assistant Examiner(s): VANNUCCI, JAMES
• Application Number:
  US09/075,091
• Time in Patent Office: 998 Days
• Field of Search: 343/700.MS, 343/767
• US Class Current: 343/700.0MS
• CPC Class Codes: H01Q 1/52 Means for reducing coupling between antennas; Means for reducing coupling between an antenna and another structure absorbing means H01Q17/00
• CPC Class Codes: H01Q 9/0407 Substantially flat resonant element parallel to ground plane, e.g. patch antenna dipole H01Q9/285; monopole H01Q9/40
• CPC Class Codes: H01Q 9/0428 radiating a circular polarised wave
• CPC Class Codes: H01Q 9/0435 using two feed points
• CPC Class Codes: H01Q 9/0442 with particular tuning means
• CPC Class Codes: H01Q 9/0478 with means for suppressing spurious modes, e.g. cross polarisation

Abstract

In accordance with the present invention, there is provided a patch antenna assembly having a generally planar patch antenna, defined by a first peripheral boundary, and a generally planar parasitic ground plate, disposed to spaced parallel relation to the patch antenna. The assembly further includes at least one conductive parasitic shielding element for segregating electromagnetic fields between the patch antenna and the ground plate. The shielding element is disposed in electrical communication with the ground plate and extends from the ground plate and substantially about the first peripheral boundary of the patch antenna.

Claims

1. A patch antenna assembly comprising:

a generally planar patch antenna element defining a first peripheral boundary;

a generally planar ground plate disposed parallel to the patch element, the patch element aligned off-center from the ground plate; and

a radiation and impedance pattern shaping shielding element connected to and extending from the ground plate and surrounding the patch element, while being electrically isolated from the patch element.

2. The antenna assembly of claim 1 wherein the shielding element comprises a plurality of vias for segregating electro-magnetic fields between the patch antenna and the ground plate.

3. The antenna assembly of claim 2 wherein the vias being elongated and cylindrical in shape.

4. The antenna assembly of claim 2 wherein the antenna being sized and configured for a particular electro-magnetic wavelength and respective ones of the plurality vias being spaced approximately one twenty-fifth wavelength apart.

5. The antenna assembly of claim 1 wherein the antenna being sized and configured for a particular electro-magnetic wavelength and the antenna and the ground plate being spaced approximately one twenty-fifth wavelength apart.

6. The antenna assembly of claim 5 further comprising a dielectric material interposed between the antenna and the ground plate, the dielectric material having a dielectric constant of four.

7. The antenna assembly of claim 1 wherein the shielding element having a height extending from the ground plate approximately equal to the spacing between the patch antenna and the ground plate.

8. The patch antenna assembly of claim 1 wherein the patch antenna having a rectangular geometry.

9. The patch antenna assembly of claim 8 wherein the patch antenna having first length and a first width and the ground plate having a second length and a second width, the second length being approximately twice the first length and the second width being approximately twice the first width.

10. The patch antenna assembly of claim 8 wherein the patch antenna having first length and a first width and the ground plate having a second length and a second width, the second length being less than twice the first length and the second width being less than twice the first width.

11. The patch antenna assembly of claim 1 wherein the patch antenna having a first surface area and the ground plate having a second surface area, the second surface area being approximately four times the first surface area.

12. The patch antenna assembly of claim 1 wherein the ground plate defining a second peripheral boundary larger than the first peripheral boundary of the patch antenna.

13. The patch antenna assembly of claim 1 wherein the patch antenna being a linearly polarized antenna.

14. The patch antenna assembly of claim 1 wherein the patch antenna being a circularly polarized antenna.

15. The patch antenna assembly of claim 1 wherein the patch antenna having a circular geometry.

16. The antenna assembly of claim 1 wherein the patch antenna and the ground plate being formed on a dielectric substrate.

17. The antenna assembly of claim 1 wherein the patch antenna and the ground plate being formed of a metallic material.

18. The antenna assembly of claim 17 wherein the shielding element being formed of a metallic material.

19. The antenna assembly of claim 1 further comprising a generally planar signal generating layer for generating a transmission signal, the signal generating layer having signal generating circuitry in electrical communication with the patch antenna.

20. The antenna assembly of claim 19 wherein the shielding element extends from the ground plate to the signal generating layer for shielding the signal generating circuitry from external signals.

21. The antenna assembly of claim 19 further comprising a via extending from the signal generating circuitry and through the ground plate and terminating at the patch antenna for facilitating electrical communication between the signal generating circuitry and the patch antenna.

22. The antenna assembly of claim 1 further comprising a generally planar signal processing layer for processing a signal received with the patch antenna, the signal processing layer having signal processing circuitry in electrical communication with the patch antenna.

23. The antenna assembly of claim 22 wherein the shielding element extends from the ground plate to the signal processing layer for shielding the signal processing circuitry from external signals.

24. The antenna assembly of claim 22 further comprising a via extending from the signal processing circuitry and through the ground plate and terminating at the patch antenna for facilitating electrical communication between the signal processing circuitry and the patch antenna.

25. A patch antenna assembly comprising:

a generally planar patch antenna element defining a first peripheral boundary;

a generally planar ground plate disposed parallel to the patch element, the patch element being aligned off-center from the ground plate; and

at least one radiation and impedance pattern shaping shielding element connected to and extending from the ground plate and surrounding the patch element, while being electrically isolated from the patch element.

26. A patch antenna array comprising a plurality of patch antenna assemblies, each of the patch antenna assemblies comprising:

a generally planar patch antenna element defining a first peripheral boundary;

a generally planar ground plate disposed parallel to the patch element, the patch element being aligned off-center from the ground plate; and

at least one radiation and impedance pattern shaping shielding element connected to and extending from the ground plate and surrounding the patch element, while being electrically isolated from the patch element.

27. A method of making a patch antenna assembly comprising the steps of:

(a) providing a generally planar dielectric substrate having first and second sides;

(b) affixing a conductive material to the first and second sides of the dielectric substrate;

(c) removing a portion of the conductive material from the first side so as to form a patch antenna from the remaining conductive material which is defined by a first peripheral boundary;

(d) drilling a plurality of holes through the dielectric substrate about the first peripheral boundary of the patch antenna; and

(e) forming an electrical connection with the conductive material of the second side but not the first side by filling the holes with a conductive material.

28. The method of claim 27 wherein step (b) comprises affixing the conductive material using a metal plating process.

29. The method of claim 27 wherein step (c) comprises removing a portion of the conductive material using an etching process.

30. The method of claim 27 wherein step (c) further comprises removing a portion of the conductive material from the first side of the dielectric substrate to form a plurality of discs having a first diameter from the remaining conductive material and step (d) further comprises drilling a plurality of holes through the discs and the dielectric substrate, the holes having a second diameter less than the first diameter of the discs.

31. The method of claim 30 wherein step (e) comprises filling the holes so as to electrically connect the discs to the conductive material on the second side of the dielectric substrate.

32. The method of claim 27 wherein step (e) comprises filling the holes using a metal plating process.

33. A patch antenna assembly comprising:

a generally planar patch antenna defining a first peripheral boundary;

a generally planar parasitic ground plate disposed parallel to the patch antenna and in spaced relation thereto;

a conductive parasitic shielding element for segregating electromagnetic fields between the patch antenna and the ground plate, the shielding element being in electrical communication with the ground plate, extending from the ground plate, and disposed substantially about the first peripheral boundary of the patch antenna;

a generally planar signal generating layer for generating a transmission signal, the signal generating layer having signal generating circuitry in electrical communication with the patch antenna in spaced relation to the first peripheral boundary and electrically isolated therefrom; and

a via extending from the signal generating circuitry and through the ground plate and terminating at the patch antenna for facilitating electrical communication between the signal generating circuitry and the patch antenna.

34. The antenna assembly of claim 33 wherein the shielding element comprises a plurality of vias for segregating electro-magnetic fields between the patch antenna and the ground plate.

35. The antenna assembly of claim 34 wherein the vias being elongated and cylindrical in shape.

36. The antenna assembly of claim 34 wherein the antenna being sized and configured for a particular electro-magnetic wavelength and respective ones of the plurality vias being spaced approximately one twenty-fifth wavelength apart.

37. The antenna assembly of claim 33 wherein the antenna being sized and configured for a particular electro-magnetic wavelength and the antenna and the ground plate being spaced approximately one twenty-fifth wavelength apart.

38. The antenna assembly of claim 37 further comprising a dielectric material interposed between the antenna and the ground plate, the dielectric material having a dielectric constant of four.

39. The antenna assembly of claim 33 wherein the shielding element having a height extending from the ground plate approximately equal to the spacing between the patch antenna and the ground plate.

40. The antenna assembly of claim 33 wherein the patch antenna having a rectangular geometry.

41. The antenna assembly of claim 40 wherein the patch antenna having first length and a first width and the ground plate having a second length and a second width, the second length being approximately twice the first length and the second width being approximately twice the first width.

42. The antenna assembly of claim 40 wherein the patch antenna having first length and a first width and the ground plate having a second length and a second width, the second length being less than twice the first length and the second width being less than twice the first width.

43. The antenna assembly of claim 33 wherein the patch antenna having a first surface area and the ground plate having a second surface area, the second surface area being approximately four times the first surface area.

44. The antenna assembly of claim 33 wherein the ground plate defining a second peripheral boundary larger than the first peripheral boundary of the patch antenna.

45. The antenna assembly of claim 33 wherein the patch antenna being a linearly polarized antenna.

46. The antenna assembly of claim 33 wherein the patch antenna being a circularly polarized antenna.

47. The antenna assembly of claim 33 wherein the patch antenna having a circular geometry.

48. The antenna assembly of claim 33 wherein the patch antenna and the ground plate being formed on a dielectric substrate.

49. The antenna assembly of claim 33 wherein the patch antenna and the ground plate being formed of a metallic material.

50. The antenna assembly of claim 49 wherein the shielding element being formed of a metallic material.

51. The antenna assembly of claim 33 wherein the patch antenna being aligned off-center with respect to the ground plate.

52. The antenna assembly of claim 33 wherein the shielding element extends from the ground plate to the signal generating layer for shielding the signal generating circuitry from external signals.

53. The antenna assembly of claim 33 further comprising a generally planar signal processing layer for processing a signal received with the patch antenna, the signal processing layer having signal processing circuitry in electrical communication with the patch antenna.

54. The antenna assembly of claim 53 wherein the shielding element extends from the ground plate to the signal processing layer for shielding the signal processing circuitry from external signals.

55. The antenna assembly of claim 53 further comprising a via extending from the signal processing circuitry and through the ground plate and terminating at the patch antenna for facilitating electrical communication between the signal processing circuitry and the patch antenna.

56. A patch antenna assembly comprising:

a generally planar patch antenna defining a first peripheral boundary;

a generally planar parasitic ground plate disposed parallel to the patch antenna and in spaced relation thereto;

at least one conductive parasitic shielding element for segregating electro-magnetic fields between the patch antenna and the ground plate, the shielding element being in electrical communication with the ground plate, extending from the ground plate, and disposed exterior to the first peripheral boundary of the patch antenna in spaced relation to the first peripheral boundary and electrically isolated therefrom;

a generally planar signal generating layer for generating a transmission signal, the signal generating layer having signal generating circuitry in electrical communication with the patch antenna; and

a via extending from the signal generating circuitry and through the ground plate and terminating at the patch antenna for facilitating electrical communication between the signal generating circuitry and the patch antenna.

57. A patch antenna array comprising a plurality of patch antenna assemblies, each of the patch antenna assemblies comprising:

a generally planar patch antenna defining a first peripheral boundary;

a generally planar parasitic ground plate disposed parallel to the patch antenna and in spaced relation thereto;

at least one conductive parasitic shielding element for segregating electro-magnetic fields between the patch antenna and the ground plate, the shielding element being in electrical communication with the ground plate, extending from the ground plate, and disposed exterior to the first peripheral boundary of the patch antenna in spaced relation to the first peripheral boundary and electrically isolated therefrom;

a generally planar signal generating layer for generating a transmission signal, the signal generating layer having signal generating circuitry in electrical communication with the patch antenna; and

a via extending from the signal generating circuitry and through the ground plate and terminating at the patch antenna for facilitating electrical communication between the signal generating circuitry and the patch antenna.

58. A patch antenna assembly comprising:

a generally planar patch antenna element;

a generally planar ground plate disposed parallel to the patch element, the patch element being aligned off center from the ground plate;

a shielding element connected to and extending from the ground plate and surrounding the patch element, while being electrically isolated from the patch element;

a generally planar signal generating layer with circuitry connected to the patch element; and

a via extending from the signal generating circuitry through the ground plate to the patch element.

59. The antenna assembly of claim 58 wherein the shielding element comprises a plurality of vias for segregating electro-magnetic fields between the patch element and the ground plate.

60. The antenna assembly of claim 59 wherein the vias being elongated and cylindrical in shape.

61. The antenna assembly of claim 59 wherein the patch element being sized and configured for a particular electromagnetic wavelength and respective ones of the plurality vias being spaced approximately one twenty-fifth wavelength apart.

62. The antenna assembly of claim 58 wherein the patch element being sized and configured for a particular electromagnetic wavelength and the patch element and the ground plate being spaced approximately one twenty-fifth wavelength apart.

63. The antenna assembly of claim 62 further comprising a dielectric material interposed between the patch element and the ground plate, the dielectric material having a dielectric constant of four.

64. The antenna assembly of claim 58 wherein the shielding element having a height extending from the ground plate approximately equal to the spacing between the patch element and the ground plate.

65. The antenna assembly of claim 58 wherein the patch element having a rectangular geometry.

66. The antenna assembly of claim 65 wherein the patch element having first length and a first width and the ground plate having a second length and a second width, the second length being approximately twice the first length and the second width being approximately twice the first width.

67. The antenna assembly of claim 65 wherein the patch element having first length and a first width and the ground plate having a second length and a second width, the second length being less than twice the first length and the second width being less than twice the first width.

68. The antenna assembly of claim 58 wherein the patch element having a first surface area and the ground plate having a second surface area, the second surface area being approximately four times the first surface area.

69. The antenna assembly of claim 58 wherein the ground plate defining a second peripheral boundary larger than the first peripheral boundary fo the patch element.

70. The antenna assembly of claim 58 wherein the patch element being a linearly polarized antenna.

71. The antenna assembly of claim 58 wherein the patch element having a circular geometry.

72. The antenna assembly of claim 58 wherein the patch element and the ground plate being formed ona dielectric substrate.

73. The antenna assembly of claim 58 wherein the patch element and the ground plate being formed of a metallic material.

74. The antenna assembly of claim 73 wherein the shielding element being formed of a metallic material.

75. The antenna assembly of claim 58 wherein the shielding element extends from the ground plate to the signal generating layer for shielding the signal generating circuitry from external signals.

76. The antenna assembly of claim 58 further comprising a generally planar signal processing layer for processing a signal received with the patch element, the signal processing layer having signal processing circuitry in electrical communication with the patch element.

77. The antenna assembly of claim 76 wherein the shielding element extends from the ground plate to the signal processing layer for shielding the signal processing circuitry from external signals.

78. The antenna assembly of claim 76 further comprising a via extending from the signal processing circuitry and through the ground plate and terminating at the patch element for facilitating electrical communication between the signal processing circuitry and the patch element.

79. A patch antenna assembly comprising:

a generally planar patch antenna element;

a generally planar ground plate disposed parallel to the patch element, the patch element being aligned off center from the ground plate;

at least one shielding element connected to and extending from the ground plate and surrounding the patch element, while being electrically isolated from the patch element;

a generally planar signal generating layer with circuitry connected to the patch element; and

a via extending from the signal generating circuitry through the ground plate to the patch element.

80. A patch antenna array comprising a plurality of patch antenna assemblies, each of the patch antenna assemblies comprising:

a generally planar patch antenna element;

a generally planar ground plate disposed parallel to the patch element, the patch element being aligned off center from the ground plate;

a shielding element connected to and extending from the ground plate and surrounding the patch element, while being electrically isolated from the patch element;

at least one generally planar signal generating layer with circuitry connected to the patch element; and

a via extending from the signal generating circuitry through the ground plate to the patch element.