Antenna having a plurality of resonant frequencies

• US 20080211725A1
• Filed: 05/05/2008
• Published: 09/04/2008
• Est. Priority Date: 04/15/2005
• Status: Active Grant

• Current Assignee: Nokia Corporation
• Original Assignee: Nokia Corporation
• Inventors: Ollikainen, Jani
• Granted Patent: US 7,705,791 B2
• Time in Patent Office: Days
• US Class Current: 343/749
• CPC Class Codes: H01Q 1/243 with built-in antennas
• CPC Class Codes: H01Q 1/38 formed by a conductive layer on an insulating support patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142
• CPC Class Codes: H01Q 9/26 with folded element or elements, the folded parts being spaced apart a small fraction of operating wavelength resonant loop antennas H01Q7/00
• CPC Class Codes: H01Q 9/265 Open ring dipoles; Circular dipoles

Abstract

An antenna having a plurality of resonant frequencies and including a ground plane having an edge; a feed point; a ground point; and

• • an antenna track extending between the feed point and the ground point and comprising, in series connection, a first loop and a second loop wherein a least a portion of the first loop and a portion of the second loop are adjacent at least the edge of the ground plane.

Claims

1-43. -43. (canceled)

44. An antenna having a plurality of resonant frequencies and comprising:

a ground plane;

a feed point;

a ground point; and

an antenna track extending between the feed point and the ground point and comprising, in series connection, a first loop and a second loop and having a first continuous band of operation and a second continuous band of operation,

wherein the first continuous band of operation corresponds to a fundamental resonant frequency of the antenna, and the second continuous band of operation corresponds to the second and third harmonic resonances of the fundamental resonant frequency of the antenna, wherein the third harmonic is tuned, using reactive loading, towards the second harmonic.

45. The antenna as claimed in claim 44, wherein the antenna is shaped and arranged so that the fundamental resonant frequency and the second and third harmonic resonances couple to one or more resonances of the ground plane.

50. The antenna as claimed in claim 44, wherein the first continuous band of operation covers the GSM 850 band and/or GSM900 band and the second continuous band of operation covers the GSM 1800 band and/or GSM1900 band.

51. The antenna as claimed in claim 44, wherein the antenna track has a length L, and the reactive loading comprises a first inductive load located at a position where the electrical current associated with the third harmonic is greater than the electric current associated with the second harmonic.

52. The antenna as claimed in claim 44, wherein the antenna track has a length L, and the reactive loading comprises a first inductive load located at a position between L/5 and 2L/5 from the ground point and a second inductive load located at a position between 3L/5 and 4L/5 from the ground point.

53. The antenna as claimed in claim 44, wherein the reactive loading comprises a plurality of bends in the antenna track.

54. The antenna as claimed in claim 44, wherein the antenna track has a length L, and the reactive loading comprises one or more capacitive loads positioned where the electrical field associated with the third harmonic is greater than the electric field associated with the second harmonic.

55. The antenna as claimed in claim 44, wherein the antenna track has a length L, and the reactive loading comprises at least one capacitive load located substantially at a position between 2L/5 and 3L/5 from the ground point.

56. The antenna as claimed in claim 55, wherein a capacitive load is located at a position L/2 from the ground point.

57. The antenna as claimed in claim 44, wherein the antenna track has a length L, and the reactive loading comprises a first capacitive load positioned between L/5 and L/4 from the ground point and a second capacitive load positioned between 3L/4 and 4L/5 from the ground point.

58. The antenna as claimed in claim 57, wherein the first capacitive load is located at a first return bend of the first loop and the second capacitive load is located at a second return bend of the second loop.

59. The antenna as claimed in claim 44, wherein the antenna track has a length L, and is without bends where the electrical current associated with the second harmonic is significantly greater than the electric current associated with the third harmonic.

60. The antenna as claimed in claim 44, wherein the antenna track has a length L, and is without bends within the region between 2L/5 and 3L/5 from the ground point.

61. The antenna as claimed in claim 44, wherein the antenna track has a length L, and is without bends around L/2 from the ground point.

62. An apparatus comprising the antenna as claimed in claim 44.

46. An antenna having a plurality of resonant frequencies and comprising:

a ground plane having an edge;

an antenna track comprising an edge wherein at least a portion of the antenna edge is adjacent to the ground plane edge; and

reactive loading of the antenna track.

47. The antenna as claimed in claim 46, wherein the antenna has a first continuous band of operation and a second continuous band of operation, wherein the first continuous band of operation corresponds to the combination of a fundamental resonant frequency (first harmonic resonance) of the antenna and at least one resonant frequency of the ground plane, and the second continuous band of operation corresponds to the combination of the second and third harmonic resonances of the fundamental resonance of the antenna and at least one resonant frequency of the ground plane, wherein the third harmonic is tuned, by the reactive loading, towards the second harmonic.

48. The antenna as claimed in claim 46, wherein the antenna track is U-shaped.

49. The antenna as claimed in claim 46, wherein at least one reactive load is electrically controlled.

65. The apparatus comprising the antenna as claimed in claim 46.

63. A method comprising:

providing an antenna having a plurality of resonant frequencies and including;

a ground plane;

a feed point;

a ground point; and

an antenna track extending between the feed point and the ground point and comprising, in series connection, a first loop and a second loop and having a first continuous band of operation and a second continuous band of operation, wherein the first continuous band of operation corresponds to a fundamental resonant frequency of the antenna, and the second continuous band of operation corresponds to the second and third harmonic resonances of the fundamental resonant frequency of the antenna,

tuning the third harmonic, using reactive loading, towards the second harmonic.

64. The method as claimed in claim 63, further comprising arranging the antenna so that the fundamental resonant frequency and the second and third harmonic resonances couple to one or more resonances of the ground plane.

66. A method comprising:

providing an antenna having a plurality of resonant frequencies and including;

a ground plane having an edge, an antenna track comprising an edge, and reactive loading of the antenna track; and

arranging at least a portion of the antenna edge adjacent the ground plane edge.

67. A method as claimed in claim 66, wherein the antenna has a first continuous band of operation and a second continuous band of operation, wherein the first continuous band of operation corresponds to the combination of a fundamental resonant frequency (first harmonic resonance) of the antenna and at least one resonant frequency of the ground plane, and the second continuous band of operation corresponds to the combination of the second and third harmonic resonances of the fundamental resonance of the antenna and at least one resonant frequency of the ground plane;

further comprising tuning the third harmonic, using the reactive loading, towards the second harmonic.