Antenna assembly, and associated method, having an active antenna element and counter antenna element

• US 6,480,155 B1
• Filed: 12/28/1999
• Issued: 11/12/2002
• Est. Priority Date: 12/28/1999
• Status: Expired due to Fees

• Current Assignee: Nokia Technologies Oy (Nokia Corporation)
• Original Assignee: Nokia Corporation
• Inventors: Eggleston, Steve
• Primary Examiner(s): Wong, Don
• Assistant Examiner(s): VANNUCCI, JAMES
• Application Number:
  US09/473,084
• Time in Patent Office: 1,050 Days
• Field of Search: 343/700.MS, 343/702, 455/90, 455/833, 455/834
• US Class Current: 343/700.0MS
• CPC Class Codes: H01Q 1/243 with built-in antennas
• CPC Class Codes: H01Q 19/005 Patch antenna using one or more coplanar parasitic elements
• 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 9/0421 with a shorting wall or a shorting pin at one end of the element H01Q9/0414 takes precedence

Abstract

An antenna assembly, and an associated method, for a radio device, such as a mobile terminal operable in a cellular communication system. The antenna assembly includes an active antenna element and at least a parasitic element. The active antenna element is of a selected lengthwise dimension and is resonant, in isolation, at a first resonant frequency. The parasitic antenna element is positioned proximate to the active antenna element and separated therefrom by a selected separation distance. The selected separation distance is determinative of a reduction in frequency at which the active antenna element is resonant. Thereby, for a given length, the resonant frequency of the active antenna element is reduced, permitting the lengthwise dimensional requirements of the antenna transducer of which the active antenna element is formed to be reduced relative to conventional antenna transducers.

Claims

1. An antenna assembly for radio circuitry operable to communicate radio signals at least within a selected frequency range and having a ground part and a rf (radio frequency) part, said antenna assembly comprising:

a first antenna element of a first lengthwise dimension, L-x, and having a dorsal side portion and a distal side portion, said first antenna element connected at a ground-part-connection location of the dorsal side portion thereof to the ground part of the radio circuitry and connected to the rf part of the radio circuitry at a rf-part-connection location, the rf-part-connection location spaced apart from the ground-part-connection location, said first antenna element, in isolation, resonant about a first resonant frequency, the first resonant frequency about which, in isolation, said first antenna element is resonant being related to an antenna transducer of length L-x; and

a second antenna element also having a dorsal side portion and a distal side portion, said second antenna element spaced apart from said first antenna element by a first selected distance, l, and connected at a ground-part-connection location of the distal side portion thereof to the ground part of the radio circuitry, positioning of said second antenna element at the selected distance from said first antenna element offsetting the first resonant frequency at which said first antenna element is, in isolation, resonant, thereby to be resonant at a first offset frequency, the first offset frequency about which said first antenna element is resonant being related to an antenna transducer, in isolation, of length L, the first offset frequency within the selected frequency range.

2. The antenna assembly of claim 1 wherein the radio circuitry is disposed at a substrate and wherein said first antenna element and said second antenna element are attached to the substrate.

3. The antenna assembly of claim 2 wherein said first antenna element and said second antenna element are translatably attached to the substrate, together translatable between a first translation position and a second translation position.

4. The antenna assembly of claim 1 wherein said first antenna element comprises a body portion extending in a first longitudinal direction and wherein said second antenna element also comprises a body portion, the body portion of said second antenna element extending substantially in the first longitudinal direction.

5. The antenna assembly of claim 1 wherein the dorsal side portion of said first antenna element comprises a back-angled end portion, the ground-part-connection location of said first antenna element positioned at the back-angled end portion thereof.

6. The antenna assembly of claim 5 wherein the distal side portion of said second antenna element comprises a back-angled end portion, the ground-part-connection location of said second antenna element positioned at the back-angled end portion thereof.

7. The antenna assembly of claim 6 wherein portions of said first antenna element extending beyond the bank-angled end portions of the dorsal side portions thereof extends in a first longitudinal direction.

8. The antenna assembly of claim 7 wherein portions of said second antenna element extending beyond the back-angled end portion of the distal side portion thereof extend in a second longitudinal direction, the second longitudinal direction substantially corresponding to the first longitudinal direction.

9. The antenna assembly of claim 8 wherein portions of said first antenna element extending beyond the back-angled end portion of the dorsal side portion thereof are of a first lengthwise dimension and wherein portions of said second antenna element extending beyond the back-angled end portion of the distal side portion thereof are of a second lengthwise dimension, the first and second lengthwise dimensions, respectively, of substantially similar lengths.

10. The antenna assembly of claim 1 further comprising a third antenna element also having a dorsal side portion and a distal side portion, said third antenna element connected at a ground-part-connection location of the dorsal side portion thereof to the ground part of the radio circuitry, said third antenna element forming a parasitic element spaced apart from said first antenna element by a second selected distance, the second selected distance at which said third antenna element is spaced from said first antenna element in part determinative of an antenna-assembly frequency response.

11. The antenna assembly of claim 10 wherein the second selected distance is greater than a sum of a widthwise dimension of said second antenna element and the first selected distance and wherein said second antenna element is positioned between said first antenna element and said third antenna element, respectively.

12. The antenna assembly of claim 10 wherein said first antenna element comprises a body portion extending in a first longitudinal direction and wherein said third antenna element also comprises a body portion, the body portion of said third antenna element extending substantially in the first longitudinal direction.

13. The antenna assembly of claim 1 wherein the dorsal side portion of said first antenna element comprises a back-angled end portion, the ground-part-connection location of said first antenna element positioned at the back-angled end portion thereof.

14. The antenna assembly of claim 13 wherein said third antenna element comprises a Planar Inverted F Antenna.

15. The antenna assembly of claim 1 wherein said first antenna element comprises a Planar Inverted F Antenna.

16. In a method for communicating with a radio device having radio circuitry operable to communicate radio signals at least within a selected frequency range, the radio circuitry mounted at a substrate and having a ground part and a rf part, an improvement of a method for transducing the radio signals, said method comprising:

positioning a first antenna element in a forward-extending direction, the first antenna element of a first lengthwise dimension L-x;

connecting the first antenna element to the ground part and to the rf part of the radio circuitry, thereby to cause the first antenna element, in isolation, to be resonant about a first resonant frequency, the first resonant frequency about which, in isolation, the first antenna element is resonant being related to an antenna transducer of length L-x;

positioning a second antenna element in a reverse-extending direction, spaced apart from the first antenna element by a first selected distance, l;

connecting the second antenna element to the ground part of the radio circuitry, thereby offsetting the first resonant frequency at which the first antenna element, in isolation, is resonant, thereafter to be resonant at a first offset frequency, the first offset frequency about which the first antenna element is resonant being related to an antenna transducer, in isolation, of length L, the first offset frequency within the selected frequency range.

17. The method of claim 16 comprising the additional operations of:

positioning a third antenna element in a forward-extending direction, spaced apart from the second antenna element by a second selected distance; and

connecting the third antenna element to the ground part of the radio circuitry.

18. The method of claim 16 wherein the first antenna element connected during said operation of connecting the first antenna element is translatably connected to the ground part and the rf part of the radio circuitry and wherein the second antenna element connected during said operation of connecting the second antenna element is translatably connected to the ground part of the radio circuitry, the first antenna element and the second antenna element translatable together in unison.

19. The antenna assembly of claim 18 comprising the additional operations of:

determining, for a lengthwise dimension of the first antenna element, a desired offset by which to offset the first resonant frequency; and

selecting the first spaced apart distance at which to position the second antenna element to cause the first resonant frequency to be offset by the desired offset.

20. In a radio device having radio circuitry operable to communicate radio signals, the radio circuitry mounted at a substrate and having a ground part and a rf (radio frequency) part, an improvement of an antenna assembly for transducing the radio signals within a selected frequency range, said antenna assembly comprising:

a first antenna element of a first lengthwise dimension, L-x, said first antenna element extending in a first lengthwise direction and having a dorsal side portion and a distal side portion, said first antenna element connected at the dorsal side portion thereof to the ground part of the radio circuitry, and said first antenna element connected to the rf part of the radio circuitry at a selected distance from the dorsal side portion at which said first antenna element is connected to the ground part, said first antenna element, in isolation, resonant about a first resonant frequency, the first resonant frequency about which, in isolation, said first antenna element is resonant being related to an antenna transducer of length L-x;

a second antenna element of a second selected lengthwise dimension, positioned to have a portion thereof extend in a direction substantially corresponding to the first lengthwise direction in which said first antenna element extends and having a dorsal side portion and a distal side portion, said second antenna element connected at the distal side portion thereof to the ground part of the radio circuitry, said second antenna element spaced apart from said first antenna element by a selected distance, l, thereby to reduce the first resonant frequency at which said first antenna element is resonant, said first antenna element thereby resonant at a reduced, resultant frequency, the reduced, resultant frequency about which said first antenna element is resonant being related to an antenna transducer, in isolation, of length L, the reduced, resultant frequency range.