Multi-band antenna

• US 20060017635A1
• Filed: 07/20/2004
• Published: 01/26/2006
• Est. Priority Date: 07/20/2004
• Status: Active Grant

• Current Assignee: Nokia Technologies Oy (Nokia Corporation)
• Original Assignee: Nokia Corporation
• Inventors: Zheng, Ming
• Granted Patent: US 7,307,591 B2
• Time in Patent Office: Days
• US Class Current: 343/748
• CPC Class Codes: H01Q 19/005 Patch antenna using one or more coplanar parasitic elements
• CPC Class Codes: H01Q 5/357 using a single feed point
• CPC Class Codes: H01Q 7/00 Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
• CPC Class Codes: H01Q 9/065 Microstrip dipole antennas patch antenna H01Q9/0407
• 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 comprising a feed point, a ground point and a conductive track that extends from the feed point and returns to the ground point and means for locally increasing the reactance of the antenna track at a first position coincident with a maximum electromagnetic field associated with at least one of the plurality of resonant frequencies.

Claims

1. An antenna having a plurality of resonant frequencies and comprising a feed point, a ground point and a conductive track that extends from the feed point and returns to the ground point and means for locally increasing the reactance of the antenna track at a first position coincident with a maximum electromagnetic field associated with at least one of the plurality of resonant frequencies.

2. An antenna as claimed in claim 1, wherein the means for locally increasing reactance comprises localised reactive loading of the antenna track at the first position.

3. An antenna as claimed in claim 1, wherein the means for locally increasing the reactance comprises localised capacitive loading at the first position, wherein the first position is coincident with a maximum E-field associated with the at least one of the plurality of resonant frequencies.

4. An antenna as claimed in claim 3, wherein the means for locally increasing the reactance comprises localised capacitive loading at a second position, wherein the second position is coincident with a maximum E-field associated with at least one of the plurality of resonant frequencies.

5. An antenna as claimed in claim 3, wherein the means for locally increasing the reactance comprises localised inductive loading at a third position, wherein the third position is coincident with a maximum H-field associated with at least one of the plurality of resonant frequencies.

6. An antenna as claimed in claim 3, wherein the localised capacitive loading comprises a locally increased conductive track area compared to adjacent portions of the conductive track.

7. An antenna as claimed in claim 3, wherein the localised capacitive loading arises from the location of the ground point adjacent but separated from the first point.

8. An antenna as claimed in claim 3, wherein the conductive track has a plurality of bends including at least one bend at the first position.

9. An antenna as claimed in claim 8, wherein the at least one bend is an acute angled bend.

10. An antenna as claimed in claim 3, wherein the first position is a (2*a_d−

1)/4*n_d along the length of the conductive track, where ad is equal to one of 1, . . . , 2n_d and n_d is a natural number.

11. An antenna as claimed in claim 3, wherein the first position is a (2*a_m−

1)/((2n_m+1)*2) along the length of the conductive track, where am is equal to one of 1, . . . , 2n_m+1 and n_m is a whole number.

12. An antenna as claimed in claim 3, wherein the first position is half way along the length of the conductive track.

13. An antenna as claimed in claim 1, wherein the means for locally increasing the reactance comprises localised inductive loading at the first position, wherein the first position is coincident with a maximum H-field associated with at least one of the plurality of resonant frequencies.

14. An antenna as claimed in claim 13, wherein the localised inductive loading comprises a locally decreased conductive track area.

15. An antenna as claimed in claim 13, wherein the first position is a b_d/2n_d along the length of the conductive track where b_d is equal to one of 0, . . . , 2n_d and n_d is a natural number.

16. An antenna as claimed in claim 13, wherein the first position is a b_m/(2n_m+1) along the length of the conductive track where b_m is equal to one of 0, . . . , 2n_m+1 and n_m is a whole number.

18. An antenna as claimed in claim 1 wherein the conductive track lies in a single plane parallel to a ground plane.

19. An antenna as claimed in claim 1 wherein the conductive track lies in a single plane not parallel to a ground plane.

20. An antenna as claimed in claim 1, wherein the conductive track has a plurality of acute bends.

21. An antenna as claimed in claim 1 wherein the conductive track forms two arms that extend from a point of mutual contact in orthogonal directions.

22. An antenna as claimed in claim 1 used as an internal antenna of a cellular radio communications terminal.

31. A transceiver device comprising an antenna as claimed in claim 1.

17. An antenna as claimed in 13, wherein the means for locally increasing the reactance comprises localised inductive loading at a second position, wherein the second position is coincident with a maximum H-field associated with at least one of the plurality of resonant frequencies.

23. An antenna having a plurality of resonant frequencies and comprising a feed point, a ground point and a conductive track that extends from the feed point and returns to the ground point and further comprising means for locally raising the capacitance of the antenna track at a first position coincident with a maximum electric field associated with at least one of the plurality of resonant frequencies.

24. An antenna as claimed in claim 23, wherein the first position is a (2*a_d−

1)/4*n_d along the length of the conductive track where a_d=1, . . . , 2n_d and n_d is a natural number.

25. An antenna as claimed in claim 23, wherein the first position is a (2*a_m−

1)/(2n_m+1) along the length of the conductive track where a_m=1, . . . , 2n_m+1 and n_m is a whole number.

26. An antenna as claimed in claim 23, wherein the first position is half way along the length of the conductive track.

27. An antenna having a plurality of resonant frequencies and comprising a feed point, a ground point and a conductive track that extends from the feed point and returns to the ground point and further comprising means for locally raising the inductances of the antenna track at positions coincident with maximum H fields associated with at least one of the plurality of resonant frequencies.

28. An antenna having a plurality of resonant frequencies and comprising a feed point, a ground point and a conductive track that extends from the feed point and returns to the ground point and further comprising means for locally raising the inductance of the antenna track at positions ⅓

and ⅔

way along the conductive track.

29. An antenna having a plurality of resonant frequencies and comprising a feed point, a ground point and a conductive track that extends from the feed point and returns to the ground point and further comprising means for locally raising the capacitance of the antenna track at a position half way along the conductive track.

30. (canceled)