Multi-band monopole antennas for mobile communications devices

• US 8,456,365 B2
• Filed: 08/13/2008
• Issued: 06/04/2013
• Est. Priority Date: 12/22/2002
• Status: Active Grant

• Current Assignee: Fractus SA
• Original Assignee: Fractus SA
• Inventors: Pros, Jaume Anguera, Baliarda, Carles Puente
• Primary Examiner(s): Nguyen, Hoang V
• Application Number:
  US12/228,487
• Publication Number:
  US 20090033561A1
• Time in Patent Office: 1,756 Days
• Field of Search: 343/700.MS, 343/702, 343/895, 343/833, 343/834
• US Class Current: 343/700.MS
• 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 21/30 Combinations of separate antenna units operating in different wavebands and connected to a common feeder system
• CPC Class Codes: H01Q 5/307 Individual or coupled radiating elements, each element being fed in an unspecified way
• CPC Class Codes: H01Q 5/371 Branching current paths
• CPC Class Codes: H01Q 9/30 with feed to end of elongated active element, e.g. unipole H01Q9/44 takes precedence
• CPC Class Codes: H01Q 9/40 Element having extended radiating surface
• CPC Class Codes: H01Q 9/42 with folded element, the folded parts being spaced apart a small fraction of the operating wavelength

Abstract

Antennas for use in mobile communication devices are disclosed. The antennas disclosed can include a substrate with a base, a top, a front side and a back side; a first conductor can be located on the first side of the antenna substrate; and a second conductor can be located on the second side of the antenna substrate. The conductors can have single or multiple branches. If a conductor is a single branch it can, for example, be a spiral conductor or a conducting plate. If a conductor has multiple branches, each branch can be set up to receive a different frequency band. A conductor with multiple branches can have a linear branch and a space-filling or grid dimension branch. A conducting plate can act as a parasitic reflector plane to tune or partially tune the resonant frequency of another conductor. The first and second conductors can be electrically connected.

Claims

1. A mobile communication device, comprising:

a device housing;

a printed circuit board, the printed circuit board comprising;

a ground plane layer;

a feeding point;

a communication circuitry, the communication circuitry being mounted on the printed circuit board;

wherein the communication circuitry is coupled to the feeding point and to the ground plane layer;

a multi-band antenna capable of operating at multiple frequency bands, the multi-band antenna including an antenna element;

wherein the antenna element operates in cooperation with the ground plane layer;

the antenna element comprising;

a common conductor;

a first radiating arm connected to the common conductor;

a second radiating arm connected to the common conductor;

wherein the common conductor includes a feeding port, the feeding port being coupled to the feeding point;

wherein at least a portion of the first radiating arm and at least a portion of the second radiating arm are arranged on different planes;

wherein the first radiating arm is at least partially shaped according to a grid-dimension curve; and

wherein the printed circuit board, the communication circuitry, and the multi-band antenna are arranged inside the device housing.

2. The mobile communication device according to claim 1, wherein the first radiating arm comprises a first plurality of segments;

wherein each segment of the first plurality of segments is smaller than 1/10 of a lowest operating free-space wavelength of the multi-band antenna;

wherein the segments are spatially arranged such that each pair of adjacent segments forms a corner; and

wherein no two adjacent and connected segments form another longer straight segment;

and wherein none of said segments intersect with another segment other than to form a closed loop.

3. The mobile communication device according to claim 2, wherein the first plurality of segments comprises at least one curved segment.

4. The mobile communication device according to claim 2, wherein the first plurality of segments comprises at least ten segments.

5. The mobile communication device according to claim 2, wherein the second radiating arm comprises a second plurality of segments;

wherein each segment of the second plurality of segments is smaller than 1/10 of a lowest operating free-space wavelength of the multi-band antenna;

wherein the segments are spatially arranged such that each pair of adjacent segments forms a corner; and

wherein no two adjacent and connected segments form another longer straight segment;

and wherein none of said segments intersect with another segment other than to form a closed loop.

6. The mobile communication device according to claim 5, wherein the first plurality of segments comprises more segments than the second plurality of segments.

7. The mobile communication device according to claim 1, wherein the grid-dimension curve has a grid dimension larger than 1.3.

8. The mobile communication device according to claim 1, wherein the grid-dimension curve has a grid dimension larger than 1.5.

9. The mobile communication device according to claim 1, wherein the second radiating arm is at least partially shaped according to a second grid-dimension curve.

10. The mobile communication device according to claim 9, wherein the grid-dimension curve and the second grid-dimension curve have different lengths.

11. The mobile communication device according to claim 9, wherein the grid-dimension curve and the second grid-dimension curve have different grid dimensions.

12. The mobile communication device according to claim 1, wherein an orthogonal projection of a footprint of the antenna element on a plane of the printed circuit board overlaps the ground plane layer in less than 50% of an area of said footprint.

13. The mobile communication device according to claim 1, comprising:

a dielectric mounting structure having a plurality of surfaces;

wherein at least a portion of the first radiating arm is arranged on a first surface of said plurality of surfaces; and

wherein at least a portion of the second radiating arm is arranged on a second surface of said plurality of surfaces, the second surface being different from the first surface.

14. The mobile communication device according to claim 13, wherein the first surface and the second surface are opposite surfaces of the dielectric mounting structure.

15. A mobile communication device, comprising:

a device housing;

a printed circuit board, the printed circuit board comprising;

a ground plane layer;

a feeding point;

a communication circuitry, the communication circuitry being mounted on the printed circuit board;

wherein the communication circuitry is coupled to the feeding point and to the ground plane layer;

a multi-band antenna capable of operating at multiple frequency bands, the multi-band antenna including an antenna element;

wherein the antenna element is coupled to the feeding point and operates in cooperation with the ground plane layer;

the antenna element comprising;

a first conductor, the first conductor comprising a first radiating arm having a grid-dimension section shaped according to a grid-dimension curve;

a second conductor arranged at a predetermined distance from the first conductor and electromagnetically coupled to the first conductor, the second conductor comprising a planar section; and

wherein the printed circuit board, the communication circuitry, and the multi-band antenna are arranged inside the device housing.

16. The mobile communication device according to claim 15, wherein the first conductor and the second conductor are electrically connected.

17. The mobile communication device according to claim 16, wherein the antenna element comprises a connecting portion that connects the first radiating arm and the planar section.

18. The mobile communication device according to claim 17, wherein a width of the grid-dimension section is smaller than a width of the planar section.

19. The mobile communication device according to claim 15, wherein the grid-dimension curve features a grid dimension larger than 1.3.

20. The mobile communication device according to claim 15, wherein the grid-dimension curve comprises at least ten connected segments;

wherein said segments are each smaller than 1/10 of a lowest operating free-space wavelength of the multi-band antenna;

wherein the segments are spatially arranged such that no two adjacent and connected segments form another longer straight segment;

wherein none of said segments intersect with another segment other than to form a closed loop;

wherein each pair of adjacent segments forms a corner; and

wherein any portion of the grid-dimension curve that is periodic along a fixed straight direction of space is defined by a non-periodic curve that includes at least ten connected segments in which no two adjacent and connected segments define a straight longer segment.

21. The mobile communication device according to claim 15, wherein the multi-band antenna comprises:

a dielectric mounting structure having a plurality of surfaces;

wherein at least a portion of the first radiating arm is arranged on a first surface of said plurality of surfaces; and

wherein at least a portion of the second conductor is arranged on a second surface of said plurality of surfaces, the second surface being different from the first surface.

22. The mobile communication device according to claim 21, wherein the grid-dimension section is arranged on the first surface;

and

wherein the planar section is arranged on the second surface.

23. The mobile communication device according to claim 21, wherein the first surface and the second surface are two opposite surfaces of the dielectric mounting structure.

24. The mobile communication device according to claim 21, wherein the first surface and the second surface are substantially parallel.

25. The mobile communication device according to claim 15, wherein the antenna element further comprises:

a common conductor;

a second radiating arm connected to the common conductor; and

wherein the first radiating arm is connected to the common conductor.

26. The mobile communication device according to claim 25, wherein the second radiating arm comprises a substantially straight section.

27. The mobile communication device according to claim 25, wherein the second radiating arm comprises a second grid-dimension section, the second grid-dimension section being shaped according to a second grid-dimension curve.

28. The mobile communication device according to claim 25, wherein the second radiating arm and the grid-dimension section of the first radiating arm lie on a common surface.

29. The mobile communication device according to claim 25, wherein the grid-dimension section of the first radiating arm extends away from the common conductor along a first direction;

and

wherein the second radiating arm extends away from the common conductor along a second direction, the second direction being substantially parallel to the first direction.

30. The mobile communication device according to claim 29, wherein the antenna element comprises a connecting portion that connects the grid-dimension section and the planar section;

and

wherein the planar section extends away from the connection portion along a direction substantially opposite to the first direction.

31. A mobile communication device, comprising:

a device housing;

a printed circuit board, the printed circuit board comprising;

a ground plane layer;

a feeding point;

a communication circuitry, the communication circuitry being mounted on the printed circuit board;

wherein the communication circuitry is coupled to the feeding point and to the ground plane layer;

a multi-band antenna capable of operating at multiple frequency bands, the multi-band antenna including;

a dielectric mounting structure having a plurality of surfaces;

an antenna element, the antenna element being coupled to the feeding point and operating in cooperation with the ground plane layer;

wherein the antenna element comprises a first radiating arm arranged on two or more surfaces of the plurality of surfaces of the dielectric mounting structure;

the first radiating arm comprising;

a first section shaped according to a grid-dimension curve;

a second section connected to the grid-dimension section, the second section having a width different from a width of the first section; and

wherein the printed circuit board, the communication circuitry, and the multi-band antenna are arranged inside the device housing.

32. The mobile communication device according to claim 31, wherein the first section is arranged on a first surface of said plurality of surfaces;

and

wherein the second section is arranged on a second surface of said plurality of surfaces, the second surface being different from the first surface.

33. The mobile communication device according to claim 32, wherein the first surface and the second surface are opposite surfaces of the dielectric mounting structure.

34. The mobile communication device according to claim 33, wherein the first surface and the second surface are substantially parallel surfaces spaced by a predetermined distance.

35. The mobile communication device according to claim 31, wherein the first section extends along a first direction and the second section extends along a second direction, the second direction being different from the first direction.

36. The mobile communication device according to claim 35, wherein the second direction is substantially opposite to the first direction.

37. The mobile communication device according to claim 31, wherein the antenna element further comprises:

a common conductor;

a second radiating arm;

wherein each of the first radiating arm and the second radiating arm is connected to the common conductor; and

wherein the second radiating arm is arranged on at least one surface of the plurality of surfaces of the dielectric mounting structure.

38. The mobile communication device according to claim 37, wherein said at least one surface is one of the two or more surfaces on which the first radiating arm is arranged.

39. The mobile communication device according to claim 38, wherein the first section of the first radiating arm is arranged on said at least one surface, so that said first section and the second radiating arm are on a common surface of the plurality of surfaces of the dielectric mounting structure.

40. The mobile communication device according to claim 37, wherein the second radiating arm has a uniform width.

41. The mobile communication device according to claim 31, wherein an orthogonal projection of a footprint of the antenna element on a plane of the printed circuit board overlaps the ground plane layer in less than 50% of an area of said footprint.

42. The mobile communication device according to claim 37, wherein the second radiating arm comprises a plurality of segments.

43. The mobile communication device according to claim 37, wherein the second radiating arm is shaped according to a second grid-dimension curve.

44. The mobile communication device according to claim 37, wherein the first section of the first radiating arm is connected to the common conductor and extends away from the common conductor along a first direction;

wherein the second section of the first radiating arm is connected to the first section and extends along a second direction; and

wherein the second radiating arm extends away from the common conductor along a direction substantially opposite to the second direction.

45. The mobile communication device according to claim 31, wherein the mobile communication device operates as one of a personal digital assistant and a cellular telephone.