Antenna

• US 6,614,400 B2
• Filed: 07/20/2001
• Issued: 09/02/2003
• Est. Priority Date: 08/07/2000
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Egorov, Igor
• Primary Examiner(s): Nguyen, Hoang
• Application Number:
  US09/908,817
• Publication Number:
  US 20020019247A1
• Time in Patent Office: 774 Days
• Field of Search: 343/702, 343/700.MS, 343/895, 343/846
• US Class Current: 343/702
• 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 5/357 using a single feed point
• CPC Class Codes: H01Q 5/371 Branching current paths
• CPC Class Codes: H01Q 5/378 Combination of fed elements with parasitic elements
• CPC Class Codes: H01Q 9/0421 with a shorting wall or a shorting pin at one end of the element H01Q9/0414 takes precedence
• CPC Class Codes: H01Q 9/0442 with particular tuning means

Abstract

The present invention relates to a built-in folded PIFA antenna for a radio communication device (400, 450) and a mobile phone (400) containing the same antenna. The built-in antenna comprises a first part (500) tuned to a first and a second frequency band, and a second part (600) electro-magnetically interacting with the first part (500) and galvanically separated from the first part. While the second part (600) interacts with the first part, the antenna is tuned to a third frequency band. The first part (500) is folded to form a first element (510) and a second element (520), wherein the second element (520) is folded approximately 180 degrees in relation to the longitudinal axis of the first element (520).

Claims

1. A communication device in a radio communication system, the device comprising:

a first interface for receiving information from a user;

a second interface for transmitting information to said user; and

a built-in multiple band antenna comprising a first part and a second part, said first part being tuned to at least a first frequency band and a second frequency band;

wherein said second part is tuned to at least a third frequency band when electro-magnetically interacting with said first part.

2. The communication device according to claim 1, wherein:

said first interface contains one or more of a group consisting of a microphone, a keypad, a touchpad, a radio-port, an IR-port, a computer-port and a Bluetooth-port; and

said second interface contains one or more of a group consisting of a speaker, a display, a radio-port, a computer-port, and a Bluetooth-port.

3. The communication device according to claim 1, wherein said second part is galvanically separated from said first part.

4. The communication device according to claim 1, wherein said first part has a first ground pin connected to a ground plane and to a feeding pin of the device.

5. The communication device according to claim 4, wherein said second part has a second ground pin connected to the ground plane and to a main element with an open end.

6. The communication device according to claim 1, wherein said first part is folded to form a first element and a second element, said first element comprising a first ground pin and a feeding pin, and said second element comprising a second ground pin and an open end.

7. The communication device according to claim 6, wherein the second element is folded at least 90 degrees in relation to a longitudinal axis of the first element.

8. The communication device according to claim 6, wherein the second element is folded approximately 180 degrees in relation to a longitudinal axis of the first element.

9. The communication device according to claim 6, wherein said first element of said first part, said second element of said first part, and said main element of said second part, are spaced apart and electrically separated from said ground plane by one of a group consisting of a dielectric substrate, legs, a plastic substrate and a ceramic substrate.

10. The communication device according to claim 6 wherein said main element of the second part is arranged in close vicinity of, and in parallel with, the first element of the first part.

11. The communication device according to claim 6, wherein said second ground pin of the second part is placed in close vicinity of the feeding pin of the first part.

12. The communication device according to claim 6, wherein said open end of the second element is bent down towards the ground plane to increase an electrical length of the second element without affecting its physical width W.

13. The communication device according to claim 6, wherein said open end of the main element is bent down towards the ground plane to increase an electrical length of the main element without affecting its physical width W.

14. The communication device according to claim 6 wherein a slot between the first and the second elements of the first part has a width of between approximately 1 to 3 mm.

15. The communication device according to claim 6 wherein the first and the second elements of the first part, and the second part have different lengths and widths to achieve an arbitrary tuning to a specific frequency.

16. The communication device according to claim 6 further comprising:

a substrate of a predetermined thickness, onto which said first part and second part are mounted;

wherein said substrate is mounted on a PCB comprising said ground plane.

17. The communication device according to claim 16, wherein said substrate is a ceramic substrate or a plastic substrate.

18. The communication device according to claim 1 wherein said second part is arranged in close vicinity of, and in parallel with, the first part.

19. The communication device according to claim 1, wherein said first frequency band corresponds to GSM, said second frequency band corresponds to DCS and said third frequency band corresponds to PCS.

20. The communication device according to claim 1, wherein the built-in multiple band antenna has a length of approximately 20 mm, a width of approximately 45 mm and a height over ground of approximately 8 mm.

21. The communication device according to claim 1, wherein said built-in multiple band antenna is attached to a back cover of said communication device.

22. A built-in antenna for a radio communication device, comprising:

a first part tuned to at least a first frequency band and a second frequency band; and

a second part disposed to electro-magnetically interact with said first part, said second part being tuned to at least a third frequency band when electromagnetically interacting with said first part.

23. The built-in antenna according to claim 22, wherein said second part is galvanically separated from said first part.

24. The built-in antenna according to claim 22, wherein said first part comprises a first ground pin and a feeding pin, the first ground pin being disposed to connect to a ground plane and the feeding pin being disposed to connect to a transmitter/receiver.

25. The built-in antenna according to claim 24, wherein said second part comprises a second ground pin and a main element, the second ground pin being disposed to connect to the ground plane, and the main element having an open end.

26. The built-in antenna according to claim 22, wherein said first part is folded to form a first element and a second element, said first element comprising a first ground pin and a feeding pin, and said second element comprising a second ground pin and an open end.

27. The built-in antenna according to claim 26, wherein the second element is folded at least 90 degrees in relation to a longitudinal axis of the first element.

28. The built-in antenna according to claim 26, wherein the second element is folded approximately 180 degrees in relation to a longitudinal axis of the first element.

29. The built-in antenna according to claim 26, wherein the first element of said first part, said second element of said first part, and the main element of said second part, are spaced apart and electrically separated from said ground plane by one of a group consisting of a dielectric substrate, legs, a plastic substrate and a ceramic substrate.

30. The built-in antenna according to claim 26, wherein said main element of the second part is arranged in close vicinity of, and in parallel with, the first element of the first part.

31. The built-in antenna according to claim 26, wherein said second ground pin is placed in close vicinity of the feeding pin of the first part.

32. The built-in antenna according to claim 26, wherein said open end of the second element is bent down towards the ground plane to increase an electrical length of the second element without affecting its physical width W.

33. The built-in antenna according to claim 26, wherein said open end of the main element is bent down towards the ground plane to increase an electrical length of the main element without affecting its physical width W.

34. The built-in antenna according to claim 26, wherein a slot between the first and the second element of the first part has a width of approximately 1 to 3 mm.

35. The built-in antenna according to claim 26, wherein the first and the second elements of the first part, and the second part have different lengths and widths to achieve an arbitrary tuning to a specific frequency.

36. The built-in antenna according to claim 26, further comprising:

a substrate with a predetermined thickness, onto which said first part and second part are mounted;

wherein said substrate is mounted on a PCB comprising said ground plane.

37. The built-in antenna according to claim 36 wherein said substrate is a ceramic substrate or a plastic substrate.

38. The built-in antenna according to claim 36, wherein said PCB comprising the substrate is mounted on a chassis inside a radio communication device.

39. The built-in antenna according to claim 22, wherein said second part is arranged in close vicinity of, and in parallel with, the first part.

40. The built-in antenna according to claim 22, wherein said first frequency band corresponds to GSM, said second frequency band corresponds to DCS and said third frequency band corresponds to PCS.

41. The built-in antenna according to claim 22, wherein the built-in multiple band antenna has a length of approximately 20 mm, a width of approximately 45 mm and a height over ground plane of approximately 8 mm.

42. The built-in antenna according to claim 22, wherein said built-in antenna has an arbitrary two or three-dimensional shape.

43. The built-in antenna according to claim 22, wherein the first part has a length corresponding to the first frequency band within which it is made resonant, and to the second frequency band within which it is made resonant, said second frequency band being approximately twice as high as said first frequency band.

44. The built-in antenna according to claim 22, wherein the second part has a length corresponding to approximately ¼

wavelength of the third frequency to which it is made resonant.

45. The built-in antenna according to claim 22, wherein said antenna is attached to a back cover of a mobile communication device.