Compact, low profile, single feed, multi-band, printed antenna

• US 20040056804A1
• Filed: 12/09/2002
• Published: 03/25/2004
• Est. Priority Date: 09/20/2002
• Status: Active Grant

• Current Assignee: Centurion Wireless Technologies Inc (Laird Limited)
• Original Assignee: Centurion Wireless Technologies Inc (Laird Limited)
• Inventors: Kadambi, Govind Rangaswamy, Yarasi, Sripathi, Hebron, Theodore Samuel
• Granted Patent: US 6,956,530 B2
• Time in Patent Office: Days
• US Class Current: 343/700MS
• 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 5/357 using a single feed point
• CPC Class Codes: H01Q 5/371 Branching current paths
• 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

Printed circuit techniques and two-shot molding techniques are used to form a metal radiating element, a metal ground plane element, a metal antenna feed, a metal short-circuiting strip and metal capacitive loading plates within small antennas that are buried within transmit/receive radio-devices such a mobile cellular telephones. Balanced and unbalanced, single-feed, two and three band antennas are provided wherein the radiating element is laterally spaced from the ground plane element, to thereby provide an antenna having a very low profile or height, including antennas wherein the ground plane element and the radiating element are placed coplanar on the same surface of a PCB. A thin dielectric carriage on a PCB allows for the metal capacitive loading plates to be placed on the sidewalls of the dielectric carriage, to thereby provide reactive loading of a radiating element that is on the top surface of the dielectric carriage.

Claims

1. A low profile antenna, comprising:

a printed circuit board having a metal ground plane element on a first portion of one surface of said printed circuit board;

a metal radiating element on a second portion of said one surface of said printed circuit board, said metal radiating element being coplanar with, and laterally spaced from, said ground plane element; and

a metal antenna feed strip extending from said radiating element.

2. The low profile antenna of claim 1 wherein said radiating element is formed in a geometric configuration so as to provide multi-band response for said antenna.

3. The low profile antenna of claim 2 wherein said printed circuit board is contained within a hand-held, transmit/receive, radio communication device, including:

electrical transmit/receive components for said radio communication device on said first portion of said one surface of said printed circuit board;

said electrical components having an output/input terminal;

said metal ground plane element providing a common source of potential such as a ground potential for said electrical components; and

means connecting said antenna feed strip to said output/input terminal.

4. The low profile antenna of claim 1 including:

a short-circuiting metal strip on said one surface of said printed circuit board, said short-circuiting metal strip extending from said second portion of said printed circuit board to said first portion of said printed circuit board, and directly connecting a portion of said radiating element to said ground plane element.

5. The low profile antenna of claim 4 wherein said radiating element is formed in a rectangular-spiral geometric configuration, so as to provide multi-band response for said antenna.

6. The low profile antenna of claim 5 wherein said printed circuit board is contained within a hand-held, transmit/receive, radio communication device, including:

electrical transmit-receive components for said radio communication device on said first portion of said one surface of said printed circuit board;

said electrical components having an output/input terminal;

said metal ground plane element providing a common source of ground potential for said electrical components; and

means connecting said antenna feed strip to said output/input terminal.

7. The low profile antenna of claim 1 wherein said metal radiating element is in the form spiral metal pattern.

8. The low profile antenna of claim 7 wherein said spiral metal pattern comprises a generally rectangular spiral having a plurality of generally straight metal segments.

9. The low profile antenna of claim 8 including a generally L-shaped metal segment extending from one of said plurality of metal segments.

10. A mobile radio-device, comprising:

a printed circuit board having a metal ground plane element on a first portion of said printed circuit board;

electrical circuitry for said mobile radio-device physically associated with said ground plane element, said ground plane element providing a common-electrical-potential connection, such as a ground connection, for said electrical circuitry;

a metal antenna radiating element on a second portion of said printed circuit board, said antenna radiating element being coplanar with, and laterally spaced from, said ground plane element; and

a metal antenna feed strip extending from a first portion of said antenna radiating element to said electrical circuitry.

11. The mobile radio-device of claim 10 wherein said antenna radiating element is formed in a geometric configuration that provides multi-band response for said mobile radio-device.

12. The mobile radio-device of claim 10 including:

a short-circuiting metal strip on said printed circuit board, said short-circuiting metal strip extending from said second portion of said printed circuit board to said first portion of said printed circuit board, and directly connecting a second portion of said antenna radiating element to said ground plane element, said second portion of said antenna radiating element being physically spaced from said first portion of said antenna radiating element.

13. The mobile radio-device of claim 12 wherein said antenna radiating element is formed in a geometric configuration that provides multi-band response for said mobile radio-device.

14. A physically compact radio-device, comprising:

a printed circuit board having a metal ground plane located on a relatively large-area portion of a surface of said printed circuit board;

circuitry for said radio-device physically associated with said ground plane, said ground plane providing a common-electrical-ground connection for said circuitry;

a thin dielectric carriage located on a relatively small-area portion of said surface of said printed circuit board, wherein said small-area portion of said printed circuit board abuts said relatively large-area portion of said printed circuit board;

said dielectric carriage having a plurality of sidewalls whose top surfaces define a top surface of said dielectric carriage and whose bottom surfaces define a bottom surface of said dielectric carriage;

said top surface of said dielectric carriage being generally parallel to said bottom surface of said dielectric carriage;

said bottom surface of said dielectric carriage being located on said second relatively small-area portion of said surface of said printed circuit board;

a metal antenna element on said dielectric carriage, said antenna element being located above and being laterally spaced from, said ground plane;

at least one metal loading strip connected to at least one portion of said antenna element and extending along at least one sidewall of said dielectric carriage; and

a metal antenna feed strip extending from a first portion of said antenna element to said circuitry.

15. The physically compact radio-device of claim 14 wherein said antenna element is (1) located on said top surface of said dielectric carriage so as to be generally parallel to, but not coplanar with, said ground plane, or (2) located on said sidewalls of said dielectric carriage so as to be located above and generally perpendicular to the plane of said ground plane.

16. The physically compact radio-device of claim 15 wherein said antenna element is formed in a geometric configuration that provides multi-band response for said physically compact radio-device.

17. The physically compact radio-device of claim 16 wherein said antenna element is in the form spiral metal pattern.

18. The physically compact radio-device of claim 17 wherein said spiral metal pattern comprises a generally rectangular spiral having a plurality of generally straight metal segments.

19. The physically compact radio-device of claim 18 including a generally L-shaped metal segment extending from one of said plurality of metal segments.

20. The physically compact radio-device of claim 16 wherein said dielectric carriage has a height of about 3 mm as measured between said top surface and said bottom surface of said dielectric carriage.

21. The physically compact radio-device of claim 14 including:

a short-circuiting metal strip directly connecting a second portion of said antenna element to said ground plane, said second portion of said antenna element being physically spaced from said first portion of said antenna element.

22. The physically compact radio-device of claim 21 wherein said antenna element is formed in a geometric configuration that provides multi-band response for said physically compact mobile radio-device.

23. The physically compact radio-device of claim 19 wherein said antenna element is located on said top surface of said dielectric carriage so as to be generally parallel to said ground plane, or wherein said antenna element is located on said sidewalls of said dielectric carriage so as to be generally perpendicular to said ground plane.

24. The physically compact radio-device of claim 20 wherein said dielectric carriage has a height of about 3 mm as measured between said top surface and said bottom surface of said dielectric carriage.

25. The physically compact radio-device of claim 14 wherein said dielectric carriage is constructed of a generally rigid dielectric material having a dielectric constant in the range of from about 2.5 to about 3.0.

26. The physically compact radio-device of claim 22 wherein said dielectric carriage has a height of about 3 mm as measured between said top surface and said bottom surface of said dielectric carriage.

27. The physically compact radio-device of claim 24 wherein said generally rigid dielectric material is selected from a group consisting of polycarbonate, ABS and HDPE.

28. The physically compact radio-device of claim 24 wherein said antenna element is located on said top surface of said dielectric carriage so as to be generally parallel to said ground plane, or wherein said antenna element is located on said sidewalls of said dielectric carriage so as to be generally perpendicular to said ground plane.

29. A physically compact antenna, comprising:

a printed circuit board having a metal ground plane located on a relatively large-area portion of a surface of said printed circuit board;

a thin dielectric carriage located on a relatively small-area portion of said surface of said printed circuit board, wherein said small-area portion of said printed circuit board abuts said relatively large-area portion of said printed circuit board;

said dielectric carriage having a plurality of sidewalls whose top surfaces define a top surface of said dielectric carriage and whose bottom surfaces define a bottom surface of said dielectric carriage;

said top surface of said dielectric carriage being generally parallel to said bottom surface of said dielectric carriage;

said bottom surface of said dielectric carriage being located on said second relatively small-area portion of said surface of said printed circuit board;

a gap formed in one of said sidewalls of said dielectric carriage;

a metal antenna element formed on said sidewalls of said dielectric carriage so as to extend through said gap and so as to be located on both an inner surface and an outer surface of said sidewalls;

said antenna element being located above, being laterally spaced from, and extending generally perpendicular to said ground plane; and

a metal antenna feed strip extending from said antenna element.

30. A physically compact antenna, comprising:

a printed circuit board having a metal ground plane located on a relatively large-area portion of a surface of said printed circuit board;

a thin dielectric carriage located on a relatively small-area portion of said surface of said printed circuit board, wherein said small-area portion of said printed circuit board abuts said relatively large-area portion of said printed circuit board;

said dielectric carriage having a plurality of sidewalls whose top surfaces define a top surface of said dielectric carriage and whose bottom surfaces define a bottom surface of said dielectric carriage;

said top surface of said dielectric carriage being generally parallel to said bottom surface of said dielectric carriage;

said bottom surface of said dielectric carriage being located on said second relatively small-area portion of said surface of said printed circuit board;

a first metal radiating element on said top surface of said dielectric carriage, said first radiating element being located above, being laterally spaced from, and extending generally parallel to said ground plane; and

a second metal radiating element formed on said sidewalls of said dielectric carriage, said second radiating element being located above, being laterally spaced from, and extending generally perpendicular to said ground plane.

31. A physically compact planar monopole antenna, comprising:

a printed circuit board having a metal ground plane located on a relatively large-area portion of a surface of said printed circuit board;

a thin dielectric carriage located on a relatively small-area portion of said surface of said printed circuit board;

said small-area portion of said printed circuit board abutting said relatively large-area portion of said printed circuit board;

said dielectric carriage having a plurality of sidewalls whose top surfaces define a top surface of said dielectric carriage and whose bottom surfaces define a bottom surface of said dielectric carriage;

said top surface of said dielectric carriage being generally parallel to said bottom surface of said dielectric carriage;

said bottom surface of said dielectric carriage being located on said second relatively small-area portion of said surface of said printed circuit board;

a generally flat metal antenna element on said top surface of said dielectric carriage;

said antenna element having a generally U-shaped slot formed therein;

said generally U-shaped slot having an open slot end that is located on one edge of said antenna element;

at least one metal loading plate closely abutting at least one of said sidewalls and extending from said antenna element in a direction toward said surface of said printed circuit board; and

a metal antenna feed strip extending from said one edge of said antenna element.

32. The antenna of claim 31 including:

electrical transmit/receive components on said relatively large-area portion of said printed circuit board; and

means electrically connecting said antenna feed strip to an input/output of said transmit/receive components.

33. The antenna of claim 31 wherein said generally U-shaped slot includes three generally linear slot segments that are connected to form a continuous slot having a closed slot end and having said open slot end.

34. The antenna of claim 31 wherein the antenna is a balanced antenna by virtue of said antenna element being electrically isolated from said ground plane.

35. The antenna of claim 34 including:

electrical transmit/receive components on said relatively large-area portion of said printed circuit board; and

means electrically connecting said antenna feed strip to an input/output of said transmit/receive components.

36. The antenna of claim 31 wherein said antenna is an un-balanced antenna by virtue of short-circuiting metal stub that extends from said edge of said antenna element to electrically connect said antenna element to said ground plane.

37. The antenna of claim 36 wherein said short-circuiting stub is laterally spaced from said antenna feed.

38. The antenna of claim 37 including:

electrical transmit/receive components on said relatively large-area portion of said printed circuit board; and

means electrically connecting said antenna feed strip to an input/output of said transmit/receive components.