WIDEBAND, HIGH ISOLATION TWO PORT ANTENNA ARRAY FOR MULTIPLE INPUT, MULTIPLE OUTPUT HANDHELD DEVICES

• US 20100238072A1
• Filed: 03/17/2009
• Published: 09/23/2010
• Est. Priority Date: 03/17/2009
• Status: Active Grant

• Current Assignee: Malikie Innovations Limited (Key Patent Innovations Limited)
• Original Assignee: Research In Motion Limited (Blackberry Limited)
• Inventors: Rao, Qinjian, Wang, Dong, Ayatollahi, Mina
• Granted Patent: US 8,085,202 B2
• Time in Patent Office: Days
• 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 1/48 Earthing means; Earth screens; Counterpoises
• CPC Class Codes: H01Q 1/521 reducing the coupling between adjacent antennas
• CPC Class Codes: H01Q 13/106 Microstrip slot antennas patch antenna elements H01Q9/0407
• CPC Class Codes: H01Q 21/28 Combinations of substantially independent non-interacting antenna units or systems multiple beam H01Q25/00
• CPC Class Codes: H01Q 9/42 with folded element, the folded parts being spaced apart a small fraction of the operating wavelength

Abstract

A multiple input-multiple output antenna assembly with high isolation between the antennas is disclosed. The antenna assembly includes a substrate with a ground layer at its surface. Two antennas are disposed opposing each other on the substrate. An isolation element in a form of a patterned slot is interposed between the first and second antennas on the ground plane. A first signal port is provided for applying a first signal to excite the first antenna and a second signal port is provided for applying a second signal to excite the second antenna. The isolation element provides isolation that inhibits electromagnetic propagation between the two antennas.

Claims

1. An antenna assembly for a wireless communication device comprising:

a ground plane;

a first radiating element disposed on the ground plane;

a second radiating element disposed on the ground plane and spaced apart from the first radiating element by at least one-tenth of a wavelength of a resonant frequency of the second radiating element; and

at least one isolating element interposed on the ground plane between the first radiating element and the second radiating element, wherein the at least one isolating element comprises a meandering slot.

2. The antenna assembly as recited in claim 1 wherein the first and the second radiating elements have substantially identical shapes and oppose each other across a width of the ground plane.

3. The antenna assembly as recited in claim 1 wherein at least one of the first and the second radiating elements comprises an inverted F antenna of an electrically conductive material.

4. The antenna assembly of claim 1 wherein the ground plane comprises a substrate and a layer of electrically conductive material disposed on a surface of the substrate.

5. The antenna assembly of claim 4 wherein the first radiating element and the second radiating element each comprise a slot in a form of an elongated opening in the layer of electrically conductive material, each slot extending inward from a opposing edge of the ground plane and longitudinally parallel to a common edge of the ground plane.

6. The antenna assembly of claim 5 wherein the at least one isolating element comprises an slot in the common edge of the ground plane, disposed at equal distances from the first and the second radiating elements.

7. The antenna assembly of claim 4 wherein at least one of the first and second radiating elements comprises an L-shaped slot, extending from an edge of the ground plane.

8. The antenna assembly of claim 4 wherein the at least one isolating element comprises a slot in the layer of electrically conductive material, having a meandered pattern that starts at an edge of the layer of electrically conductive material.

9. The antenna assembly of claim 4 wherein the at least one isolating element comprises a slot through a thickness of the layer of electrically conductive material, wherein the slot includes a first leg that extends orthogonally inward from an edge of the layer of electrically conductive material and has an inner end from which a second leg extends parallel to the edge and toward the first radiating element terminating at a first remote end, a third leg projecting from the remote end and away from the edge until terminating at a second remote end, and a fourth leg extending from the second remote end parallel to the edge and toward the second radiating element.

10. The antenna assembly of claim 4 comprising first and second isolating elements, each comprising an L-shaped slot formed through the layer of electrically conductive material and having a longitudinal first leg extending inward from an edge of the layer of electrically conductive material and a shorter second leg contiguous with and extending perpendicular to the first leg, and the second leg extending towards a respective one of the first and second radiating elements.

11. The antenna assembly of claim 1 wherein the at least one isolating element is disposed at equal distances from the first and the second radiating elements.

12. An antenna assembly for a wireless communication device comprising:

a ground plane formed by a layer of electrically conductive material on a substrate of non-conductive material, wherein the layer of electrically conductive material has a thickness;

a first slot antenna formed by a first radiation slot in the layer of electrically conductive material;

a second slot antenna formed by a second radiation slot in the layer of electrically conductive material and spaced from the first slot antenna by at least one-tenth wavelength of a resonant frequency of the second slot antenna;

a first isolation slot formed in the layer of electrically conductive material and located between the first slot antenna and the second slot antenna, wherein the first isolation slot comprises a slot having a meandered pattern that starts at an edge of the layer of electrically conductive material;

a first signal port coupled to the first slot antenna; and

a second signal port coupled to the second slot antenna, wherein the first radiation slot, the second radiation slot and the first isolation slot all pass through the thickness of the layer of electrically conductive material.

13. The antenna assembly of claim 12 wherein the first radiation slot is linear;

and the second radiation slot is linear and aligned parallel to the first radiation slot.

14. The antenna assembly of claim 12 wherein the first radiation slot and the second radiation slot comprises an L-shape.

15. The antenna assembly of claim 12 wherein the first isolation slot comprises an L-shape.

16. The antenna assembly of claim 12 further comprising a second isolation slot formed through the thickness of the layer of electrically conductive material and located between the first radiation slot antenna and the first isolation slot.