Multiple-Antenna Systems With Enhanced Isolation and Directivity

• US 20130093641A1
• Filed: 12/03/2012
• Published: 04/18/2013
• Est. Priority Date: 07/19/2010
• Status: Active Grant

• Current Assignee: Laird Technologies Incorporated (DuPont de Nemours, Inc.)
• Original Assignee: Laird Technologies Incorporated (DuPont de Nemours, Inc.)
• Inventors: Ng, Kok Jiunn, Ng, Tze Yuen
• Granted Patent: US 9,153,873 B2
• Time in Patent Office: Days
• US Class Current: 343/841
• CPC Class Codes: H01Q 1/521 reducing the coupling between adjacent antennas
• CPC Class Codes: H01Q 21/205 providing an omnidirectional coverage turnstile aerials H01Q21/26
• 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

Exemplary embodiments are provided of multiple-antenna systems with enhanced and/or good isolation and directivity. In one exemplary embodiment, a system generally includes a ground plane and two or more antenna elements coupled to the ground plane. The system also includes two or more low frequency isolators/reflectors and two or more high frequency isolators/reflectors coupled to the ground plane.

Claims

1. A system comprising:

a ground plane

two or more antenna elements coupled to the ground plane;

two or more low frequency isolators/reflectors coupled to the ground plane; and

two or more high frequency isolators/reflectors coupled to the ground plane.

2. The system of claim 1, wherein each antenna element is configured for multi-band operation such that each antenna element is operable within a first frequency range and a second frequency range.

3. The system of claim 2, wherein:

the first frequency range is from about 2.4 gigahertz to about 2.5 gigahertz, and the second frequency range is from 4.9 gigahertz to 5.875 gigahertz; and

/or

the first frequency range is the 2.45 gigahertz band, and the second frequency range is the 5 gigahertz band.

4. The system of claim 1, wherein:

the low frequency isolators/reflectors have inverted U-shaped configurations; and

/or

the high frequency isolators/reflectors have inverted U-shaped configurations.

5. The system of claim 1, wherein:

each of the low frequency isolators/reflectors includes two vertical sections and a horizontal section that is generally parallel with the ground plane; and

each of the high frequency isolators/reflectors includes two vertical sections and a horizontal section that is generally parallel with the ground plane.

6. The system of claim 1, wherein the low frequency isolators/reflectors and high frequency isolators/reflectors are positioned relative to the antenna elements for increasing isolation between the antenna elements and/or for increasing directivity of each said antenna element in the direction of the sector that said antenna element serves.

7. The system of claim 1, wherein the antenna includes:

three antenna elements, three low frequency isolators/reflectors, and three high frequency isolators/reflectors;

or

six antenna elements, six low frequency isolators/reflectors, and six high frequency isolators/reflectors.

8. The system of claim 1, further comprising two or more coaxial cables coupled to the two or more antenna elements, respectively, for feeding the antenna elements.

9. The system of claim 1, wherein each antenna element comprises first and second radiating arms and a feeding element, the first and second radiating arms and feeding element comprising electrically-conductive traces on the same side of a circuit board.

10. The system of claim 1, wherein the antenna elements comprise one or more of a monopole antenna, an inverted F antenna (IFA), and/or a planar inverted F antenna (PIFA).

11. The system of claim 1, wherein the high and low frequency isolators/reflectors are configured to be operable as both isolators and reflectors.

12. The system of claim 1, wherein the antenna includes the same number of antenna elements, low frequency isolators/reflectors, and high frequency isolators/reflectors.

13. The system of claim 1, wherein:

the ratio of antenna elements to low frequency isolators/reflectors is one-to-one; and

/or

the ratio of antenna elements to high frequency isolators/reflectors is one-to-one; and

/or

the ratio of low frequency isolators/reflectors to high frequency isolators/reflectors is one-to-one.

14. The system of claim 1, wherein the system is a multiple input multiple output (MIMO) antenna system.

15. The system of claim 1, wherein:

the antenna elements are mounted to the ground plane along a circumference of a circular portion of the ground plane such that the antenna elements are equidistant from a center of the circular portion of the ground plane and such that the antenna elements are spaced equally apart from each other and such that a one hundred twenty degree (120°

) arc is defined between the mounting points of two adjacent antenna elements and the center of the circular portion of the ground plane; and

/or

the low frequency isolators/reflectors are in a spoked configuration centered at the center of the circular portion of the ground plane, such that the low frequency isolators/reflectors are positioned about the center of the circular portion of the ground plane and extend outwardly in a direction away from the center of the circular portion of the ground plane; and

/or

each of the high frequency isolators/reflectors is between a corresponding one of the antenna elements and the center of the circular portion of the ground plane.

16. The system of claim 15, wherein the circular portion of the ground plane is an imaginary or reference circle on a surface of the ground plane.

17. A system comprising:

a ground plane including a circular portion having a circumference and a center;

a plurality of antenna elements mounted to the ground plane along the circumference of the circular portion of the ground plane, the antenna elements equidistant from the center of the circular portion of the ground plane, the antenna elements spaced equally apart from each other such that a one hundred twenty degree (120°

) arc is defined between mounting points of two adjacent antenna elements and the center of the circular portion of the ground plane;

a plurality of low frequency isolators/reflectors in a spoked configuration centered at the center of the circular portion of the ground plane, such that the low frequency isolators/reflectors are positioned about the center of the circular portion of the ground plane and extend outwardly in a direction away from the center of the circular portion of the ground plane; and

/or

a plurality of high frequency isolators/reflectors, each placed between a corresponding one of the antenna elements and the center of the circular portion of the ground plane.

18. The system of claim 17, wherein:

each of the low frequency isolators/reflectors include two vertical sections and a horizontal section that is generally parallel with the ground plane, and defining an inverted U-shaped configuration for each of the low frequency isolators/reflectors; and

each of the high frequency isolators/reflectors include two vertical sections and a horizontal section that is generally parallel with the ground plane, and defining an inverted U-shaped configuration for each of the high frequency isolators/reflectors.

19. The system of claim 17, wherein:

the circular portion of the ground plane is an imaginary or reference circle on a surface of the ground plane; and

/or

the antenna includes the same number of antenna elements, low frequency isolators/reflectors, and high frequency isolators/reflectors, such that the ratio of antenna elements to low frequency isolators/reflectors is one-to-one and such that the ratio of antenna elements to high frequency isolators/reflectors is one-to-one.

20. A multiple input multiple output (MIMO) antenna system, the antenna system comprising:

two or more antenna elements; and

two or more isolators/reflectors positioned relative to the antenna elements for increasing isolation between the antenna elements and for increasing directivity of each said antenna element in the direction of the sector that said antenna element serves.