Multiple antenna diversity for wireless LAN applications

• US 20030146876A1
• Filed: 12/06/2002
• Published: 08/07/2003
• Est. Priority Date: 12/07/2001
• Status: Active Grant

• Current Assignee: SkyCross Co., Ltd.
• Original Assignee: SkyCross, Inc.
• Inventors: Caimi, Frank M., Kralovec, Jay A., Hendler, Jason M., Greer, Kerry L.
• Granted Patent: US 7,253,779 B2
• Time in Patent Office: Days
• US Class Current: 343/702
• CPC Class Codes: H01Q 11/14 with parts bent, folded, shaped or screened or with phasing impedances, to obtain desired phase relation of radiation from selected sections of the antenna or to obtain desired polarisation effect H01Q11/20 takes precedence
• CPC Class Codes: H01Q 13/20 Non-resonant leaky-waveguide or transmission-line antennas; Equivalent structures causing radiation along the transmission path of a guided wave
• CPC Class Codes: H01Q 21/24 Combinations of antenna units polarised in different directions for transmitting or receiving circularly and elliptically polarised waves or waves linearly polarised in any direction circularly polarised patch antennas H01Q9/0428; circularly polarised horns H01Q13/0241; cross-polarised horns H01Q13/0258; polarisation converters H01Q15/242; cross-polarised rear feeds H01Q19/136; crossed polarisation dual antenna H01Q25/001
• CPC Class Codes: H01Q 21/28 Combinations of substantially independent non-interacting antenna units or systems multiple beam H01Q25/00
• CPC Class Codes: H01Q 7/00 Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
• CPC Class Codes: H01Q 9/36 with top loading

Abstract

An antenna system comprising a plurality of antennas designed and oriented to provide one or more of radiation pattern, signal polarization and spatial diversity. The various diversity operational characteristics are achieved by using similar antennas physically oriented to provide the diversity attributes or by using dissimilar antennas, that is, antennas having different radiation pattern and/or signal polarization characteristics.

Claims

1. An antenna system comprising at least two antennas for providing diversity operation, the antenna system comprising:

a first antenna having first signal polarization and first radiation pattern characteristics; and

a second antenna having second signal polarization and second radiation pattern characteristics different from the first signal polarization and the first radiation pattern characteristics.

2. The antenna system of claim 1 wherein the first signal polarization characteristic is selected from among vertical signal polarization, horizontal signal polarization and circular signal polarization.

3. The antenna system of claim 1 wherein the first radiation pattern characteristic is selected from among an omnidirectional pattern, an elevation pattern and an isotropic pattern.

4. The antenna system of claim 1 wherein the first and the second antennas are mounted on a planar structure, and wherein the first and the second antennas are connected to a common ground plane disposed on the planar structure.

5. The antenna system of claim 4 wherein the planar structure comprises a printed circuit board.

6. The antenna system of claim 1 wherein the first and the second antennas are spaced apart to provide spatial diversity.

7. The antenna system of claim 1 further comprising a controller wherein the controller determines whether the first antenna or the second antenna is operative in response to a measured signal quality metric.

8. The antenna system of claim 7 wherein both the first antenna and the second antenna are operative in response to the measured signal quality metric.

9. The antenna system of claim 1 wherein the first and the second antennas are operative in a wireless local area network.

10. An antenna system comprising at least two antennas for providing diversity operation, the antenna system comprising:

a first antenna having a first signal polarization characteristic;

a second antenna having second signal polarization characteristic different from the first signal polarization characteristic;

a controller for selecting the operative antenna from between the first antenna and the second antenna based on a provided signal quality metric; and

wherein the first and the second antenna are mounted on a planar structure having a ground plane disposed thereon, and wherein the first and the second antennas are connected to the ground plane.

11. The antenna system of claim 10 wherein the first and the second antennas are spaced apart to provide spatial diversity.

12. An antenna system comprising at least two antennas for providing diversity operation, the antenna system comprising:

a first antenna having a first radiation pattern characteristic;

a second antenna having second radiation pattern characteristic different from the first radiation pattern characteristic;

a controller for selecting the operative antenna from between the first antenna and the second antenna based on a provided signal quality metric; and

wherein the first and the second antenna are mounted on a planar structure having a ground plane disposed thereon, and wherein the first and the second antennas are connected to the ground plane.

13. The antenna system of claim 12 wherein the first and the second antennas are spaced apart to provide spatial diversity.

14. An antenna system comprising at least two antennas for providing diversity operation, the antenna system comprising:

a first antenna;

a second antenna oriented with respect to the first antenna to provide one or both of signal polarization diversity and radiation pattern diversity with respect to the first antenna;

a controller for selecting the operative antenna from between the first antenna and the second antenna based on a provided signal quality metric;

wherein the first and the second antennas are mounted on a planar structure, and wherein the first and the second antennas are connected to a common ground plane disposed on the planar structure.

15. The antenna system of claim 14 wherein the first and the second antennas arc spaced apart to provide spatial diversity.

16. The antenna system of claim 15 wherein the first and the second antennas are spaced apart by a fraction of the operational wavelength to provide spatial diversity.

17. A antenna system comprising a plurality of antennas for providing diversity operation, the antenna system comprising:

a first pair of antennas having different signal polarization characteristics;

a second pair of antennas having different radiation pattern characteristics;

a controller responsive to both the first and the second pairs of antennas for determining the operative antenna from the first pair of antennas and for determining the operative antenna from the second pair of antennas in response to a measured signal quality metric.

18. The antenna system of claim 17 further comprising a third pair of antennas in a spaced-apart orientation for providing spatial diversity.

19. The antenna system of claim 17 wherein the antennas of the first pair of antennas and the antennas of the second pair of antennas are spaced apart to provide spatial diversity operation.

20. An antenna system providing selectable antenna performance characteristics, comprising:

a plurality of radiation pattern diverse antennas each having a gain and a radiation pattern characteristic; and

a controller for selecting, in response to a signal quality metric, an antenna having the desired gain with the desired antenna pattern from among the plurality of antennas.

21. The antenna system of claim 20 wherein the plurality of antennas are spaced apart to provide spatial diversity.

22. The antenna system of claim 21 wherein the plurality of antennas have different signal polarization characteristics.

23. For operation in a wireless local area network communications system, an antenna system comprising:

a first antenna having first signal polarization characteristics and first radiation pattern characteristics;

a second antenna having second signal polarization characteristics and second radiation pattern characteristics;

wherein the first and the second antennas are mounted on a common substrate;

a determined signal quality metric; and

a controller for selecting the operative antenna from between the first antenna and the second antenna in response to signal quality metric.

24. The antenna system of claim 23 wherein the common substrate comprises a ground plane to which the first and the second antennas are electrically connected.

25. The antenna system of claim 23 wherein the first and the second antennas are spaced apart a distance determined by the operational wavelength.