DUAL ROLE ANTENNA ASSEMBLY

• US 20160204519A1
• Filed: 01/14/2015
• Published: 07/14/2016
• Est. Priority Date: 01/14/2015
• Status: Active Grant

• Current Assignee: SkyWave Mobile Communications Incorporated (ORBCOMM Incorporated)
• Original Assignee: SkyWave Mobile Communications Incorporated (ORBCOMM Incorporated)
• Inventors: Lafleur, Phil, Roscoe, David
• Granted Patent: US 10,615,499 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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 3/24 varying the orientation by switching energy from one active radiating element to another, e.g. for beam switching
• CPC Class Codes: H01Q 5/50 Feeding or matching arrangements for broad-band or multi-band operation
• 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 9/0428 radiating a circular polarised wave
• CPC Class Codes: H01Q 9/0442 with particular tuning means

Abstract

A dual role antenna assembly operable for use with GEO and LEO/MEO satellites has at least two curled inverted-F substantially omnidirectional antennas mounted on a ground plane. The antennas have asymmetrical gain patterns favoring certain sectors and are oriented such that the favored sectors of the different antenna face different directions. A controller selects the antenna for connection to an RF front-end in accordance with predetermined performance criteria.

Claims

1. A dual role antenna assembly operable for use with GEO and LEO/MEO satellites, comprising:

a ground plane;

at least two curled inverted-F substantially omnidirectional antennas mounted on the ground plane, said antennas having asymmetrical gain patterns favoring certain sectors, and said antennas being oriented such that the favored sectors of the different antenna face different directions, and

an RF beam selection switch for selectively connecting said antenna to an RF front-end; and

a controller controlling said RF beam selection switch to in accordance with predetermined performance criteria.

2. A dual role antenna assembly as claimed in claim 1, wherein the gain patterns of said antenna are tilted in relation to the horizon with said antennas having optimum low elevation performance facing in different directions.

3. A dual role antenna assembly as claimed in claim 2, comprising at least two said antennas, and wherein said different directions for a pair of said antennas are diametrically opposed.

4. A dual role antenna assembly as claimed in claim 1, wherein the controller is programmed to give priority to GEO satellites.

5. A dual role antenna assembly as claimed in claim 1, wherein the controller is programmed to share the selected antenna with both GEO and LEO/MEO satellites in a half-duplex manner.

6. A dual role antenna assembly as claimed in claim 1, wherein the controller is programmed to use the selected antenna for both GEO satellites and the or one of the other antennas for LEO/MEO satellites.

7. A dual role antenna assembly as claimed in claim 1, further comprising a received signal strength monitor for providing a received signal strength indication, and wherein the predetermined performance criteria comprise the received signal strength indication.

8. A dual role antenna assembly as claimed in claim 7, wherein the received signal strength indication is based on signals received from a GEO satellite.

9. A dual role antenna assembly as claimed in claim 1, wherein said antennas are tunable between frequency sub-bands, and further comprising a frequency switch associated with each said antenna and operative to switch between the sub-bands.

10. A dual role antenna assembly as claimed in claim 9, wherein each said frequency switch is controlled by said controller.

11. A dual role antenna assembly as claimed in claim 9, wherein said antennas have multiple feed points corresponding to the different sub-bands.

12. A dual role antenna assembly as claimed in claim 9, wherein the ground plane lies on a printed circuit board, and each said frequency switch is mounted on the printed circuit board in close proximity to the antennas.

13. A dual role antenna assembly as claimed in claim 9, wherein said frequency switch associated with each said antenna is mounted inside a dielectric form forming part of said antenna.

14. A dual role antenna assembly as claimed in claim 1, wherein the height of the antenna is at least 12 mm.

15. A dual role antenna assembly as claimed in claim 1, wherein the curled inverted-F antenna is mounted on an elliptical dielectric form.

16. A method of controlling dual role antenna assembly operable for use with GEO and LEO/MEO satellites, comprising at least two curled inverted-F substantially omnidirectional antennas mounted on the ground plane, said antennas having asymmetrical gain patterns favoring certain sectors, and said antennas being oriented such that the favored sectors of the different antenna face different directions, said method comprising:

measuring a performance indication for each antenna; and

selecting as a primary antenna the antenna with the best performance indication.

17. A method as claimed in claim 16, wherein the primary antenna is shared with the GEO and LEO/MEO satellites in a half duplex manner.

18. A method as claimed in claim 16, wherein the other antenna is used for the LEO/MEO satellites.

19. A method as claimed in claim 16, wherein the performance indication is the received signal strength indication.

20. A method as claimed in claim 16, wherein the performance indication is the received signal strength indication of a GEO satellite.

21. A method as claimed in claim 16, wherein the antenna are tunable stepped across a frequency band.

22. A method as claimed in claim 21, wherein the antennas have multiple feed points, and different feed points are selected for different frequency sub-bands.

23. An antenna comprising:

a dielectric form of elliptical cross section; and

conductive strips peripherally mounted on said dielectric form to provide a curled inverted-F substantially omnidirectional antenna, said antenna having an asymmetrical gain pattern favoring certain sectors.

24. An antenna as claimed in claim 23, wherein said dielectric form has major and minor axis radii of 11 mm and 7 mm, respectively, and a height of 12 mm.

25. An antenna as claimed in claim 23, wherein said dielectric form is hollow.