Diversity Antenna System with Electrical Tilt

• US 20090066595A1
• Filed: 08/10/2007
• Published: 03/12/2009
• Est. Priority Date: 08/18/2006
• Status: Active Grant

• Current Assignee: Quintel Cayman Limited
• Original Assignee: Quintel Technology Limited (Cirtek Holdings Philippines Corp.)
• Inventors: Newbold, Stephen Thomas, Haskell, Philip Edward, Thomas, Louis David, Barker, David Edwin
• Granted Patent: US 8,269,668 B2
• Time in Patent Office: Days
• US Class Current: 343/757
• CPC Class Codes: H01Q 1/246 specially adapted for base stations
• 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: H04B 7/10 Polarisation diversity; Directional diversity

Abstract

A diversity antenna system with electrical tilt has two dual polarised, tilt adjustable antenna stacks (44A) and (44B) with physical separation providing space diversity. Each antenna stack (44A) or (44B) has two polarisations associated with independently adjustable electrical tilt angles. The electrical tilt angles of each antenna stack (44A) or (44B) are controlled to be equal to those of the other antenna stack to provide co-polarisation or anti-polarisation tilt coupling. The antenna system (40) may operate with multiple carrier frequencies each associated with a respective pair of polarisations of different antenna stacks (44A) and (44B) with co-polarisation or anti-polarisation tilt coupling. Antenna tilt angles are controllable so that different carrier frequencies are associated with independently adjustable angles of electrical tilt. The system may be used with groups of both contiguous and non-contiguous carrier frequencies.

Claims

1. An antenna system having two dual polarised, tilt adjustable antennas with physical separation providing space diversity, and wherein:

a) each antenna has polarisations associated with respective independently adjustable electrical tilt angles; and

b) each antenna has electrical tilt angles which are controllable to be equal to those of the other antenna and to provide one of co-polarisation tilt coupling and anti-polarisation tilt coupling.

2. An antenna system according to claim 1 for operation with at least one first carrier frequency associated with one pair of antenna polarisations having one of co-polarisation tilt coupling and anti-polarisation tilt coupling and at least one second carrier frequency associated with another pair of antenna polarisations having one of anti-polarisation tilt coupling and co-polarisation tilt coupling respectively, the antenna tilt angles being controllable to provide for the at least one first carrier frequency and the at least one second carrier frequency to be associated with different angles of electrical tilt.

3. An antenna system according to claim 2 wherein the at least one first carrier frequency and the at least one second carrier frequency are first and second groups of carrier frequencies respectively.

4. An antenna system according to claim 2 wherein the at least one first carrier frequency and the at least one second carrier frequency are associated with one of multiple operators, multiple base stations and multiple cellular standards.

5. An antenna system according to claim 1 including two feeders to convey signals between base station equipment and antennas.

6. An antenna system according to claim 1 including three feeders for conveying signals between base station equipment and antennas, one of the feeders being for receive signals only, the receive signals being associated both with different antennas and with different antenna polarisations.

7. An antenna system according to claim 1 including four feeders for conveying signals between base station equipment and antennas, two of the feeders being for receive signals only and associated both with different antennas and with different antenna polarisations.

8. An antenna system according to claim 7 including broad band filtering means co-located with antennas in antenna assemblies and narrow band filtering means co-located with base station equipment.

9. An antenna system according to claim 1 including four feeders for conveying transmit and receive signals between base station equipment and antennas, two of the feeders being associated with different polarisations of one of the antennas, and another two of the feeders being associated with different polarisations of the other of the antennas.

10. An antenna system according to claim 9 including narrow band filtering means co-located with antennas in antenna assemblies.

11. An antenna system according to claim 1 including four feeders for conveying signals between base station equipment and the antennas designated as first and second antennas, two of the feeders being for first and second transmit signals associated respectively with a first polarisation of the first antenna and a second polarisation of the second antenna, another of the feeders being for receive signals also associated respectively with the first polarisation of the first antenna and the second polarisation of the second antenna, and a fourth one of the feeders being for receive signals associated respectively with the second polarisation of the first antenna and the first polarisation of the second antenna.

12. An antenna system according to claim 1 wherein each polarisation of each antenna is associated with a respective broad band filtering means, a respective feeder and a respective narrow band filtering means.

13. An antenna system according to claim 12 wherein each broad band filtering means is located in an antenna assembly and is connected by the respective feeder to the respective narrow band filtering means co-located with base station equipment.

14. An antenna system according to claim 13 wherein the narrow band filtering means is arranged to divide signals with contiguous frequencies into groups of signals with non-contiguous frequencies.

15. An antenna system according to claim 1 including filtering means for defining signals of like frequency associated with different antennas and providing space diversity in at least one of transmit and receive modes of operation.

16. An antenna system according to claim 1 wherein one antenna has antenna elements arranged for transmission of a first frequency transmit signal and the other antenna has antenna elements arranged for transmission of a first frequency space diversity transmit signal.

17. An antenna system according to claim 1 arranged to provide for one receive signal to be associated with multiple receive diversity signals.

18. A method of operating an antenna system having two dual polarised, tilt adjustable antennas with physical separation providing space diversity, the method including:

a) adjusting electrical tilt angles of each antenna'"'"'s polarisations independently; and

b) controlling each antenna'"'"'s electrical tilt angles to be equal to those of the other antenna to provide one of co-polarisation tilt coupling and anti-polarisation tilt coupling.

19. A method according to claim 18 including operating with at least one first carrier frequency associated with one pair of antenna polarisations having one of co-polarisation tilt coupling and anti-polarisation tilt coupling and at least one second carrier frequency associated with another pair of antenna polarisations having one of anti-polarisation tilt coupling and co-polarisation tilt coupling respectively, and controlling the antenna tilt angles to provide for the at least one first carrier frequency and the at least one second carrier frequency to be associated with different angles of electrical tilt.

20. A method according to claim 18 wherein the at least one first carrier frequency and the at least one second carrier frequency are first and second groups of carrier frequencies respectively.

21. A method according to claim 18 wherein the at least one first carrier frequency and the at least one second carrier frequency are associated with one of multiple operators, multiple base stations and multiple cellular standards.

22. A method according to claim 18 including conveying signals between base station equipment and the antennas using two feeders.

23. A method according to claim 18 including conveying signals between base station equipment and the antennas using three feeders, using one of the feeders for receive signals only, the receive signals being associated both with different antennas and with different antenna polarisations.

24. A method according to claim 18 including conveying signals between base station equipment and the antennas using four feeders, using two of the feeders for receive signals only, the receive signals being associated both with different antennas and with different antenna polarisations.

25. A method according to claim 24 including broad band filtering with filtering means co-located with the antennas in antenna assemblies and narrow band filtering with filtering means co-located with base station equipment.

26. A method according to claim 18 including conveying transmit and receive signals between base station equipment and the antennas using four feeders, two of the feeders being associated with different polarisations of one of the antennas, and another two of the feeders being associated with different polarisations of the other of the antennas.

27. A method according to claim 26 including narrow band filtering with filtering means co-located with the antennas in antenna assemblies.

28. A method according to claim 18 including using four feeders for conveying signals between base station equipment and the antennas designated as first and second antennas, using two of the feeders for first and second transmit signals associated respectively with a first polarisation of the first antenna and a second polarisation of the second antenna, using another of the feeders for receive signals also associated respectively with the first polarisation of the first antenna and the second polarisation of the second antenna, and using a fourth one of the feeders for receive signals associated respectively with the second polarisation of the first antenna and the first polarisation of the second antenna.

29. A method according to claim 18 wherein each polarisation of each antenna is associated with broad band filtering, a respective feeder and narrow band filtering.

30. A method according to claim 29 wherein the broad band filtering is implemented in an antenna assembly and the narrow band filtering is implemented by means co-located with base station equipment.

31. A method according to claim 30 including using the narrow band filtering means to divide signals with contiguous frequencies into groups of signals with non-contiguous frequencies.

32. A method according to claim 18 including filtering to define signals of like frequency associated with different antennas and provide space diversity in at least one of transmit and receive modes of operation.

33. A method according to claim 18 wherein one antenna has antenna elements arranged for transmission of a first frequency transmit signal and the other antenna has antenna elements arranged for transmission of a first frequency space diversity transmit signal.

34. A method according to claim 18 including providing for one receive signal to be associated with multiple receive diversity signals.