ARRAY ANTENNA AND A METHOD OF DETERMINING AN ANTENNA BEAM ATTRIBUTE

• US 20080252522A1
• Filed: 04/13/2007
• Published: 10/16/2008
• Est. Priority Date: 04/13/2007
• Status: Active Grant

• Current Assignee: CommScope Technologies, LLC (CommScope Holding Company, Inc.)
• Original Assignee: Andrew LLC (CommScope Holding Company, Inc.)
• Inventors: Asbridge, Harold E.
• Granted Patent: US 7,830,307 B2
• Time in Patent Office: Days
• US Class Current: 342/368
• CPC Class Codes: H01Q 21/061 Two dimensional planar arrays
• CPC Class Codes: H01Q 21/08 the units being spaced along or adjacent to a rectilinear path waveguide fed H01Q21/0037

Abstract

A method of determining one or more attribute of an antenna beam based on measuring phase and/or amplitude differences at different points in a feed network. By using lookup tables based on actual measurements of antenna beam attributes for phase and/or amplitude differences at different points in a feed network computation may be simplified. The method enables a relatively inexpensive control circuit to be employed while providing accurate measurement of antenna beam attributes.

Claims

1. A method of determining an attribute of a beam of an array antenna having a plurality of radiating elements fed by a feed network including one or more variable elements comprising:

a. measuring at least one of a phase and amplitude difference between signals at a plurality of points in the feed network, less than the number of radiating elements, sufficient to characterize an attribute of a beam of the antenna; and

b. determining an attribute value of the beam of the antenna based on the measured difference.

2. A method as claimed in claim 1 wherein measuring at least one of the phase and amplitude difference comprises measuring at least one of the phase and amplitude differences between an input signal to and an output signal from a variable element.

3. A method as claimed in claim 1 wherein measuring at least one of the phase and amplitude difference comprises measuring at least one of the phase and amplitude difference between output signals of a subset of variable phase shifters sufficient to characterize an attribute of a beam of the antenna.

4. A method as claimed in claim 1 wherein an attribute value of the beam of the antenna is determined by finding a beam attribute value in a lookup table corresponding to the one or more measured differences.

5. A method as claimed in claim 4 wherein the attribute values in the lookup table are based on measured attributes of the antenna for measured differences at points in the feed network.

6. A method as claimed in claim 4 wherein the attribute values in the lookup table are based on one or more algorithm relating measured differences at points in the feed network to antenna attributes.

7. A method as claimed in claim 1 wherein the attribute is beam shape.

8. A method as claimed in claim 1 wherein the attribute is beam orientation.

9. A method as claimed in claim 1 wherein the attribute is beam down tilt.

10. A method as claimed in claim 1 wherein the attribute is beam azimuth.

11. A method as claimed in claim 1 wherein the attribute is beam width.

12. A method as claimed in claim 1 wherein one or more actuators is driven to adjust one or more variable elements of the feed network until the determined attribute value corresponds to a desired attribute value.

13. A method as claimed in claim 12 wherein the variable elements are passive elements.

14. A method as claimed in claim 12 wherein the one or more actuators is an electromechanical actuator.

15. A method as claimed in claim 12 wherein the one or more variable elements are phase shifters.

16. A method as claimed in claim 12 wherein the variable elements are driven asymmetrically.

17. A method as claimed in claim 12 wherein the variable elements are driven independently.

18. A method as claimed in claim 12 wherein control is effected by a controller within the antenna.

19. A method as claimed in claim 12 wherein data relating to measured signal values is communicated to a remote controller which generates drive signals to control the variable elements.

20. An array antenna comprising:

a. a plurality of radiating elements;

b. a feed network including one or more variable element feeding the radiating elements;

c. a plurality of probes, less than the number of radiating elements, including at least;

i. a first probe configured to sense a signal at a first point in the feed network; and

ii. a second probe configured to sense a signal at a second point in the feed network; and

d. a control circuit configured to receive signals from the at least first probe and second probe and to generate an antenna attribute signal based on one or more difference between the signals sensed by the at least first probe and second probe.

21. An array antenna as claimed in claim 20 wherein the first probe senses an input signal to one of the one or more variable elements and the second probe senses an output signal from one of the one or more variable elements.

22. An array antenna as claimed in claim 20 wherein the first probe and second probe sense output signals of the feed network.

23. An array antenna as claimed in claim 20 wherein the control circuit includes a lookup table relating probe signals to attribute values.

24. An array antenna as claimed in claim 23 wherein the attribute values are based on measured attributes of the array antenna beam over a range of probe signal values.

25. An array antenna as claimed in claim 23 wherein the control circuit calculates intermediate attribute values by interpolation.

26. An array antenna as claimed in claim 23 wherein attribute values are calculated for measured probe signals according to one or more algorithm.

27. An array antenna as claimed in claim 23 wherein the lookup table is non-volatile memory.

28. An array antenna as claimed in claim 20 wherein the control circuit includes one or more magnitude and phase detectors.

29. An array antenna as claimed in claim 28 wherein the magnitude and phase detector receives signals from two probes.

30. An array antenna as claimed in claim 20 including one or more actuator configured to drive the one or more variable elements in dependence upon the signals sensed by the probes.

31. An array antenna as claimed in claim 30 wherein the one or more variable elements are passive elements.

32. An array antenna as claimed in claim 31 wherein the one or more variable elements are phase shifters.

33. An array antenna as claimed in claim 30 wherein the one or more actuators are electromechanical actuators.

34. An array antenna as claimed in claim 30 wherein the control circuit controls the one or more actuators based on the antenna attribute signal and a demand signal.

35. An array antenna as claimed in claim 34 wherein the demand signal is stored in the control circuit.

36. An array antenna as claimed in claim 34 wherein the demand signal is received via a communication port of the control circuit.

37. An array antenna as claimed in claim 36 wherein the demand signal is received via a serial port.

38. An array antenna as claimed in claim 36 wherein the demand signal is received via a wireless link.

39. An array antenna as claimed in claim 36 wherein the demand signal is received via a feed line supplying RF signals to the feed network.

40. A system comprising a plurality of array antennas as claimed in claim 20 and a central controller wherein the array antennas are configured to communicate antenna attribute signals to the central controller and to receive demand signals from the central controller.