Beamformer for multi-beam receive antenna

• US 6,784,838 B2
• Filed: 11/08/2002
• Issued: 08/31/2004
• Est. Priority Date: 11/09/2001
• Status: Expired due to Term

• Current Assignee: EMS Technologies, Inc. (Honeywell International Inc.)
• Original Assignee: EMS Technologies, Inc. (Honeywell International Inc.)
• Inventors: Howell, James M.
• Primary Examiner(s): Issing, Gregory C.
• Application Number:
  US10/290,996
• Publication Number:
  US 20030095067A1
• Time in Patent Office: 662 Days
• Field of Search: 342/371, 342/372, 342/373, 342/377, 455/562.1
• US Class Current: 342/377
• CPC Class Codes: H01Q 21/061 Two dimensional planar arrays
• CPC Class Codes: H01Q 25/00 Antennas or antenna systems providing at least two radiating patterns arrangements for changing or varying the orientation or the shape of the directional pattern H01Q3/00
• CPC Class Codes: H01Q 3/26 varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture H01Q3/12, H01Q3/22, H01Q3/24 take precedence
• CPC Class Codes: H04B 7/0837 using pre-detection combining H04B7/0868 takes precedence

Abstract

A phased array antenna system that is operative to simultaneously form multiple beams without requiring an undue amount of hardware. The system collects propagating energy with a number of antenna elements to form multiple beams, encodes the beams as the energy is collected, combines the encoded beams, and then decodes the combined signal to separate the beams. In this way, the beams can be formed with a single set of antenna hardware instead of requiring a multiplicity of antenna hardware, one for each beam. Frequency coding may be implemented by repeatedly applying a Doppler phase shift to each beam, and then using a Doppler filter to separate the beams. Alternatively, a code division multiplexing technique may be implemented by using a CDMA code generator to apply a code to each beam, and then using a CDMA filter to separate the beams.

Claims

1. A method for operating a phased array antenna system, comprising the steps of:

receiving propagating energy at multiple antenna elements;

setting control signals for forming the received energy into multiple beams;

embedding coding parameters into the control signals;

applying the encoded control signals to at least one phase and gain control device associated with each antenna element to form multiple encoded beams;

combining the encoded beams into a combined signal; and

decoding the combined signal to separate the beams.

2. The method of claim 1, further comprising a step selected from the group consisting of further processing, displaying or recording a representation of each beam separately.

3. The method of claim 1 repeated for a plurality of desired beam sets.

4. The method of claim 1, in which the control signal for each antenna element is applied to a single phase and gain control device dedicated to the corresponding antenna element.

5. The method of claim 1, in which each antenna element includes a plurality of phase end gain control devices, with one phase and gain control device dedicated to each beam, and the control signal for each antenna element is applied to the plurality of phase and gain control devices associated with the corresponding antenna element, such that a control signal component for each beam is applied to a corresponding phase and gain control device.

6. The method of claim 1, in which the encoded beams are combined in a single beam forming combiner.

7. The method of claim 1, wherein:

the step of forming the received energy into multiple beams comprises defining a control signal for each antenna element, in which each control signal comprises a beam component corresponding to each beam;

the step of encoding the beams comprises embedding a coding parameter into each beam component identifying the corresponding beam, in which the coding parameter for a corresponding beam is the same for each antenna element; and

the step of decoding the combined signal to separate the beams comprises detecting the coding parameters and combining the beam components from each antenna element having similar coding parameters.

8. The method of claim 7, wherein the step of combining the encoded beams into a combined signal comprises the steps of:

computing an in-phase component for the control signal for each antenna element comprising a sum of in-phase beam components for the corresponding antenna element;

computing a quadrature component for the control signal for each antenna element comprising a sum of quadrature beam components for the corresponding antenna element; and

computing a total gain and a total phase shift for each antenna element from the corresponding in-phase and quadrature components.

9. The method claim 8, wherein:

the in-phase beam components for each antenna element include an in-phase component corresponding to each beam; and

the quadrature beam components for each antenna element include an in-phase component corresponding to each beam.

10. The method of claim 1, wherein:

the beams are encoded with frequencies by repeatedly incrementing phase shifts embedded in the control signals; and

the beams are decoded with a frequency filter.

11. The method of claim 9, wherein the step of encoding the beams comprises embedding a coding parameter into the in-phase and quadrature beam components, in which the coding parameter for a corresponding beam is the same for each antenna element.

12. The method of claim 11, wherein:

the beams are encoded by embedding repeatedly incrementing phase shifts embedded into the in-phase and quadrature beam components; and

the beams are decoded with a frequency filter.

13. The method of claim 1, wherein the beams are encoded with orthogonal codes and decoded with an orthogonal code filter.

14. The method of claim 11, wherein:

the beams are encoded by embedding orthogonal codes into the in-phase and quadrature beam components; and

the beams are decoded with an orthogonal code filter.

15. A computer storage medium comprising computer executable instructions for performing the method of claim 1.

16. An apparatus configured to perform the method of claim 1.

17. A computer storage medium comprising computer executable instructions for performing the method of claim 11.

18. An apparatus configured to perform the method of claim 11.

19. A multi-beam phased array antenna system comprising:

a plurality of antenna elements;

one or more phase and gain control devices associated with each antenna element;

a beam forming combiner creating a combined signal from signals received from the antenna elements;

a beam forming computer configured to generate control signals to drive the phase and gain control devices to create multiple beams, in which each beam is identified by a coding parameter embedded in the control signals; and

a filter configured to receive the combined signal, detect the coding parameters, and separate the beams using the coding parameters.

20. The antenna system of claim 19, comprising a single phase and gain control device associated with each antenna element.

21. The antenna system of claim 20, wherein:

the control signal for each antenna element comprises a beam component corresponding to each beam;

the coding parameter for a corresponding beam is the same for each antenna element; and

the beams are separated by detecting the coding parameters and combining the beam components from each antenna element having similar coding parameters.

22. The antenna system of claim 21, wherein:

the control signal for each antenna element comprises an in-phase component defined by a sum of in-phase beam components for the corresponding antenna element;

the control signal for each antenna element comprises a quadrature component defined by a sum of quadrature beam components for the corresponding antenna element; and

the control signal for each antenna element comprises a total gain and a total phase shift for the antenna element based on the in-phase and quadrature components for the corresponding antenna element.

23. The antenna system of claim 22, wherein:

the in-phase beam components for each antenna element include an in-phase component corresponding to each beam; and

the quadrature beam components for each antenna element include an in-phase component corresponding to each beam.

24. The antenna system of claim 23, wherein the coding parameters are embedded into the in-phase and quadrature beam components.

25. The antenna system of claim 24, wherein:

the coding parameters represent frequencies; and

the filter is a frequency filter.

26. The antenna system of claim 24 wherein:

the coding parameters are orthogonal codes; and

the beams are decoded with an orthogonal code filter.

27. The antenna system of claim 24, further comprising a beam selector configured to identify desired beam sets, and wherein the beam forming computer is configured to generate control signals to drive the phase and gain control devices to create multiple beams for each desired beam set.

28. The antenna system of claim 24, further comprising a code selector configured to identify desired coding parameter sets, and wherein the beam forming computer is configured to generate control signals to drive the phase and gain control devices to create multiple beams for each desired coding parameter set.

29. The antenna system of claim 28, wherein the coding parameter sets include orthogonal coding and frequency coding code sets.

30. A multi-beam phased array antenna system comprising:

a plurality of antenna elements;

a phase and gain control device for each antenna element;

a beam forming combiner creating a combined signal from the signals received from the antenna elements;

a code selector configured to identify desired coding parameter sets,

a beam selector configured to identify desired beam sets;

a beam forming computer configured to generate control signals to drive the phase and gain control devices to create the multiple beams for a desired beam set, in which each beam is identified by a coding parameter embedded into the control signal using a desired code set; and

a filter configured to receive the combined signal, detect the coding parameters, and separate the beams using the coding parameters.

31. The antenna system of claim 30, wherein:

the control signal for each antenna element comprises a beam component corresponding to each beam;

the coding parameter for a corresponding beam is the same for each antenna element; and

the beams are separated by detecting the coding parameters and combining the beam components from each antenna element having similar coding parameters.

32. The antenna system of claim 31, wherein:

the control signal for each antenna element comprises an in-phase component defined by a sum of in-phase beam components for the corresponding antenna element and a quadrature component defined by a sum of quadrature beam components for the corresponding antenna element;

the coding parameters are embedded into the in-phase and quadrature beam components, and

the control signal for each antenna element comprises a total gain and a total phase shift for the antenna element based on the in-phase and quadrature components for the corresponding antenna element.

33. The antenna system of claim 32, wherein the coding parameter sets include orthogonal coding and frequency coding code sets.

34. In a beam former of the type for use with a phased array antenna system comprising multiple antenna elements, an improvement comprising:

a beam former operative for receiving propagating energy at multiple antenna elements, setting control signals for forming the received energy into multiple beams, embedding coding parameters into the control signals, applying the encoded control signals to at least one phase and gain control device associated with each antenna element to form multiple encoded beams, combining the coded beams into a combined signal, and decoding the combined signal to separate the beams.

35. An antenna system comprising:

a plurality of antenna elements;

a beam former operative for setting control signals for forming the received energy into multiple separate beams, embedding coding parameters into the control signals, and applying the encoded control signals to at least one phase and gain control device associated with each antenna element to form multiple encoded beams;

a combiner for combining the multiple encoded beams into a combined signal; and

a decoder for recovering the separate beams from the combined signal.