Method and apparatus for frequency selective beam forming

• US 6,448,938 B1
• Filed: 06/12/2001
• Issued: 09/10/2002
• Est. Priority Date: 06/12/2001
• Status: Expired due to Term

• Current Assignee: IPR Licensing Incorporated (InterDigital, Inc.)
• Original Assignee: Tantivy Communications Incorporated (InterDigital, Inc.)
• Inventors: Chiang, Bing, Gainey, Kenneth M., Proctor, Jr., James A.
• Primary Examiner(s): Wong, Don
• Assistant Examiner(s): Clinger, James
• Application Number:
  US09/879,807
• Time in Patent Office: 455 Days
• Field of Search: 343/850, 343/814, 343/853, 343/700.MS, 342/372, 342/368, 342/432, 455/422
• US Class Current: 343/850
• CPC Class Codes: H01Q 1/246 specially adapted for base stations
• CPC Class Codes: H01Q 21/0018 Space- fed 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: H01Q 5/50 Feeding or matching arrangements for broad-band or multi-band operation
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/086 using weights depending on external parameters, e.g. direction of arrival [DOA], predetermined weights or beamforming

Abstract

A phased array antenna provides a subscriber unit with an ability to transmit and receive signals in different directions to allow for optimum gain in both directions, simultaneously. In this way, refraction and multipath effects resulting from communication signals operating at different frequencies can be compensated for to improve gain in both the forward and reverse links. Frequency selective components are coupled to respective antenna elements. At least two weighting structures are coupled to the frequency selective components to produce independently steerable beams having spectrally separated signals. The weighting structures may include phase shifting elements to steer the beams independently and include at least one variable gain amplifying component to independently amplify the signals received by or transmitted by the respective antenna, thereby optimizing the respective shapes of the beams. By having independently steerable and shapable beams, the directive antenna is attractive for use in a multi-band and/or multipath environment, same frequency or spread spectrum network.

Claims

1. A directive antenna, comprising:

plural antenna elements arranged in an antenna array;

frequency selective components each coupled to a respective antenna element; and

at least two weighting structures coupled to each of the frequency selective components to produce independently steerable beams having spectrally separated signals.

2. The directive antenna as claimed in claim 1, wherein the frequency selective components separate transmit and receive signals.

3. The directive antenna as claimed in claim 1, wherein the frequency selective components separate same direction signals having different frequencies.

4. The directive antenna as claimed in claim 1, wherein the frequency selective components are printed.

5. The directive antenna as claimed in claim 1, wherein the frequency selective components are non-printed.

6. The directive antenna as claimed in claim 1, wherein the weighting structures include phase shifting elements.

7. The directive antenna as claimed in claim 6, wherein the phase shifting elements receive independent control signals to set-up respective phase shifts.

8. The directive antenna as claimed in claim 1, wherein at least one of the weighting structures includes at least one variable gain amplifying component.

9. The directive antenna as claimed in claim 8, wherein the number of variable gain amplifying components associated with each antenna element corresponds to the number of spectrally separated beams being independently optimized in shape.

10. The directive antenna as claimed in claim 1, further including a combiner associated with each beam being produced to combine signals transmitted or received by the antenna elements.

11. The directive antenna as claimed in claim 1, simultaneously producing the beams.

12. The directive antenna as claimed in claim 1, used in a multipath environment.

13. The directive antenna as claimed in claim 1, used in one of the following networks:

same frequency network, spread spectrum network, code division multiple access (CDMA) network, or orthogonal frequency division multiplexing (OFDM) network.

14. The directive antenna as claimed in claim 1, wherein one of the weighting structures coupled to the frequency selective components is adjusted to optimize a receive beam pattern based on a received pilot signal.

15. The directive antenna as claimed in claim 1, wherein one of the weighting structures coupled to the frequency selective components is adjusted to optimize a transmit beam pattern based on a received signal quality of a given signal via a feedback metric over a forward link.

16. The directive antenna as claimed in claim 1, wherein one of the weighting structures coupled to the frequency selective components is adjusted to steer a transmit beam in the direction of maximum received power of a signal from a given base station, while another one of the weighting structures coupled to the frequency selective components is adjusted to optimize a receive beam based on a metric selected from the group consisting of a best signal-to-noise ratio (SNR) and carrier-to-interference (C/I) level.

17. A method for producing independently steerable beams, comprising:

weighting a first signal at a first frequency received by or to be transmitted by plural elements arranged in an antenna array having frequency selective components each coupled to a respective antenna element to produce a first steerable beam; and

weighting a second signal spectrally separated from the first signal to produce a second and independently steerable beam received by or to be transmitted by the same antenna array.

18. The method as claimed in claim 17, wherein weighting the first and second signals includes phase shifting the signals.

19. The method as claimed in claim 18, further including selecting the phase shift of the first and second signals, respectively.

20. The method as claimed in claim 17, wherein the first signal is transmitted by the antenna array and the second signal is received from the antenna array.

21. The method as claimed in claim 17, wherein weighting the first and second signals includes variably amplifying the signals to optimize the shapes of the beams.

22. The method as claimed in claim 17, wherein weighting of the first and second signals is performed simultaneously to produce the beams simultaneously.

23. The method as claimed in claim 17, used in a multipath environment.

24. The method as claimed in claim 17, used in one of the following networks:

same frequency network, spread spectrum network, code division multiple access (CDMA) network, or orthogonal frequency division multiplexing (OFDM) network.

25. The method as claimed in claim 17, further including optimizing a receive beam pattern based on a received pilot signal.

26. The method as claimed in claim 17, further including optimizing a transmit beam pattern based on a received signal quality of a given signal via a feedback metric over a forward link.

27. The method as claimed in claim 17, further including steering a transmit beam in the direction of maximum received power of a signal from a given base station, while optimizing a receive beam based on a metric selected from the group consisting of a best signal-to-noise ratio (SNR) and carrier-to-interference (C/I) level.

28. Apparatus for beam forming, comprising:

means for phase shifting a first signal at a first frequency received by or to be transmitted by plural antenna elements arranged in an antenna array, having frequency selective components each coupled to a respective antenna element, to produce a first steerable beam; and

means for phase shifting a second signal spectrally separated from the first signal to produce a second and independently steerable beam received by or to be transmitted by the same antenna array.