Smart reflection antenna system and method

• US 6,509,836 B1
• Filed: 04/02/2001
• Issued: 01/21/2003
• Est. Priority Date: 03/31/2000
• Status: Expired due to Fees

• Current Assignee: Georgia Tech Research Corporation (University System of Georgia)
• Original Assignee: Georgia Tech Research Corporation (University System of Georgia)
• Inventors: Ingram, Mary A.
• Primary Examiner(s): TRIEU, VAN THANH
• Application Number:
  US09/824,317
• Time in Patent Office: 659 Days
• Field of Search: 340/572.4, 340/572.7, 340/572.8, 340/573.1, 340/10.1, 340/10.2, 340/10.3, 340/10.42, 340/10.6, 342/42, 342/44, 342/51, 342/367, 455/277.1, 455/100, 455/101, 343/850, 343/872, 310/313.R
• US Class Current: 340/572.4
• CPC Class Codes: G01S 13/758 using a signal generator powered by the interrogation signal
• CPC Class Codes: G01S 13/767 Responders; Transponders teaching or practice apparatus for gun-aiming or gun-laying using reflecting targets or active targets F41G3/26
• CPC Class Codes: G01S 13/825 with exchange of information between interrogator and responder
• CPC Class Codes: G06K 19/07767 the first and second communication means being two different antennas types, e.g. dipole and coil type, or two antennas of the same kind but operating at different frequencies
• CPC Class Codes: G06K 19/07779 the inductive antenna being a coil
• CPC Class Codes: G06K 19/07783 the coil being planar
• CPC Class Codes: G06K 19/07784 the inductive antenna consisting of a plurality of coils stacked on top of one another
• CPC Class Codes: G06K 7/10346 the antenna being of the far field type, e.g. HF types or dipoles

Abstract

A smart reflection antenna system and method are disclosed. In this regard, a representative embodiment of a smart reflection antenna system includes an interrogator transmitter (IT) having an IT array of at least two antennas, the IT being configured to simultaneously transmit a carrier signal from multiple antennas of the IT array. The system also includes a tag having a tag array of at least one antenna. The tag being configured to simultaneously receive the carrier signal from the IT array via the tag array, modulate the carrier signal into a modulated carrier signal; and simultaneously transmit the modulated carrier signal via the tag array. The system also includes an interrogator receiver (IR) having an IR array of at least two antennas, the IR being configured to simultaneously receive the modulated carrier signal from the tag array via multiple antennas of the IR array. Other embodiments of systems and methods are disclosed.

Claims

1. A smart reflection antenna system comprising:

an interrogator transmitter (IT) having an IT array of at least two antennas, the IT being configured to simultaneously transmit a carrier signal from multiple antennas of the IT array;

a tag having a tag array of at least one antenna, the tag being configured to;

simultaneously receive the carrier signal from the IT array via the tag array;

modulate the carrier signal into a modulated carrier signal; and

simultaneously transmit the modulated carrier signal via the tag array; and

an interrogator receiver (IR) having an IR array of at least two antennas, the IR being configured to simultaneously receive the modulated carrier signal from the tag array via multiple antennas of the IR array.

2. The smart reflection antenna system as defined in claim 1, wherein a computing device determines the information regarding a channel between the IT array and the IR array, after the IR array receives the modulated carrier signal.

3. The smart reflection antenna system as defined in claim 2, wherein the IR array is further configured to communicate the information to the IT array.

4. The smart reflection antenna system as defined in claim 3, wherein the computing device uses the information to control weights of the antennas in the IT array to produce a distorted phase front to enhance characteristics of the modulated carrier signal.

5. The smart reflection antenna system as defined in claim 1, wherein the tag array is divided into at least two groups, wherein each group has at least one antenna.

6. The smart reflection antenna system as defined in claim 5, wherein each group uses different data streams to modulate the carrier signal.

7. The smart reflection antenna system as defined in claim 5, wherein each group uses the different data streams and different modulation techniques to modulate the carrier signal.

8. The smart reflection antenna system as defined in claim 7, wherein the modulation techniques is a group consisting of code-division multiplexing (CDM), or frequency division multiplexing (FDM).

9. The system of claim 1, wherein the tag is further configured to simultaneously receive the carrier signal from multiple antennas of the IT array via multiple antennas of the tag array;

and

wherein the IR is further configured to simultaneously receive the modulated carrier signal from multiple antennas of the tag array via multiple antennas of the IR array.

10. The system of claim 1, wherein the at least one antenna of the tag array is a reflective antenna.

11. A smart reflection antenna system comprising:

an interrogator transmitter (IT) having an IT array of at least two antennas, the IT being configured to simultaneously transmit a carrier signal from multiple antennas of the IT array;

a tag having a tag array of at least one antenna, the tag being configured to;

simultaneously receive the carrier signal from the IT array via the tag array;

modulate the carrier signal into a modulated carrier signal; and

simultaneously transmit the modulated carrier signal via the tag array; and

an interrogator receiver (IR) having an IR array of at least two antennas, the IR being configured to simultaneously receive the modulated carrier signal from the tag array via multiple antennas of the IR array; and

a communication link connecting the IR array to the IT array.

12. The smart reflection antenna system as defined in claim 11, wherein the communication link is a wired connection.

13. The smart reflection antenna system as defined in claim 11, wherein a computing device determines information regarding a channel between the IT array and the IR array, after the IR array receives the modulated carrier signal.

14. The smart reflection antenna system as defined in claim 13, wherein the IR array communicates the information to the IT array, via the communication link.

15. The smart reflection antenna system of claim 11, wherein the communication link is a wireless connection.

16. A method for improving the characteristics of a modulated carrier signal, the method comprising the steps of:

determining a product channel matrix between an interrogator transmitter (IT) antenna array and an interrogator receiver (IR) antenna array, wherein the product channel matrix is the product of a matrix of complex channel gains between the IT antenna array and a tag antenna array and a matrix of complex sideband channel gains between the tag antenna array and the IR antenna array;

calculating antenna weight vectors for the IT antenna array and the IR antenna array from the product channel matrix; and

controlling the weights of antennas of the IT antenna array with the calculated antenna weight vectors, such that the signal-to-noise ratio (SNR) is maximized for the modulated carrier signal.

17. The method of claim 16, wherein the modulated carrier signal is a carrier signal that is transmitted from the IT array, modulated backscattered and transmitted to the IR array.

18. The method of claim 16, wherein determining the product channel matrix comprises the step of identifying elements of the product channel matrix.

19. The method of claim 18, wherein identifying elements comprises the steps of:

sending test signals from each antenna of the IT antenna array; and

measuring the responses of the test signals at each antenna of the IR antenna array.

20. The method of claim 16, wherein calculating antenna weight vectors comprises the step of performing a singular value decomposition on the product channel matrix.

21. The method of claim 16, wherein upon controlling the weights of the IT antenna array, a distorted phase front is produced.

22. The method of claim 16, further comprising the step of:

controlling the weights of antennas of the IR antenna array with the calculated antenna weight vectors.

23. The method of claim 16, wherein the tag antenna array comprises at least two groups of antennas, and wherein the steps of determining a product channel matrix, calculating antenna weight vectors, and controlling the weights are performed for each group of antennas.

24. The method of claim 23, further comprising the steps of:

normalizing each weight vector to unit norm;

generating a final matrix from the normalized weight vectors; and

calculating final antenna weight vectors for the IT antenna array and the IR antenna array from the final matrix.

25. The method of claim 23, wherein each group of antennas of the tag array utilizes a different modulation technique to modulate a carrier signal.

26. The method of claim 23, wherein each group of antennas of the tag array utilizes different data streams to modulate a carrier signal.

27. A smart reflection antenna system comprising:

means for simultaneously transmitting a carrier signal to a tag from multiple antennas;

means for simultaneously receiving the carrier signal from an interrogator transmitter (IT);

means for modulating the carrier signal into a modulated carrier signal;

means for simultaneously transmitting the modulated carrier signal to an interrogator receiver (IR); and

means for simultaneously receiving the modulated carrier signal from the tag via multiple antennas of the IR.

28. The system of claim 27, further comprising means for determining information regarding a communication channel between the IT and the IR.

29. The system of claim 28, wherein the means for determining comprises:

means for determining a product channel matrix between an IT antenna array of the IT and an IR antenna array of the IR, wherein the product channel matrix is the product of a matrix of complex channel gains between the IT antenna array and a tag antenna array of the tag and a matrix of complex sideband channel gains between the tag antenna array and the IR antenna array; and

means for calculating antenna weight vectors for the IT antenna array and the IR antenna array from the product channel matrix.

30. The system of claim 29, further comprising means for controlling the weights of antennas of the IT antenna array with the calculated antenna weight vectors, such that the signal-to-noise ratio (SNR) is maximized for the modulated carrier signal.

31. The system of claim 28, further comprising means for communicating the information between the IT and the IR.

32. The system of claim 27, wherein the modulated carrier signal is a carrier signal that is transmitted from the IT, backscatter modulated, and transmitted to the IR.