Surface acoustic wave transponder configuration

• US 6,208,062 B1
• Filed: 02/10/1999
• Issued: 03/27/2001
• Est. Priority Date: 08/18/1997
• Status: Expired due to Term

• Current Assignee: X-Cyte Inc.
• Original Assignee: X-Cyte Inc.
• Inventors: Nysen, Paul A., Skeie, Halvor
• Primary Examiner(s): Dougherty, Thomas M.
• Application Number:
  US09/248,024
• Time in Patent Office: 776 Days
• Field of Search: 310/313.R, 333/152, 333/153, 333/156, 333/138
• US Class Current: 310/313.00R
• CPC Class Codes: G01S 13/343 using sawtooth modulation
• CPC Class Codes: G01S 13/755 using delay lines, e.g. acoustic delay lines
• CPC Class Codes: G06K 19/0672 with resonating marks
• CPC Class Codes: G06K 19/0675 the resonating marks being of the surface acoustic wave [SAW] kind SAW devices per se H03H9/64
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: H03H 9/02795 Multi-strip couplers as track changers
• CPC Class Codes: H03H 9/44 Frequency dependent delay lines, e.g. dispersive delay lines
• CPC Class Codes: H03H 9/6406 Filters characterised by a particular frequency characteristic

Abstract

An acoustic wave identification transponder device, having a substrate, an electroacoustic transducer generating an acoustic wave in said substrate and a set of encoding elements disposed in a path of the acoustic wave for modifying the acoustic wave, having elements which reflect portions of the acoustic wave having a component orthogonal to the incident wave. The reflectors may be, for example, trackchangers or reflective arrays compressors (RAC). The wave may be phase-amplitude modulated for increased efficiency expressed in bits per tap. Such phase amplitude modulation is preferably imposed by partial beam width phase delay elements disposed within an acoustic beam path.

Claims

1. A method of modulating an acoustic beam having a beamwidth, comprising the steps of selectively providing, along a path of the acoustic beam, one or more non-transducing elements which impose a phase delay on the acoustic wave, wherein at least a portion of elements are disposed over only a portion of the beamwidth, resulting in phase interference modulation of the acoustic beam.

2. The method according to claim 1, wherein said one or more elements comprises a set of members disposed bilaterally symmetrical with respect to an axis of acoustic beam propagation.

3. The method according to claim 1, wherein at least a subset of said elements modulate the acoustic beam in a QAM constellation pattern, wherein said QAM constellation pattern has about 2ⁿ states, and wherein n is an integer greater than or equal to 2.

4. The method according to claim 1, further comprising the step of equalizing a phase delay of portions of said acoustic beam across the width of the acoustic beam after passing said elements and prior to any transducing of the entire acoustic wave into an electrical signal.

5. The method according to claim 1, further comprising the step of splitting the acoustic beam after passing said elements and subjecting a portion of said split beam to a further set of elements for modulating said acoustic beam.

6. The method according to claim 5, wherein said further set of elements includes structures or equalizing a relative phase delay across the beamwidth and imposing a further net phase delay to at least a portion of the acoustic wave.

7. A method of modulating an acoustic wave, comprising generating an acoustic wave on a substrate, said acoustic wave propagating along a propagation axis and having a beam width along an axis perpendicular to the propagation axis, providing a phase delay pad disposed along the propagation axis within the beam width, occupying less than the entire beam width;

summing the acoustic power of the acoustic beam after interaction with the phase delay pad; and

outputting the summed acoustic power.

8. The method according to claim 7, further comprising the steps of, before said summing step, splitting the energy of the acoustic beam, equalizing a phase delay of respective portions of the beam width, providing an additional phase delay pad disposed along the propagation axis within the equalized beam width, occupying less than the entire equalized beam width;

and summing the acoustic power of the equalized acoustic beam after interaction with the additional phase delay pad, said outputting the summed acoustic power step comprising outputting a split portion of the acoustic beam and outputting the summed acoustic power of the equalized acoustic beam.

9. A device for modulating an acoustic beam having a beamwidth, comprising:

one or more non-transducing elements disposed along a predetermined path of an acoustic beam on a substrate, said elements being adapted for imposing a phase delay on the acoustic wave, wherein at least a portion of said elements are disposed over only a portion of the beamwidth, resulting in phase interference modulation of the acoustic beam.

10. The device according to claim 9, wherein said element comprises a set of members disposed symmetrical with respect to an axis of acoustic beam propagation.

11. The device according to claim 9, wherein at least a subset of said elements are adapted to modulate the acoustic beam in a QAM-16 constellation pattern.

12. The device according to claim 9, further comprising a structure for equalizing a phase delay of portions of said acoustic beam across the width of the acoustic beam after passing said elements and prior to interacting with a full beam width acousto-electric transducer.

13. The device according to claim 9, further comprising a splitter for splitting the acoustic beam, disposed past said elements along an acoustic beam propagation path, and a further set of elements for modulating said acoustic beam disposed to interact with a split portion of the acoustic beam.

14. The device according to claim 9, wherein said further set of elements includes structures or equalizing a relative phase delay across the beamwidth and imposing a further net phase delay to at least a portion of the acoustic wave.

17. The device according to claim 9, wherein at least a subset of said elements are adapted to modulate the acoustic beam in a QAM constellation pattern having about 2ⁿ evenly spaced signal states in said QAM constellation, wherein n is an integer greater than 1.

15. A device for modulating an acoustic wave, comprising an electroacoustic transducer for generating an acoustic wave on a substrate, said acoustic wave propagating along a propagation axis and having a beam width along an axis perpendicular to the propagation axis, a phase delay pad disposed along the propagation axis within the beam width, occupying less than the entire beam width;

and a summer for summing the acoustic power of the acoustic beam after interaction with the phase delay pad.

16. The device according to claim 15, further comprising a splitter, disposed before said summer, adapted for splitting the energy of the acoustic beam;

a phase delay equalizer for equalizing a phase delay of respective portions of the beam width;

an additional phase delay pad disposed along the propagation axis within the equalized beam width, occupying less than the entire equalized beam width; and

a further summer for summing the acoustic power of the equalized acoustic beam after interaction with the additional phase delay pad.

18. A method of modulating an acoustic beam having a beamwidth, comprising the steps of selectively providing, along a path of the acoustic beam, one or more elements which impose a phase delay on the acoustic wave, wherein at least a portion of elements are disposed over only a portion of the beamwidth, wherein at least a subset of said elements modulate the acoustic beam in a QAM constellation pattern, wherein said QAM constellation pattern has about 2ⁿ states, and wherein n is an integer greater than or equal to 2.

19. A method of modulating an acoustic beam having a beamwidth, comprising the steps of selectively providing, along a path of the acoustic beam, one or more elements which impose a phase delay on the acoustic wave, wherein at least a portion of elements are disposed over only a portion of the beamwidth, and equalizing a phase delay of portions of said acoustic beam across the width of the acoustic beam after passing said elements and prior to any transducing of the entire acoustic wave into an electrical signal.

20. A method of modulating an acoustic beam having a beamwidth, comprising the steps of selectively providing, along a path of the acoustic beam, one or more elements which impose a phase delay on the acoustic wave, wherein at least a portion of elements are disposed over only a portion of the beamwidth, and splitting the acoustic beam after passing said elements and subjecting a portion of said split beam to a further set of elements for modulating said acoustic beam.

21. A device for modulating an acoustic beam having a beamwidth, comprising:

one or more elements disposed along a predetermined path of an acoustic beam on a substrate, said elements being adapted for imposing a phase delay on the acoustic wave, wherein at least a portion of said elements are disposed over only a portion of the beamwidth, wherein at least a subset of said elements are adapted to modulate the acoustic beam in a QAM constellation pattern having about 2ⁿ evenly spaced signal states in said QAM constellation, wherein n is an integer greater than 1.

22. The device according to claim 21, wherein at least a subset of said elements are adapted to modulate the acoustic beam in a QAM-16 constellation pattern.

23. A device for modulating an acoustic beam having a beamwidth, comprising:

one or more elements disposed along a predetermined path of an acoustic beam on a substrate, said elements being adapted for imposing a phase delay on the acoustic wave, wherein at least a portion of said elements are disposed over only a portion of the beamwidth, and a structure for equalizing a phase delay of portions of said acoustic beam across the width of the acoustic beam after passing said elements and prior to interacting with a full beam width acousto-electric transducer.

24. A device for modulating an acoustic beam having a beamwidth, comprising:

one or more elements disposed along a predetermined path of an acoustic beam on a substrate, said elements being adapted for imposing a phase delay on the acoustic wave, wherein at least a portion of said elements are disposed over only a portion of the beamwidth, and a splitter for splitting the acoustic beam, disposed past said elements along an acoustic beam propagation path, and a further set of elements for modulating said acoustic beam disposed to interact with a split portion of the acoustic beam.