Surface acoustic wave transponder configuration

• US 6,388,360 B1
• Filed: 05/25/2000
• Issued: 05/14/2002
• Est. Priority Date: 08/18/1997
• Status: Expired due to Fees

• Current Assignee: X-Cyte Inc.
• Original Assignee: X-Cyte Inc.
• Inventors: Nysen, Paul A., Skeie, Halvor
• Primary Examiner(s): Dougherty, Thomas M.
• Application Number:
  US09/583,989
• Time in Patent Office: 719 Days
• Field of Search: 310/313.D, 310/313.R, 333/156, 333/157, 342/51
• 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. An acoustic wave identification transponder device, comprising a substrate having a surface, an electroacoustic transducer generating an acoustic wave in said substrate, a set of encoding members associated with said surface disposed to interact with energy of the acoustic wave for modifying a waveform thereof, and at least one element disposed along the path of the acoustic wave which interacts with, and reemits as a corresponding acoustic wave, at least a portion of the acoustic wave along an exit acoustic path which is not parallel to an incident acoustic path with respect to said surface.

2. The device according to claim 1, further comprising at least one additional element disposed along a path of the acoustic wave which interacts with, and reemits, at least a portion of the acoustic wave along an exit acoustic path which is not parallel to an incident acoustic path.

3. The device according to claim 1, wherein said element redirects at least a portion of the acoustic wave at right angles.

4. The device according to claim 1, wherein said element allows at least a portion of the acoustic wave to pass coaxially with said incident acoustic path.

5. The device according to claim 1, wherein said element redirects the axis of propagation of the acoustic wave with high efficiency.

6. The device according to claim 2, wherein said additional element acts in sequence with said element to redirect a portion of the acoustic wave.

7. The device according to claim 6, wherein an exit path of said element is parallel to an exit path of said additional element.

8. The device according to claim 6, wherein an exit path of said element is antiparallel to an exit path of said additional element.

9. The device according to claim 1, wherein the acoustic energy is reflected back along its incident path.

10. The device according to claim 1, wherein the acoustic energy follows a path on said substrate substantially without backtracking along an incident path.

11. The device according to claim 1, wherein said substrate is piezoelectric and said element comprises a conductor deposited on a surface of said piezoelectric substrate.

12. The device according to claim 1, wherein said element comprises a right angle trackchanger.

13. The device according to claim 1, wherein said substrate comprises a piezoelectric composition, and said element comprises an arrangement of conductive strips arranged to transduce an incident acoustic wave traveling in said piezoelectric substrate into electric signals in said conductive strips, and a further arrangement of conductive strips arranged to transduce the electric signals into an emitted acoustic wave propagating in said piezoelectric substrate, a path of the incident acoustic wave differing from a path of the emitted acoustic wave.

14. The device according to claim 2, wherein said element and said additional element are together configured as a reflective array compressor.

15. The device according to claim 1, wherein said element is part of an array of semireflective elements disposed along an acoustic path of the acoustic wave, elements of said array selectively reflecting portions of the acoustic wave along axes having a propagation component orthogonal to an incident acoustic wave and allowing other portions to pass unreflected.

16. 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, wherein the improvement comprises said encoding elements together comprising means for selectively modifying a phase and amplitude of an incident acoustic wave to quadrature amplitude encode information on the acoustic wave.

17. The device method according to claim 16, wherein said set of encoding elements element comprises a set of members disposed bilaterally symmetrical with respect to an axis of acoustic beam propagation.

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

20. The device method according to claim 16, further means 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 any transducing of the entire acoustic wave into an electrical signal.

21. The device method according to claim 16, further comprising means for splitting the acoustic beam after passing said set of elements, wherein a portion of said split beam is subjected to a operation of a further set of elements for modulating said acoustic beam.

22. The device method according to claim 21, wherein said further set of elements includes structures for equalizing a relative phase delay across the beamwidth and imposing a further net phase delay to at least a portion of the acoustic wave.

23. The device according to claim 16, further comprising means for splitting the energy of the acoustic beam;

means 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 summer for summing the acoustic power of the equalized acoustic beam after interaction with the additional phase delay pad, wherein summer outputs a split portion of the acoustic beam and the summed acoustic power of the equalized acoustic beam.

24. The device according to claim 16, wherein said acoustic wave is a beam propagating along an axis and having a beam width, said set of encoding elements comprising 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.

25. The device according to claim 24, further comprising, before said summer, a splitter for splitting the energy of the acoustic beam;

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

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

said summer summing the acoustic power of the equalized acoustic beam after interaction with the additional phase delay pad, and operating to sum the acoustic power of the equalized acoustic beam after interaction with the additional phase delay pad.

26. The device according to claim 16, further comprising a trackchanger disposed along a path of the acoustic wave, for altering a propagation direction of the acoustic wave.

27. An acoustic wave identification transponder device, having a piezoelectric substrate, an electroacoustic transducer generating an acoustic wave in said piezoelectric substrate, and a set of conductive encoding elements disposed in a path of the acoustic wave on the piezoelectric substrate, for selectively quadrature amplitude modulation encoding of information on the acoustic wave with a code-space having at least 4 quadrature amplitude modulation states.