Passive wireless acoustic wave chemical sensor

• US 20060049714A1
• Filed: 09/03/2004
• Published: 03/09/2006
• Est. Priority Date: 09/03/2004
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Liu, James, Repko, Mark A., Dierauer, Peter P.
• Granted Patent: US 7,205,701 B2
• Time in Patent Office: Days
• US Class Current: 310/313.R
• CPC Class Codes: G01N 2291/011 Velocity or travel time
• CPC Class Codes: G01N 2291/014 Resonance or resonant frequency
• CPC Class Codes: G01N 2291/0256 Adsorption, desorption, surface mass change, e.g. on biosensors
• CPC Class Codes: G01N 2291/0422 Shear waves, transverse waves, horizontally polarised waves
• CPC Class Codes: G01N 2291/0423 Surface waves, e.g. Rayleigh waves, Love waves
• CPC Class Codes: G01N 2291/101 one transducer
• CPC Class Codes: G01N 29/022 Fluid sensors based on microsensors, e.g. quartz crystal-microbalance [QCM], surface acoustic wave [SAW] devices, tuning forks, cantilevers, flexural plate wave [FPW] devices microdevices per se B81B
• CPC Class Codes: G01N 29/2462 Probes with waveguides, e.g. SAW devices
• CPC Class Codes: G01S 13/755 using delay lines, e.g. acoustic delay lines

Abstract

A passive wireless acoustic wave chemical sensor can be utilized for monitoring the concentration of an analyte in a substance such as blood. Such an acoustic wave chemical sensor can be configured to include one or more interdigital transducers and a selective coating formed upon a piezoelectric substrate. The coating and the interdigital transducer(s) can be used to convert electrical signal to surface waves thereof. An antenna can be connected to the acoustic wave device, wherein the antenna receives one or more input signals, which excite the acoustic device and to produce an output signal that is related to the concentration of the analyte of interest.

Claims

1. A chemical sensor system for sensing a chemical and/or biochemical constituent, the chemical sensor system comprising:

a surface acoustic wave device having an absorbing layer, wherein the absorbing layer absorbs the chemical and/or biochemical constituent and affects an output signal of the surface acoustic wave device;

means for wirelessly providing power to the surface acoustic wave device; and

means for wirelessly receiving the output signal from the surface acoustic wave device.

2. The chemical sensor system of claim 1 wherein the chemical and/or biochemical constituent is glucose.

3. The chemical sensor system of claim 1 wherein the means for wirelessly providing power to the surface acoustic wave device includes an interrogator.

4. The chemical sensor system of claim 3 wherein the means for wirelessly receiving the output signal from the surface acoustic wave device includes the interrogator.

5. The chemical sensor system of claim 1 wherein the absorbing layer absorbs the chemical and/or biochemical constituent and affects a time delay of the output signal relative to the input signal.

6. The chemical sensor system of claim 1 wherein the absorbing layer absorbs the chemical and/or biochemical constituent and affects a frequency of the output signal of the surface acoustic wave device.

7. The chemical sensor system of claim 1 further comprising an antenna coupled to the surface acoustic wave device for wirelessly receiving an input signal, the input signal providing power to the surface acoustic wave device.

8. The chemical sensor system of claim 1 further comprising an antenna coupled to the surface acoustic wave device for wirelessly transmitting the output signal.

9. The chemical sensor system of claim 1 wherein the surface acoustic wave device has at least one interdigital transducer on a piezoelectric substrate, wherein the at least one interdigital transducer produces an acoustic wave in the piezoelectric substrate along a path.

10. The chemical sensor system of claim 9 wherein the absorbing layer is coupled to the piezoelectric substrate along at least part of the path, the absorbing layer affecting the acoustic wave along the path.

11. The chemical sensor system of claim 10 wherein the surface acoustic wave device includes one or more reflectors situated on the piezoelectric substrate for reflecting the acoustic wave back toward the at least one interdigital transducer.

12. The chemical sensor system of claim 11 wherein the absorbing layer is situated between the at least one interdigital transducer and the one or more reflectors.

13. The chemical sensor system of claim 10 wherein the surface acoustic wave device includes one or more first reflectors situated on one side of the at least one interdigital transducer, and one or more second reflectors situated on opposite side of the at least one interdigital transducer.

14. The chemical sensor system of claim 13 wherein the absorbing layer is situated between the at least one interdigital transducer and the one or more first reflectors.

15. The chemical sensor system of claim 9 wherein the surface acoustic wave device has at least one interdigital transducer on a first side of the piezoelectric substrate, and wherein one or more other SAW sensors are positioned on the first side of the piezoelectric substrate.

16. The chemical sensor system of claim 15 wherein the one or more other SAW sensors includes a pressure sensor.

17. The chemical sensor system of claim 16 wherein the one or more other SAW sensors includes a temperature.

18. The chemical sensor system of claim 9 wherein the surface acoustic wave device has at least one interdigital transducer on a first side of the piezoelectric substrate, and wherein one or more other SAW sensors are positioned on a second opposite side of the piezoelectric substrate.

19. The chemical sensor system of claim 18 wherein the one or more other SAW sensors includes a pressure sensor.

20. The chemical sensor system of claim 18 wherein the one or more other SAW sensors includes a temperature.

21. A chemical sensor for sensing a chemical and/or biochemical constituent, the chemical sensor comprising:

a surface acoustic wave device having an absorbing layer, wherein the absorbing layer absorbs the chemical and/or biochemical constituent and affects an output signal of the surface acoustic wave device;

means for wirelessly receiving a power signal to power the surface acoustic wave device; and

means for wirelessly transmitting the output signal.

22. The chemical sensor of claim 21 wherein the surface acoustic wave device has at least one interdigital transducer on a piezoelectric substrate, wherein the at least one interdigital transducer produces an acoustic wave in the piezoelectric substrate along a path.

23. The chemical sensor of claim 22 wherein the absorbing layer is coupled to the piezoelectric substrate along at least part of the path, the absorbing layer affecting the acoustic wave along the path.

24. The chemical sensor of claim 23 wherein the surface acoustic wave device includes one or more reflectors situated on the piezoelectric substrate for reflecting the acoustic wave back toward the at least one interdigital transducer.

25. The chemical sensor of claim 24 wherein the absorbing layer is situated between the at least one interdigital transducer and the one or more reflectors.

26. The chemical sensor of claim 22 wherein the piezoelectric substrate includes quartz.

27. The chemical sensor of claim 22 wherein the piezoelectric substrate includes a polymeric piezoelectric material.

28. The chemical sensor of claim 22 wherein the piezoelectric substrate includes a bio-inert ceramic.

29. The chemical sensor of claim 28 wherein the bio-inert ceramic includes Alumina.

30. A method for sensing a chemical and/or biochemical constituent, the method comprising the steps of:

providing a surface acoustic wave device having an absorbing layer, wherein the absorbing layer absorbs the chemical and/or biochemical constituent and affects an output signal of the surface acoustic wave device;

exposing the absorbing layer to the chemical and/or biochemical constituent;

wirelessly providing power to the surface acoustic wave device via a power signal; and

wirelessly receiving the output signal from the surface acoustic wave device.

31. A method according to claim 30 further comprising the step of wirelessly providing a desorb signal to the surface acoustic wave device, wherein the desorb signal causes the surface acoustic wave device to produce an acoustic wave that vibrates and causes heat in the absorbing layer, thereby causing the absorbing layer to desorb at least some of the absorbed chemical and/or biochemical constituent.

32. A method according to claim 31 wherein the desorb signal is of a higher amplitude than the power signal.

33. A method according to claim 31 wherein the desorb signal has a different frequency than the power signal.

34. A method according to claim 31 wherein the surface acoustic wave device can be excited in multiple modes, and the desorb signal excites a different mode than the power signal.

35. A method for sensing a chemical and/or biochemical constituent, the method comprising the steps of:

providing a surface acoustic wave device having an absorbing layer, wherein the absorbing layer absorbs the chemical and/or biochemical constituent and affects an output signal of the surface acoustic wave device;

exposing the absorbing layer to the chemical and/or biochemical constituent;

providing an initialization signal to the surface acoustic wave device, the initialization signal causing the surface acoustic wave device to produce an acoustic wave that helps break down bonds between the absorbing layer and the chemical and/or biochemical constituent to increase the response time of the surface acoustic wave device;

providing power to the surface acoustic wave device via a power signal; and

receiving the output signal from the surface acoustic wave device, wherein the output signal is related to the concentration of the chemical and/or biochemical constituent.

36. A method according to claim 35 wherein the surface acoustic wave device can be excited in multiple modes, and the initialization signal excites a different mode than the power signal.

37. A method according to claim 36 wherein the initialization signal excites a shear-horizontal mode.

38. A method according to claim 35 wherein the initialization signal excites a higher amplitude acoustic wave in the surface acoustic wave device than the power signal.

39. A method according to claim 35 wherein the surface acoustic wave device can be excited in multiple modes, and the power signal excites two or more modes.

40. A method according to claim 35 wherein the initialization signal has a different frequency than the power signal.

41. A method according to claim 35 further comprising the step of providing a desorb signal after the receiving step, wherein the desorb signal is of a higher amplitude than the power signal.

42. A method according to claim 41 further comprising the step of providing a desorb signal after the receiving step, wherein the desorb signal has a different frequency than the power signal.

43. A method according to claim 41 further comprising the step of providing a desorb signal after the receiving step, wherein the surface acoustic wave device can be excited in multiple modes, and the desorb signal excites a different mode than the power signal.

44. A chemical sensing system for sensing a chemical and/or biochemical, comprising:

a surface acoustic wave sensor having at least one interdigital transducer above a piezoelectric substrate, the surface acoustic wave sensor producing an acoustic wave in the piezoelectric substrate along a path;

an absorbing substance coupled to the piezoelectric substrate along at least part of the path, the absorbing substance absorbing the chemical and/or biochemical;

an antenna connected to said at least one interdigital transducer, wherein said antenna receives at least one input signal, which excites at least one of the interdigital transducers to produce the acoustic wave in the piezoelectric substrate along the path.

45. The chemical sensing system of claim 44, wherein at least one of the interdigital transducers receives the acoustic wave in the piezoelectric substrate after passing along the path, and produces an output signal that is related to a concentration of the chemical and/or biochemical absorbed in the absorbing substance.

46. The chemical sensing system of claim 45 wherein the output signal is wirelessly transmitted.

47. The chemical sensing system of claim 45 wherein the at least one input signal is wirelessly transmitted and received by the antenna.

48. The chemical sensing system of claim 45 wherein the at least one input signal has a frequency that is greater than 2.5 GHz.

49. The chemical sensing system of claim 45 wherein the at least one input signal has a frequency that is greater than 4.0 GHz.

50. The chemical sensing system of claim 48 wherein the output signal has a frequency that is greater than 2.5 GHz.

51. The chemical sensing system of claim 50 wherein the output signal has a frequency that is greater than 4.0 GHz.

52. A method for sensing a chemical and/or biochemical constituent in a fluid, the method comprising the steps of:

providing a surface acoustic wave sensor for monitoring a concentration of the chemical and/or biochemical constituent in the fluid, wherein the surface acoustic wave sensor includes at least one interdigital transducer and a chemical/biological absorbing coating formed above a piezoelectric substrate, wherein said at least one interdigital transducer is selected to convert electrical signal to surface waves in the piezoelectric substrate; and

connecting an antenna to the surface acoustic wave sensor, wherein said antenna receives at least one input signal, which excites said at least one interdigital transducer to produce an output signal that is related to the concentration of the chemical and/or biochemical constituent in the fluid; and

providing a transmitter, wherein the transmitter produces the input signal that is received by the antenna, wherein the transmitter has a multiple mode interrogation;

a first interrogation mode employing a higher-amplitude signal that induces a shear-horizontal mode in the piezoelectric substrate, wherein the first interrogation mode helps breaks down bonds between the chemical/biological absorbing coating and the chemical and/or biochemical constituent in the fluid; and

a second interrogation mode employing a lower-amplitude signal, wherein the second mode is used to obtain a measure of the concentration of the chemical and/or biochemical constituent in the fluid.

53. The method of claim 52, wherein the chemical and/or biochemical constituent is glucose.

54. The method of claim 52, wherein the fluid is blood.

55. The method of claim 54 wherein the surface acoustic wave sensor and the antenna are implantable within a human body for monitoring said blood.

56. The method of claim 55, wherein the transmitter is located outside of the human body.

57. A chemical sensor system for sensing a chemical and/or biochemical constituent, the chemical sensor system comprising:

a surface acoustic wave device having an absorbing layer, wherein the absorbing layer absorbs the chemical and/or biochemical constituent and affects an output signal of the surface acoustic wave device, the surface acoustic wave device adapted to operated at a frequency that is above 2.5 GHz.

58. The chemical sensor system of claim 57 wherein the surface acoustic wave device adapted to operated at a frequency that is above 4.0 GHz.