Multiple-mode acoustic wave sensor

• US 20060230834A1
• Filed: 04/14/2005
• Published: 10/19/2006
• Est. Priority Date: 04/14/2005
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Rhodes, Michael L., Rahman, Aziz, Liu, James ZT
• Granted Patent: US 7,267,009 B2
• Time in Patent Office: Days
• US Class Current: 73/649
• CPC Class Codes: G01L 1/165 with acoustic surface waves
• CPC Class Codes: G01L 9/0025 with acoustic surface waves
• 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 2291/0426 Bulk waves, e.g. quartz crystal microbalance, torsional waves
• CPC Class Codes: G01N 2291/0427 Flexural waves, plate waves, e.g. Lamb waves, tuning fork, cantilever
• 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

Abstract

A multiple-mode acoustic wave sensor apparatus includes an acoustic wave device comprising a piezoelectric substrate and at least one electrode on the substrate. When such sensor is used in a wireless configuration, a plurality of antennas can be configured on the substrate in association with the acoustic wave device, wherein each antenna among the plurality of antennas is responsive to varying interrogation signals transmitted wirelessly to the plurality of antennas in order to excite multiple frequency modes via at least one interdigital transducer on the substrate and thereby passively detect multiple and varying parameters of a sensed material utilizing the acoustic wave device.

Claims

1. A multiple-mode acoustic wave sensor apparatus, comprising:

a wireless interrogation unit comprising a transmitter and a receiver;

an acoustic wave device comprising a piezoelectric substrate and at least one electrode on said piezoelectric substrate; and

a plurality of antennas configured on said piezoelectric substrate in association with said acoustic wave device, wherein each antenna among said plurality of antennas is responsive to varying interrogation signals transmitted wirelessly to said plurality of antennas from said wireless interrogation unit in order to excite multiple frequency modes via at least one interdigital transducer on said piezoelectric substrate and thereby passively detect multiple and varying parameters of a sensed material utilizing said acoustic wave device.

2. The apparatus of claim 1 wherein said varying interrogation signals transmitted wirelessly to said plurality of antennas comprise at least one input signal.

3. The apparatus of claim 1 wherein said varying interrogation signals transmitted wirelessly to said plurality of antennas comprise at least one power signal.

4. The apparatus of claim 1 wherein said varying interrogation signals transmitted wirelessly to said plurality of antennas in order to excite said multiple frequency modes comprising at least one of the following types of frequency modes:

a surface acoustic wave (SAW) mode, shear-horizontal surface acoustic wave (SH-SAW) mode, a pseudo surface acoustic wave (PSAW) mode, and a leak surface acoustic wave (LSAW) mode.

5. The apparatus of claim 4 wherein said multiple frequency modes further comprise at least one of the following types of frequency modes:

flexural plate wave (FPW), acoustic plate shear-horizontal acoustic plate mode (SH-APM), amplitude plate mode (APM), thickness shear mode (TSM), bulk acoustic wave (BAW) mode, transverse mode, surface skimming mode, surface transverse mode, harmonic mode and overtone mode.

6. The apparatus of claim 1 wherein said acoustic wave device is configured to suppress at least some predetermined frequency modes among said multiple frequency modes while permitting the excitation of other frequency modes thereof via said acoustic wave device.

7. The apparatus of claim 1 wherein an excitation of said multiple frequency modes through said acoustic wave device permits a separation of temperature changes effects from pressure change effects thereof.

8. The apparatus of claim 1 wherein said piezoelectric substrate is configured from at least one of the following types of piezoelectric materials:

quartz, lithium niobate (LiNbO₃), lithium tantalite (LiTaO₃), Li₂B₄O₇, AlPO₄, GaPO₄, langasite (La₃Ga₅Si)₁₄), ZnO, and epitaxially grown nitrides including Al, Ga, or In.

9. The apparatus of claim 1 wherein said electrode comprises a material formed from at least one of the following types of material groups:

metals, alloys, or metal-nonmetal compounds.

10. The apparatus of claim 1 further comprising a reader unit for wirelessly transmitting said varying interrogation signals to said plurality of antennas in order to excite said multiple frequency modes.

11. A multiple-mode acoustic wave sensor apparatus, comprising:

an acoustic wave device comprising a piezoelectric substrate and at least one electrode on said piezoelectric substrate; and

a plurality of oscillators associated with said acoustic wave sensor, wherein each oscillator among said plurality of oscillators is responsive at least one signal in order to excite multiple frequency modes via said acoustic wave device, such that each of said oscillators transmits an excitation signal through a wired connections to said acoustic wave device and wherein said acoustic wave device is configured to suppress at least some predetermined frequency modes among said multiple frequency modes while permitting the excitation of other frequency modes thereof via said acoustic wave sensor device.

12. The apparatus of claim 11 wherein each of said oscillators transmits at least one signal through a wired connection to said acoustic wave device in order to excite said multiple frequency modes comprising at least one of the following types of frequency modes:

a surface acoustic wave (SAW) mode, shear-horizontal surface acoustic wave (SH-SAW) mode, a pseudo surface acoustic wave (PSAW) mode, and a leak surface acoustic wave (LSAW) mode.

13. The apparatus of claim 12 wherein said multiple frequency modes further comprise at least one of the following types of frequency modes:

flexural plate mode (FPM), acoustic plate shear-horizontal acoustic plate mode (SH-APM), amplitude plate mode (APM), thickness shear mode (TSM), bulk acoustic wave (BAW) mode, transverse mode, surface skimming mode, surface transverse mode, harmonic mode and overtone mode.

14. The method of claim 11 further comprising the step of exciting said multiple frequency modes through said acoustic wave device to permit a separation of temperature change effects from physical and chemical measurand change effects thereof including pressure, torque, viscosity, density, corrosivity, conductivity, pH, flow, a lubricity, a turbidity, a humidity, a particulate concentration, a total base number, and a total acid number.

15. A multiple-mode acoustic wave sensor method, comprising the steps of:

providing a wireless interrogation unit comprising a transmitter and a receiver;

forming an acoustic wave device comprising a piezoelectric substrate and at least one interdigital transducer formed as an electrode on said piezoelectric substrate; and

configuring a plurality of antennas on said piezoelectric substrate in association with said acoustic wave device, wherein each antenna among said plurality of antennas is responsive to varying interrogation signals transmitted wirelessly to said plurality of antennas from said wireless interrogation unit in order to excite multiple frequency modes via at least one interdigital transducer on said piezoelectric substrate and thereby passively detect multiple and varying parameters of a sensed material utilizing said acoustic wave device.

16. The method of claim 15 further comprising the step of exciting said multiple frequency modes through said acoustic wave device on order separate temperature changes effects from pressure change effects thereof.

17. The method of claim 15 further comprising the step of exciting said multiple frequency modes through said acoustic wave device to separate temperature change effects from torque change effects thereof.

18. The method of claim 15 further comprising the step of exciting said multiple frequency modes through said acoustic wave device to separate temperature change effects from viscosity change effects thereof.

19. The method of claim 15 further comprising the step of exciting said multiple frequency modes through said acoustic wave device to separate temperature change effects from density change effects thereof.

20. The method of claim 15 further comprising the step of exciting said multiple frequency modes through said acoustic wave device to separate temperature changes effects from corrosivity change effects thereof.

21. The method of claim 15 further comprising the step of exciting said multiple frequency modes through said acoustic wave device to permit a separation of temperature change effects from physical and chemical measurand change effects thereof including conductivity, pH, flow, a lubricity, a turbidity, a humidity, a particulate concentration, a total base number, and a total acid number.