ACOUSTIC WAVE DEVICE PHYSICAL PARAMETER SENSOR

• US 20090206844A1
• Filed: 02/14/2008
• Published: 08/20/2009
• Est. Priority Date: 02/14/2008
• Status: Active Grant

• Current Assignee: Microsemi Corporation (Microchip Technology Incorporated)
• Original Assignee: Delaware Capital Formation Incorporated (Dover Corporation)
• Inventors: Andle, Jeffrey C., Stevens, Daniel S., Sabah, Sabah
• Granted Patent: US 7,855,564 B2
• Time in Patent Office: Days
• US Class Current: 324/636
• CPC Class Codes: A61P 19/02 for joint disorders, e.g. arthritis, arthrosis
• CPC Class Codes: A61P 35/00 Antineoplastic agents
• CPC Class Codes: A61P 37/06 Immunosuppressants, e.g. drugs for graft rejection
• CPC Class Codes: G01N 29/02 Analysing fluids using acoustic emission techniques G01N29/14 ; constructional or flow details for analysing fluids G01N29/222; optoacoustic fluid cells G01N29/2425
• CPC Class Codes: G01R 33/095 extraordinary magnetoresistance sensors

Abstract

An acoustic wave sensor employs an electromagnetic device (EMD) to transduce and amplify the response of an impedance element to a physical measurand. One embodiment uses a magnetic field sensor employing a microelectromechanical system (MEMS) capacitor to affect a change in the response of a SAW filter.

Claims

1. A system for measuring a physical measurand comprising:

at least one variable impedance element probe responsive to at least one measurand; and

at least one electromagnetic device (EMD) having at least one port, wherein said at least one variable impedance element probe is operably connected to said at least one port, said at least one EMD being electrically responsive to said response of said variable impedance element probe.

2. The system of claim 1, further comprising:

a wireless interrogation device configured to measure said at least one electromagnetic device (EMD).

3. The system of claim 1, wherein said at least one electromagnetic device (EMD) is selected from the group consisting of:

cavity resonators, optical fiber delay lines, microwave cavity resonators, dielectric resonators, acoustic wave delay lines, acoustic wave resonator devices, magnetostatic wave (MSW) delay lines, MSW resonators, charge-coupled device (CCD) delay lines, acoustic charge transport (ACT) devices, stripline resonators, surface plasmon resonators, integrated optics resonators, and tunable laser optical resonators.

4. The system of claim 1, wherein said at least one electromagnetic device (EMD) is at least one acoustic wave device (AWD).

5. The system of claim 4, wherein said at least one acoustic wave device (AWD) is a stored energy resonator.

6. The system of claim 4, wherein said at least one acoustic wave device (AWD) is configured to reradiate electrical energy incident on an input port.

7. The system of claim 4, wherein each of said at least one acoustic wave devices (AWDs) comprises an input port and at least one sensing port, wherein said at least one variable impedance element probe is operably connected to said at least one sensing port.

8. The system of claim 7, wherein said at least one acoustic wave device (AWD) is a reflective-tap delay line comprising reflective taps, wherein at least one of said reflective taps comprises at least one interdigital transducer (IDT), said IDT comprising said at least one sensing port.

9. The system of claim 8, further comprising a plurality of said reflective taps providing an identification sequence specific to said system.

10. The sensor system of claim 4, wherein each of said at least one acoustic wave devices (AWDs) comprises an input port and at least one sensing port, wherein said at least one variable impedance element probe is operably connected to said at least one sensing port;

wherein said at least one variable impedance element probe is a variable capacitor responsive to magnetic fields.

11. The sensor system of claim 4, wherein each of said at least one acoustic wave devices (AWDs) comprises an input port and at least one sensing port, wherein said at least one variable impedance element probe is operably connected to said at least one sensing port;

wherein said at least one variable impedance element probe is a variable capacitor responsive to pressure.

12. The system of claim 1, wherein said physical measurand is selected from the group consisting of:

magnetic field, electric field, pressure, strain, stress, temperature, acoustic vibration, acceleration, chemical concentration, biochemical concentration, viscosity, density, and elastic modulus.

13. The system of claim 1, wherein said variable impedance element probe is a variable capacitor, wherein said variable capacitor capacitance value changes in response to motion of one or more elements of said variable capacitor.

14. The system of claim 13, wherein said variable capacitor is selected from the group consisting of:

a comb capacitor, a cantilever capacitor, and a suspended membrane capacitor.

15. The system of claim 1, wherein said variable impedance element probe is selected from the group consisting of:

a chemically responsive resistance, a chemical field-effect transistor (Chem-FET), and a metal-oxide-semiconductor field-effect transistor (MOSFET).

16. The system of claim 1, wherein said variable impedance element probe is an acoustic wave device (AWD) resonator.

17. The system of claim 1, wherein a component material of said variable impedance element probe is selected from the group consisting of:

Fe, Ni, Co, magnetite, and ferromagnetic alloy.

18. A method for measuring a physical measurand comprising the steps of:

changing an impedance of a variable impedance element probe, resulting from a physical measurand;

changing attributes of an acoustic wave device (AWD) from said impedance change;

interrogating said AWD;

receiving a response signal from said AWD; and

determining value of said physical measurand from said received signal.

19. The method of claim 18 wherein said interrogating step comprises a circuit selected from the group consisting of:

an oscillator circuit, a transmission circuit, a reflection circuit, and a passive wireless interrogation circuit.

20. A sensor device comprising:

An electromagnetic device (EMD) comprising at least one electrical port;

at least one variable impedance element probe operably coupled to said at least one electrical port, wherein said at least one impedance element probe is configured to be responsive to at least one physical measurand, and wherein said EMD is electrically responsive to a value of said at least one impedance element probe, a value of said EMD response being representative of said physical parameter.