Wireless Chemical Sensor and Sensing Method for Use Therewith

• US 20090277789A1
• Filed: 05/11/2009
• Published: 11/12/2009
• Est. Priority Date: 05/09/2008
• Status: Abandoned Application

• Current Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Original Assignee: Space Administration, The Government Of The United States Of America, As Represented By The Secretary Of The Navy
• Inventors: Donald, M. Oglesby, Woodard, Stanley E., Shams, Qamar A., Taylor, Bryant Douglas
• Application Number:
  US12/463,481
• Publication Number:
  US 20090277789A1
• Time in Patent Office: Days
• US Class Current: 204/416
• CPC Class Codes: G01N 2291/0256 Adsorption, desorption, surface mass change, e.g. on biosensors
• CPC Class Codes: G01N 29/036 by measuring frequency or resonance of acoustic waves
• CPC Class Codes: H04Q 9/00 Arrangements in telecontrol or telemetry systems for selectively calling a substation from a main station, in which substation desired apparatus is selected for applying a control signal thereto or for obtaining measured values therefrom

Abstract

A wireless chemical sensor includes an electrical conductor and a dielectric material on the conductor. The conductor is electrically unconnected and is shaped for storage of an electric field and a magnetic field. In the presence of a time-varying magnetic field, the conductor resonates to generate harmonic electric and magnetic field responses, each of which has a frequency associated therewith. The dielectric material is selected such that it experiences changes in dielectric attributes thereof in the presence of a chemical-of-interest. Shifts from the sensor'"'"'s baseline frequency response indicate that the dielectric material has been exposed to the chemical-of-interest.

Claims

1. A wireless chemical sensor, comprising:

an electrical conductor having first and second ends and shaped between said first and second ends for storage of an electric field and a magnetic field, said first and second ends remaining electrically unconnected such that said electrical conductor so-shaped defines an unconnected open-circuit having inductance and capacitance wherein, in the presence of a time-varying magnetic field, said electrical conductor so-shaped resonates to generate harmonic electric and magnetic field responses, each of which has a frequency associated therewith; and

a dielectric material on said electrical conductor, said dielectric material experiencing changes in dielectric attributes thereof in the presence of a chemical-of-interest.

2. A wireless chemical sensor as in claim 1, further comprising a magnetic field response recorder for wirelessly transmitting said time-varying magnetic field to said electrical conductor and for wirelessly detecting said frequency associated with said magnetic field response so-generated and resulting from a current state of said dielectric attributes.

3. A wireless chemical sensor as in claim 1, further comprising an electric field response recorder for wirelessly transmitting said time-varying magnetic field to said electrical conductor and for wirelessly detecting said frequency associated with said electric field response so-generated and resulting from a current state of said dielectric attributes.

4. A wireless chemical sensor as in claim 1, wherein said electrical conductor comprises a thin-film trace.

5. A wireless chemical sensor as in claim 4, wherein said trace is uniform in width.

6. A wireless chemical sensor as in claim 4, wherein spacing between adjacent portions of said trace is uniform.

7. A wireless chemical sensor as in claim 4, wherein said trace is non-uniform in width.

8. A wireless chemical sensor as in claim 4, wherein spacing between adjacent portions of said trace is non-uniform.

9. A wireless chemical sensor as in claim 1, wherein said dielectric material is adapted to chemically react with the chemical-of-interest.

10. A wireless chemical sensor as in claim 1, wherein said dielectric material is adapted to absorb the chemical-of-interest.

11. A wireless chemical sensor as in claim 1, wherein said dielectric material encases said electrical conductor.

12. A wireless chemical sensor as in claim 1, wherein said electrical conductor and said dielectric material are flexible.

13. A wireless chemical sensor, comprising:

an electrically-insulating substrate;

an open-circuit pattern of electrically-conductive material on a face of said substrate, said pattern having two electrically unconnected ends, said pattern shaped for storage of an electric field and a magnetic field, said pattern having inductance and capacitance that allows said pattern to generate harmonic electric and magnetic field responses when in the presence of a time-varying magnetic field, each of said electric and magnetic field responses having a frequency associated therewith; and

a dielectric material on said electrical conductor, said dielectric material experiencing changes in dielectric attributes thereof in the presence of a chemical-of-interest.

14. A wireless chemical sensor as in claim 13, further comprising a magnetic field response recorder for wirelessly transmitting said time-varying magnetic field to said pattern and for wirelessly detecting said frequency associated with said magnetic field response so-generated and resulting from a current state of said dielectric attributes.

15. A wireless chemical sensor as in claim 13, further comprising an electric field response recorder for wirelessly transmitting said time-varying magnetic field to said pattern and for wirelessly detecting said frequency associated with said electric field response so-generated and resulting from a current state of said dielectric attributes.

16. A wireless chemical sensor as in claim 13, wherein said substrate is flexible.

17. A wireless chemical sensor as in claim 13, wherein said first face is planar and wherein said pattern is a spiral trace.

18. A wireless chemical sensor as in claim 17, wherein said spiral trace is uniform in width.

19. A wireless chemical sensor as in claim 17, wherein spacing between adjacent portions of said spiral trace is uniform.

20. A wireless chemical sensor as in claim 17, wherein said spiral trace is non-uniform in width.

21. A wireless chemical sensor as in claim 17, wherein spacing between adjacent portions of said spiral trace is non-uniform.

22. A wireless chemical sensor as in claim 13, wherein said dielectric material is adapted to chemically react with the chemical-of-interest.

23. A wireless chemical sensor as in claim 13, wherein said dielectric material is adapted to absorb the chemical-of-interest.

24. A wireless chemical sensor, comprising:

an electrical conductor in the form of a thin-film trace having first and second ends and shaped to form a pattern that can store an electric field and a magnetic field, said first and second ends remaining electrically unconnected such that said electrical conductor so-shaped defines an unconnected open-circuit having inductance and capacitance wherein, in the presence of a time-varying magnetic field, said electrical conductor so-shaped resonates to generate harmonic electric and magnetic field responses, each of which has a frequency associated therewith;

a dielectric material on said electrical conductor, said dielectric material experiencing changes in dielectric attributes thereof in the presence of a chemical-of-interest; and

a field response recorder for wirelessly transmitting said time-varying magnetic field to said electrical conductor and for wirelessly detecting said frequency associated with at least one of said electric and magnetic field responses so-generated and resulting from a current state of said dielectric attributes.

25. A wireless chemical sensor as in claim 24, wherein said trace is uniform in width.

26. A wireless chemical sensor as in claim 24, wherein spacing between adjacent portions of said trace is uniform.

27. A wireless chemical sensor as in claim 24, wherein said trace is non-uniform in width.

28. A wireless chemical sensor as in claim 24, wherein spacing between adjacent portions of said trace is non-uniform.

29. A wireless chemical sensor as in claim 24, wherein said dielectric material is adapted to chemically react with the chemical-of-interest.

30. A wireless chemical sensor as in claim 24, wherein said dielectric material is adapted to absorb the chemical-of-interest.

31. A wireless chemical sensor as in claim 24, wherein said dielectric material encases said electrical conductor.

32. A wireless chemical sensor as in claim 24, wherein said electrical conductor and said dielectric material are flexible.

33. A method of sensing the presence of a chemical-of-interest, comprising the steps of:

providing an electrical conductor having first and second ends and shaped between said first and second ends for storage of an electric field and a magnetic field, said first and second ends remaining electrically unconnected such that said electrical conductor so-shaped defines an unconnected open-circuit having inductance and capacitance wherein, in the presence of a time-varying magnetic field, said electrical conductor so-shaped resonates to generate harmonic electric and magnetic field responses, each of which has a frequency associated therewith;

overlaying at least a portion of said electrical conductor so-shaped with a dielectric material that experiences changes in dielectric attributes thereof in the presence of a chemical-of-interest;

recording a baseline frequency response for said at least one of said electric and magnetic field responses so-generated when the chemical-of-interest is not present; and

monitoring said at least one of said electric and magnetic field responses so-generated for changes in frequency with respect to said baseline frequency response as an indication of the presence of the chemical-of-interest.