Wireless Chemical Sensor and Sensing Method for Use Therewith

• US 20100233821A1
• Filed: 05/11/2009
• Published: 09/16/2010
• Est. Priority Date: 05/09/2008
• Status: Active Grant

• Current Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Original Assignee: U.S.A. as represented by the Administrator of the National Aeronautics and Space Administration
• Inventors: Oglesby, Donald M., Woodard, Stanley E., Taylor, Bryant Douglas
• Granted Patent: US 8,673,649 B2
• Time in Patent Office: Days
• US Class Current: 436/149
• CPC Class Codes: G01N 27/021 before and after chemical transformation of the material
• CPC Class Codes: G01N 27/122 Circuits particularly adapted therefor, e.g. linearising circuits
• CPC Class Codes: G01N 27/26 by investigating electrochemical variables; by using electrolysis or electrophoresis
• CPC Class Codes: G01N 27/72 by investigating magnetic variables

Abstract

A wireless chemical sensor includes an electrical conductor and a material separated therefrom by an electric insulator. The electrical conductor is an unconnected open-circuit shaped for storage of an electric field and a magnetic field. In the presence of a time-varying magnetic field, the first electrical conductor resonates to generate harmonic electric and magnetic field responses. The material is positioned at a location lying within at least one of the electric and magnetic field responses so-generated. The material changes in electrical conductivity in the presence of a 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, amplitude and bandwidth associated therewith;

a material spaced apart from said electrical conductor at a location lying within at least one of said electric and magnetic field responses so-generated, said material changing in electrical conductivity in the presence of a chemical-of-interest; and

an electric insulator disposed between said first electrical conductor and said material.

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, amplitude and bandwidth associated with said magnetic field response so-generated.

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, amplitude and bandwidth associated with said electric field response so-generated.

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 material is adapted to chemically react with the chemical-of-interest.

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

11. A wireless chemical sensor as in claim 1, wherein said material comprises a sheet thereof.

12. A wireless chemical sensor as in claim 1, wherein said electric insulator comprises air.

13. A wireless chemical sensor as in claim 1, wherein said electric insulator encases said electrical conductor.

14. A wireless chemical sensor as in claim 1, wherein said electrical conductor and said material are coupled to said electric insulator.

15. A wireless chemical sensor as in claim 1, wherein said electrical conductor, said material, and said electric insulator are flexible.

16. A wireless chemical sensor, comprising:

an electrically-insulating substrate having opposing faces;

an open-circuit pattern of electrically-conductive material on a first face of said opposing faces 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, amplitude and bandwidth associated therewith; and

a material on a second face of said opposing faces of said substrate wherein said material lies within at least one of said electric and magnetic field responses so-generated, said material changing in electrical conductivity in the presence of a chemical-of-interest.

17. A wireless chemical sensor as in claim 16, further comprising a magnetic field response recorder for wirelessly transmitting said time-varying magnetic field to said pattern and for wirelessly detecting said frequency, amplitude and bandwidth associated with said magnetic field response so-generated.

18. A wireless chemical sensor as in claim 16, further comprising an electric field response recorder for wirelessly transmitting said time-varying magnetic field to said pattern and for wirelessly detecting said frequency, amplitude and bandwidth associated with said electric field response so-generated.

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

20. A wireless chemical sensor as in claim 16, wherein said first face is planar and wherein said pattern is a spiral trace.

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

22. A wireless chemical sensor as in claim 20, wherein spacing between adjacent portions of said spiral trace is uniform.

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

24. A wireless chemical sensor as in claim 20, wherein spacing between adjacent portions of said spiral trace is non-uniform.

25. A wireless chemical sensor as in claim 16, wherein said material is adapted to chemically react with the chemical-of-interest.

26. A wireless chemical sensor as in claim 16, wherein said material is adapted to absorb the chemical-of-interest.

27. A wireless chemical sensor as in claim 16, wherein said substrate encases said pattern.

28. 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, amplitude and bandwidth associated therewith;

a material spaced apart from said electrical conductor at a location lying within at least one of said electric and magnetic field responses so-generated, said material changing in electrical conductivity in the presence of a chemical-of-interest;

an electric insulator disposed between said electrical conductor and said material; and

a field response recorder for wirelessly transmitting said time-varying magnetic field to said electrical conductor and for wirelessly detecting said frequency, amplitude and bandwidth associated with at least one of said electric and magnetic field responses so-generated.

29. A wireless chemical sensor as in claim 28, wherein said trace is uniform in width.

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

31. A wireless chemical sensor as in claim 28, wherein said trace is non-uniform in width.

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

33. A wireless chemical sensor as in claim 28, wherein said material is adapted to chemically react with the chemical-of-interest.

34. A wireless chemical sensor as in claim 28, wherein said material is adapted to absorb the chemical-of-interest.

35. A wireless chemical sensor as in claim 28, wherein said material comprises a sheet thereof.

36. A wireless chemical sensor as in claim 28, wherein said electric insulator comprises air.

37. A wireless chemical sensor as in claim 28, wherein said electric insulator encases said electrical conductor.

38. A wireless chemical sensor as in claim 28, wherein said electrical conductor and said material are coupled to said electric insulator.

39. A wireless chemical sensor as in claim 28, wherein said electrical conductor, said material, and said electric insulator are flexible.

40. 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, amplitude and bandwidth associated therewith;

positioning a material in a spaced-apart relationship with respect to said electrical conductor at a location lying within at least one of said electric and magnetic field responses so-generated, said material changing in electrical conductivity in the presence of a chemical-of-interest;

disposing an electric insulator between said electrical conductor and said material;

recording a baseline 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 with respect to said baseline response as an indication of the presence of the chemical-of-interest.

41. A method according to claim 40, wherein said step of disposing comprises the step of encasing said electrical conductor in said electric insulator.