Wireless Sensing System Using Open-Circuit, Electrically-Conductive Spiral-Trace Sensor

• US 20070181683A1
• Filed: 02/05/2007
• Published: 08/09/2007
• Est. Priority Date: 02/06/2006
• Status: Active Grant

• Current Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Original Assignee: Administrator of The National Aeronautics and Space Administration
• Inventors: Taylor, Bryant D., Woodard, Stanley E.
• Granted Patent: US 8,430,327 B2
• Time in Patent Office: Days
• US Class Current: 235/451
• 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 sensing system includes a sensor made from an electrical conductor shaped to form an open-circuit, electrically-conductive spiral trace having inductance and capacitance. In the presence of a time-varying magnetic field, the sensor resonates to generate a harmonic response having a frequency, amplitude and bandwidth. A magnetic field response recorder wirelessly transmits the time-varying magnetic field to the sensor and wirelessly detects the sensor'"'"'s response frequency, amplitude and bandwidth.

Claims

1. A wireless sensing system, comprising:

an electrical conductor having first and second ends and shaped to form a spiral between said first and second ends, said conductor so-shaped defining an open-circuit having inductance and capacitance wherein, in the presence of a time-varying magnetic field, said conductor so-shaped resonates to generate a harmonic magnetic field response having a frequency, amplitude and bandwidth; and

a magnetic field response recorder for wirelessly transmitting said time-varying magnetic field to said conductor so-shaped and for wirelessly detecting said frequency, amplitude and bandwidth.

2. A wireless sensing system as in claim 1 wherein said conductor comprises a thin-film trace.

3. A wireless sensing system as in claim 2 wherein said trace is uniform in width.

4. A wireless sensing system as in claim 2 wherein spacing between adjacent portions of said trace is uniform.

5. A wireless sensing system as in claim 2 wherein said trace is non-uniform in width.

6. A wireless sensing system as in claim 2 wherein spacing between adjacent portions of said trace is non-uniform.

7. A wireless sensing system as in claim 1 wherein said conductor is configured to affect said capacitance and inductance in a way that makes said amplitude at least 10 db more than an amplitude of ambient noise at said magnetic field response recorder.

8. A wireless sensing system as in claim 1 further comprising a dielectric material disposed between adjacent portions of said conductor.

9. A wireless sensing system as in claim 1 further comprising a dielectric material disposed on said conductor.

10. A wireless sensing system as in claim 1 further comprising a dielectric material disposed between adjacent portions of said conductor and on said conductor.

11. A wireless sensing system, comprising:

a non-conductive substrate;

an open-circuit electrically-conductive spiral trace deposited on said substrate, said spiral trace having inductance and capacitance that (i) allows said spiral trace to generate a harmonic magnetic field response having a frequency, amplitude and bandwidth in the presence of a time-varying magnetic field, and (ii) causes said amplitude to be at least 10 dB more than ambient noise; and

a magnetic field response recorder for wirelessly transmitting said time-varying magnetic field to said spiral trace and for wirelessly detecting said frequency, amplitude and bandwidth.

12. A sensing system as in claim 11 wherein said substrate is flexible.

13. A wireless sensing system as in claim 11 wherein said spiral trace is uniform in width.

14. A wireless sensing system as in claim 11 wherein spacing between adjacent portions of said spiral trace is uniform.

15. A wireless sensing system as in claim 11 wherein said spiral trace is non-uniform in width.

16. A wireless sensing system as in claim 11 wherein spacing between adjacent portions of said spiral trace is non-uniform.

17. A wireless sensing system as in claim 11 further comprising a dielectric material disposed between adjacent portions of said spiral trace.

18. A wireless sensing system as in claim 11 further comprising a dielectric material disposed on said spiral trace.

19. A wireless sensing system as in claim 11 further comprising a dielectric material disposed between adjacent portions of said spiral trace and on said spiral trace.

20. A wireless sensing system, comprising:

a non-conductive, flexible substrate;

an open-circuit electrically-conductive spiral trace deposited on said substrate, said spiral trace having inductance and capacitance that (i) allows said spiral trace to generate a harmonic magnetic field response having a frequency, amplitude and bandwidth in the presence of a time-varying magnetic field, and (ii) causes said amplitude to be at least 10dB more than ambient noise;

a dielectric material disposed between adjacent portions of said spiral trace and on said spiral trace wherein said spiral trace is encased by said substrate and said dielectric material; and

a magnetic field response recorder for wirelessly transmitting said time-varying magnetic field to said spiral trace and for wirelessly detecting said frequency, amplitude and bandwidth.

21. A wireless sensing system as in claim 20 wherein said spiral trace is uniform in width.

22. A wireless sensing system as in claim 20 wherein spacing between adjacent portions of said spiral trace is uniform.

23. A wireless sensing system as in claim 20 wherein said spiral trace is non-uniform in width.

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

25. A wireless sensing system, comprising:

an arrangement of inductively, wherein said arrangement is fixed;

each said sensor being an electrical conductor having first and second ends, said conductor shaped to form a spiral between said first and second ends and further shaped to define an open-circuit having inductance and capacitance;

at least one said sensor directly powered and interrogated by a magnetic field response recorder wherein, in the presence of a time-varying magnetic field, said sensor resonates to generate one or more harmonic responses each having a frequency, amplitude, and bandwidth resulting from resonant responses of said inductively coupled arrangement of sensors;

said responses of said arrangement of sensors correlated to the magnitude of one or more physical quantities; and

a magnetic field response recorder for (i) wirelessly transmitting said time-varying magnetic field to said sensor directly powered and interrogated and (ii) for wirelessly detecting said frequencies, amplitudes and bandwidths of all said arranged sensors.

26. A wireless sensing system as in claim 25 wherein each said conductor comprises a thin-film trace.

27. A wireless sensing system as in claim 26 wherein said traces are uniform in width.

28. A wireless sensing system as in claim 26 wherein spacing between adjacent portions of said traces is uniform.

29. A wireless sensing system as in claim 26 wherein said traces are non-uniform in width.

30. A wireless sensing system as in claim 26 wherein spacing between adjacent portions of said traces is non-uniform.

31. A wireless sensing system as in claim 25 wherein said conductors are configures to affect said capacitance and inductance in a way that makes said amplitudes at least 10 dB more than an amplitude of ambient noise at said magnetic field response recorder.

32. A wireless sensing system as in claim 25 further comprising a dielectric material disposed between adjacent portions of at least one of said conductors.

33. A wireless sensing system as in claim 25 further comprising a dielectric material disposed on at least one of said conductors.

34. A wireless sensing system as in claim 25 further comprising a dielectric material disposed between adjacent portions of at least one of said conductors and on at least one of said conductors.

35. A wireless sensing system as in claim 25 wherein said arrangement of sensors is deposited on a non-conductive substrate.