Wireless tamper detection sensor and sensing system

• US 20090302111A1
• Filed: 09/28/2007
• Published: 12/10/2009
• Est. Priority Date: 09/28/2007
• Status: Active Grant

• Current Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Original Assignee: The United States of America As Represented By The Secretary of Agriculture
• Inventors: Taylor, Bryant D., Woodard, Stanley E.
• Granted Patent: US 8,042,739 B2
• Time in Patent Office: Days
• US Class Current: 235/449
• CPC Class Codes: G08B 13/2408 using ferromagnetic tags
• CPC Class Codes: G08B 13/2445 Tag integrated into item to be protected, e.g. source tagging
• CPC Class Codes: G08B 13/2471 Antenna signal processing by receiver or emitter
• CPC Class Codes: G08B 13/2474 Antenna or antenna activator geometry, arrangement or layout loop antennae H01Q1/22

Abstract

A wireless tamper detection sensor is defined by a perforated electrical conductor. The conductor is shaped to form a geometric pattern between first and second ends thereof such that the conductor defines an open-circuit that can store and transfer electrical and magnetic energy. The conductor resonates in the presence of a time-varying magnetic field to generate a harmonic response. The harmonic response changes when the conductor experiences a change in its geometric pattern due to severing of the conductor along at least a portion of the perforations. A magnetic field response recorder is used to wirelessly transmit the time-varying magnetic field and wirelessly detecting the conductor'"'"'s harmonic response.

Claims

1. A wireless tamper detection sensor, comprising:

at least one electrical conductor having first and second ends and shaped to form a geometric pattern between said first and second ends;

each said conductor in said geometric pattern defining an open-circuit that can store and transfer electrical and magnetic energy;

each said conductor further having perforations formed therethrough wherein electrical conductivity is maintained between said first and second ends thereof;

each said conductor resonating in the presence of a time-varying magnetic field to generate a harmonic response, wherein said harmonic response changes when said conductor experiences a change in said geometric pattern due to severing of said conductor along at least a portion of said perforations.

2. A wireless tamper detection sensor as in claim 1, wherein each said conductor comprises a thin-film trace defining said geometric pattern, further wherein the width of said trace is selected from the group consisting of uniform and non-uniform and the spacing between adjacent portions of said trace is selected from the group consisting of uniform and non-uniform.

3. A wireless tamper detection sensor as in claim 1, wherein said geometric pattern is a spiral.

4. A wireless tamper detection sensor as in claim 1, further comprising a tearable material to which each said conductor with said perforations is coupled.

5. A wireless tamper detection sensor as in claim 4, wherein said tearable material is perforated in correspondence with said perforations in each said conductor.

6. A wireless tamper detection sensor as in claim 1, further comprising a substrate material to which each said conductor with said perforations is coupled, said substrate material being perforated in correspondence with said perforations in each said conductor.

7. A wireless tamper detection sensor as in claim 1, further comprising two layers of tearable materials wherein each said conductor with said perforations is disposed between said two layers.

8. A wireless tamper detection sensor as in claim 7, wherein said two layers are perforated in correspondence with said perforations in each said conductor.

9. A wireless tamper detection sensor as in claim 1, further comprising a layered substrate wherein each said conductor with said perforations is disposed between two layers of said layered substrate and wherein said layered substrate is perforated in correspondence with said perforations in each said conductor.

10. A wireless tamper detection sensor as in claim 1, further comprising a magnetic field response recorder for wirelessly transmitting said time-varying magnetic field and for wirelessly detecting each said harmonic response

11. A wireless tamper detection sensor, comprising:

an electrical conductor having first and second ends and shaped to form a geometric pattern between said first and second ends, said conductor in said geometric pattern defining an open-circuit that can store and transfer electrical and magnetic energy; and

a pattern of perforations formed through said conductor wherein electrical conductivity is maintained between said first and second ends thereof;

said conductor resonating in the presence of a time-varying magnetic field to generate (i) a first harmonic response when said pattern of perforations remains intact wherein said first harmonic response has a first frequency, amplitude and bandwidth associated therewith, and (ii) a second harmonic response when said conductor has been severed along a portion of said pattern of perforations wherein said second harmonic response has a second frequency, amplitude and bandwidth associated therewith that is different than said first frequency, amplitude and bandwidth, respectively.

12. A wireless tamper detection sensor as in claim 11, wherein said conductor comprises a thin-film trace defining said geometric pattern, further wherein the width of said trace is selected from the group consisting of uniform and non-uniform and the spacing between adjacent portions of said trace is selected from the group consisting of uniform and non-uniform.

13. A wireless tamper detection sensor as in claim 11, wherein said geometric pattern is a spiral.

14. A wireless tamper detection sensor as in claim 11, further comprising a tearable material to which said conductor with said pattern of perforations is coupled.

15. A wireless tamper detection sensor as in claim 14, wherein said tearable material is perforated in correspondence with said pattern perforations.

16. A wireless tamper detection sensor as in claim 11, further comprising a substrate material to which said conductor with said pattern of perforations is coupled, said substrate material being perforated in correspondence with said pattern of perforations.

17. A wireless tamper detection sensor as in claim 11, further comprising two layers of tearable materials wherein said conductor with said pattern of perforations is disposed between said two layers.

18. A wireless tamper detection sensor as in claim 17, wherein said two layers are perforated in correspondence with said perforations in said conductor.

19. A wireless tamper detection sensor as in claim 11, further comprising a layered substrate wherein said conductor with said perforations is disposed between two layers of said layered substrate and wherein said layered substrate is perforated in correspondence with said perforations in said conductor.

20. A wireless tamper detection sensing system, comprising:

at least one electrical conductor having first and second ends and shaped to form a geometric pattern between said first and second ends;

each said conductor in said geometric pattern defining an open-circuit that can store and transfer electrical and magnetic energy;

each said conductor further having perforations formed therethrough wherein electrical conductivity is maintained between said first and second ends thereof;

each said conductor resonating in the presence of a time-varying magnetic field to generate a harmonic response, wherein said harmonic response changes when said conductor experiences a change in said geometric pattern due to severing of said conductor along at least a portion of said perforations; and

a magnetic field response recorder for wirelessly transmitting said time-varying magnetic field and for wirelessly detecting each said harmonic response.

21. Sensing tape, comprising:

at least one electrical conductor having first and second ends and shaped to form a geometric pattern between said first and second ends;

each said conductor in said geometric pattern defining an open-circuit that can store and transfer electrical and magnetic energy;

each said conductor further having perforations formed therethrough wherein electrical conductivity is maintained between said first and second ends thereof;

each said conductor resonating in the presence of a time-varying magnetic field to generate a harmonic response, wherein said harmonic response changes when said conductor experiences a change in said geometric pattern due to severing of said conductor along at least a portion of said perforations;

a substrate material, comprising a first surface and a second surface, wherein each said conductor with said perforations is coupled to said first surface and an adhesive is coupled to said second surface.

22. The sensing tape as in claim 21, wherein said substrate material is perforated.

23. The sensing tape as in claim 22, wherein one or more of said substrate perforations correspond with said perforations in each said conductor.

24. The sensing tape as in claim 21, wherein one or more of said substrate perforations are positioned between adjacent conductors.

25. The sensing tape as in claim 21, wherein said harmonic response is dependent on the (i) temperature, resistance, capacitance, and inductance of said at least one conductor;

(ii) the amount of magnetic flux received from an operatively connected magnetic field response recorder;

(iii) the rate of change of said magnetic flux;

(iv) the physical properties of material in said at least one conductor'"'"'s electric field;

(v) the physical properties of material in said at least one conductor'"'"'s magnetic field;

(vi) the amount of material in said at least one conductor'"'"'s electric field; and

, (vii) the amount of material in said at least one conductor'"'"'s magnetic field.