Sensing System and Method

• US 20130139596A1
• Filed: 05/16/2011
• Published: 06/06/2013
• Est. Priority Date: 05/14/2010
• Status: Active Grant

• Current Assignee: Investech Partners Investments, LLC
• Original Assignee: Paramata Ltd.
• Inventors: Lowe, Christopher Robin, Stevenson, Adrian Carl, Jain, Karishma
• Granted Patent: US 9,726,618 B2
• Time in Patent Office: Days
• US Class Current: 73/582
• CPC Class Codes: G01N 22/02 Investigating the presence of flaws
• CPC Class Codes: G01N 33/442 Resins, plastics

Abstract

A sensing system which comprises a material (30) formed of a matrix and a plurality of non-insulating particles (40) substantially equally spaced within the matrix such that the material has coherent electrical periodicity in at least one dimension; and a receiver (10), the receiver arranged to receive a source RF signal and a returned RF signal, the source RF signal being reflected by the non-insulating particles to produce the returned RF signal. A change in the position of one or more of the non-insulating particles causes the returned RF signal to change, such that a change in a property of the material can be determined from the returned RF signal.

Claims

1. A sensing system comprising:

a material comprising a matrix and a plurality of non-insulating particles substantially equally spaced within the matrix such that material has coherent electrical periodicity in at least one dimension; and

a receiver arranged to receive a source RF signal and a returned RF signal, the source RF signal being reflected by the non-insulating particles to produce the returned RF signal;

wherein a change in the position of one or more of the non-insulating particles causes the returned RF signal to change, such that a change in a property of the material can be determined from the returned RF signal.

2. The system according to claim 1 wherein the matrix is a non-conductive matrix and the non-insulating particles are conducting particles.

3. The system according to claim 2, wherein the conductive particles include at least one of carbon particles, carbon fibre, graphenes, aluminium particles, silver particles, copper particles, gold particles, and carbon nanotubes.

4. The system according to claim 1, wherein the non-insulating particles are semiconducting particles.

5. The system according to claim 1, wherein the non-insulating particles are composite particles comprising a metal and an insulator.

6. The system according to claim 1, wherein the matrix comprises a polymer.

7. The system according to claim 6, wherein the matrix comprises at least one of a thermosetting epoxy, thermoplastic polyester, vinyl ester or nylon.

8. The system according to claim 1, wherein the material has a coherent periodic conductivity in at least one dimension.

9. The system according to claim 1, wherein the material has a coherent periodic dielectric constant in at least one dimension.

10. The system according to claim 1, wherein a change in the returned RF signal is any of a change in amplitude, a change in frequency, a phase-shift, or a change in interference effects.

11. The system according to claim 1, wherein the change in a property of the material is any of a particle break, a microcrack, a delamination, a contaminant, matrix impact damage, or a change in porosity.

12. The system according to claim 1, wherein the receiver is arranged to receive ambient RF signals.

13. A method of sensing a change in a property of a material, the material comprising a matrix and a plurality of non-insulating particles substantially equally spaced within the matrix such that the material has coherent electrical periodicity in at least one dimension, the method comprising the steps of

interrogating the material with a source RF signal;

receiving a returned RF signal reflected from the non-insulating particles; and

determining the change in the property of the material from a change in the returned RF signal that is caused by a change in the position of one or more of the non-insulating particles.

14. The method according to claim 13, wherein interrogating the material comprises scanning the surface of the material using a single mechanical probe.

15. The method according to claim 13, wherein interrogating the material comprises scanning the surface of the material with an electronic multiple probe along a 1D or 2D path.

16. The method according to claim 13, wherein interrogating the material comprises exciting the material as though it was an antenna to generate a surface field profile.

17. The method according to claim 16, wherein interrogating the material further comprises scanning the surface field profile using a single mechanical probe.

18. The method according to claim 16, wherein interrogating the material further comprises scanning the surface field profile using an electronic multiple probe.

19. The method of claim 16, wherein interrogating the material further comprises scanning the surface field profile is a 2D probe array with electronic switching or multiple signal channels.

20. The method according to claim 19, further comprising placing the 2D probe array in a flexible probe sheet.

21. The method according to claim 13, wherein the source RF signal is modulated.

22. The method according to claim 13, wherein the material is obtained by doping a semiconductor material to achieve the coherent electrical periodicity.

23. The method according to claim 13, wherein the material comprises a plurality of cells and wherein each cell represents an antenna element.

24. The method according to claim 23, wherein the plurality of cells are coupled and form a cell array.

25. The method according to claim 24, wherein the plurality of cells coupled via induced modulated RF currents.

26. The method according to claim 19, wherein the 2D probe array comprises at least one high impedance probe.

27. The method according to claim 26, wherein the at least one high impedance probe comprises a plurality of metal micro-elements.

28. The method according to claim 26, wherein the at least one high impedance probe is a diode rectifier or a gate of a field effect transistor.

29. The method according to claim 13, wherein the returned RF signal is received by a homodyne receiver.

30. The method according to claim 13, wherein interrogating the material comprises introducing an electromagnetic field mode within the material and wherein receiving the returned RF signal comprises detecting a surface evanescent electromagnetic field of the material.

31. The method according to claim 23, wherein the plurality of cells form a wireless cellular network.

32. The method or system according to claim 13, wherein determining the change in the property of the material comprises 2D or 3D imaging of the composite material.

33. The method or system according to claim 13, wherein determining the change in the property of the material comprises detecting an anisotropic conductivity of the material.

34. The method or system according to claim 13, wherein the property of the material is crystallinity.

35. (canceled)