SENSING SYSTEM AND METHOD

• US 20120007607A1
• Filed: 11/28/2008
• Published: 01/12/2012
• Est. Priority Date: 11/30/2007
• Status: Active Grant

• Current Assignee: Investech Partners Investments, LLC, Cambridge Enterprise Limited (University of Cambridge), Chancellor Masters & Scholars of The University of Cambridge (University of Cambridge)
• Original Assignee: Cambridge Enterprise Limited (University of Cambridge)
• Inventors: Lowe, Christopher R., Stevenson, Adrian, Tannock, Quentin, Jain, Karishima
• Granted Patent: US 8,736,281 B2
• Time in Patent Office: Days
• US Class Current: 324/639
• CPC Class Codes: G01D 5/12 using electric or magnetic means G01D5/06 takes precedence
• CPC Class Codes: G01D 5/16 by varying resistance
• CPC Class Codes: G01M 5/0033 by determining damage, crack or wear
• CPC Class Codes: G01M 5/0083 by measuring variation of impedance, e.g. resistance, capacitance, induction
• CPC Class Codes: G01N 2011/0066 electrical properties
• CPC Class Codes: G01N 2011/0073 acoustic properties
• CPC Class Codes: G01N 22/02 Investigating the presence of flaws
• CPC Class Codes: G01N 35/00871 Communications between instruments or with remote terminals
• CPC Class Codes: H04Q 2209/40 using a wireless architecture
• CPC Class Codes: H04Q 2209/845 where the measuring is synchronized between sensing devices
• 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 sensing system comprises a material having a matrix structure in which a plurality of sensing elements are embedded, the sensing elements having electron distribution and/or transport properties that change in response to a change in a physical or chemical property of the material. The sensing system further comprises a receiver, including an antenna, the receiver arranged to receive a source RF signal and a returned RF signal, the returned RF signal being received from the material. A change in the electron distribution and/or transport properties of the sensing elements cause the source RF signal to change, such that a change in a property of the material can be determined from the returned RF signal. A corresponding method of sensing a change in a property of a material is also provided.

Claims

1. A sensing system comprising:

a material having a matrix structure in which a plurality of sensing elements are embedded, the sensing elements having electron distribution and/or transport properties that change in response to a change in a physical or chemical property of the material; and

a receiver, including an antenna, the receiver arranged to receive a source RF signal and a returned RF signal, the returned RF signal being received from the material;

wherein a change in the electron distribution and/or transport properties of the sensing elements cause the source RF signal to change, such that a change in a property of the material can be determined from the returned RF signal.

2. The sensing system according to claim 1, wherein the sensing elements are arranged to alter dielectric properties of the material.

3. The sensing system according to claim 1, wherein the sensing elements are arranged to alter magnetic properties of the material.

4. The sensing system according to claim 1, wherein the sensing elements include nanoparticles comprising at least one of single wall carbon nanotubes, multiwall carbon nanotubes, gold nanorings, magnetic nanoparticles, nanowires and spherical nanoparticles.

5. The sensing system according to claim 1, wherein the sensing elements include pores.

6. The sensing system according to claim 1, wherein the sensing elements comprise particles, the resonance frequency of which is changed by a change in an electrical and/or mechanical property of the material.

7. The sensing system according to claim 6, wherein the sensing elements comprise particles that cause the change in the source RF signal via magnetostriction, converse piezoelectricity, magnetic direct generation or electron coupling, such that resonance is induced in the returned RF signal.

8. The sensing system according to claim 1, wherein the sensing elements comprise particles, the resonance Q factor of which is changed by a change in an electrical and/or mechanical property of the material.

9. The sensing system according to claim 1, wherein the sensing elements are arranged, upon interaction with the source RF signal, to generate harmonic frequencies of the source RF sign al in the returned RF signal.

10. The sensing system according to claim 1, wherein the material comprises a polymer.

11. The sensing system according to claim 1, wherein the material comprises a nanocomposite material.

12. The sensing system according to claim 11, wherein the material comprises an elastomer or epoxy matrix.

13. The sensing system according to claim 1, wherein the sensing elements are substantially equally spaced within the material.

14. The sensing system according to claim 1, wherein the change in the property of the material is in response to an environmental change, the environmental change being a change in stress, strain, temperature, pH, hydration, volume distortion, density fluctuations, contamination, radiation or icing of the material.

15. The sensing system according to claim 1, wherein the radio signal generated by the transceiver is pulse, frequency, phase or digitally modulated.

16. The sensing system according to claim 1, further comprising:

at least one transmitter, wherein the at least one transmitter is arranged to transmit a source RF signal.

17. The sensing system according to claim 16, wherein the sensing system is arranged to determine an amplitude ratio between the returned RF signal at twice the frequency of the source RF signal generated by the transmitter, in order to monitor local interactions between the sensing elements.

18. The sensing system according to claim 16, wherein the source RF signal is arranged to heat a site of the material at which the change in the property of the material is determined.

19. The sensing system according to claim 1, wherein the antenna comprises a directional antenna.

20. The sensing system according to claim 1, wherein the antenna comprises one of a parabolic or a phase array antenna structure.

21. The sensing system according to claim 16, wherein the antenna is arranged to direct the source RF signal towards a predetermined target site of a structure comprising the material.

22. The sensing system according to claim 1, wherein the sensing system further comprises circuitry arranged to determine at least one of the mechanical, electrical and chemical status of the material.

23. The sensing system according to claim 1, wherein the sensing system is arranged to determine a resonance frequency of the material as a function of time.

24. The sensing system according to claim 16, wherein the sensing system is arranged to combine the returned RF signals from the at least one source RF signals in order to obtain spatial information in respect of the material.

25. A method of sensing a change in a property of a material, the material having a matrix structure in which a plurality of sensing elements are embedded, the sensing elements having electron distribution and/or transport properties that change in response to a change in a physical or chemical property of the material, the method comprising the steps of:

interrogating the material with a source RF signal;

receiving a returned RF signal from the material; and

determining the change in the property of the material from a change in the returned RF signal that is caused by the change in the electron distribution and/or transport properties of the sensing elements.

26. The method of claim 25, further comprising the step of generating a source RF signal.