Passive tamper-resistant seal and applications therefor

A radio frequency identification seal comprises an antenna including a main antenna portion and at least one break-away portion and an RFID tag coupled and tuned to the antenna. The RFID tag outputs a signature in response to a scanning signal when tuned to the antenna.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. application Ser. No. 12/081,444 filed on Apr. 16, 2008 now issued under U.S. Pat. No. 8,063,779, the entire disclosure of which is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates generally to tamper-resistant packaging and in particular to a passive tamper-resistant seal and applications therefor.

BACKGROUND OF THE INVENTION

Tamper-resistant packaging is well known in the art. In the pharmaceutical industry, containers holding medicines are designed so that when the contents of the containers are accessed, clear visual indications signifying container access are provided.

In other environments, providing such visual tamper-resistance on containers is difficult. As a result, in these environments manual inspection of containers is required. For example, at border crossings and other inspection points, large containers carried by trucks and ships are typically manually inspected. Containers of this nature generally provide no visual indication signifying if the containers have been opened. This of course slows the inspection process as all containers must be inspected.

U.S. Pat. No. 6,747,558 to Thorne et al. discloses a device for sealing and tracking a container. The device includes a bolt which extends through openings in a latch mechanism on the container. The bolt also passes through spaced coils of the device. The device uses one coil to generate a magnetic field, while monitoring the corresponding magnetic field induced in the other coil. Tampering with the bolt affects the magnetic field, which in turn permits the device to detect the tampering. The device periodically transmits wireless signals which can be remotely received for purposes of tracking the container and monitoring the integrity of the device.

Although the Thorne et al. device allows tampering to be detected, it is complicated and costly to manufacture. As will be appreciated, there exists a need for an improved mechanism that allows secure uncompromised containers to be differentiated from compromised containers.

It is therefore an object of the present invention to provide a novel passive tamper-resistant seal and novel applications therefor.

SUMMARY OF THE INVENTION

Accordingly, in one aspect there is provided a container comprising a container body; and a seal on at least a portion of said container body, said seal including an antenna and a tag tuned to said antenna, said tag becoming detuned when said antenna is compromised during opening of said container.

In one embodiment, the tag outputs a signature in response to a scanning signal when tuned to the antenna. In particular, the tag resonates in response to the scanning signal when tuned to the antenna and outputs a code unique to the tag. The scanning signal is of a predetermined frequency.

The antenna includes a main antenna portion and at least one break-away portion coupled to the main antenna portion. The at least one break-away portion separates from the main antenna portion when the container is compromised resulting in the tag becoming detuned from the antenna. The at least one break-away portion is coupled to the main antenna portion by one-time break-away contacts.

In one embodiment, the main antenna portion is provided on a door of the container and wherein the at least one break-away portion is provided on a doorjamb of the container.

In another embodiment, the tag and antenna are disposed on a substrate adhered to the container.

According to another aspect there is provided a radio frequency identification seal comprising an antenna including a main antenna portion and at least one break-away portion; and an RFID tag coupled and tuned to said antenna, said RFID tag outputting a signature in response to a scanning signal when tuned to said antenna.

The radio frequency identification seal provides advantages in that a determination can be made as to whether a container has been compromised simply by scanning the RFID seal with a scanning signal of the appropriate frequency. If the container has not been compromised, the RFID seal outputs a unique code in response to the scanning signal. If the container has been compromised resulting in one or more break-away portions being separated from the main antenna portion, the RFID seal will not output the unique code in response to the scanning signal thereby clearly to identify the container as being compromised.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Turning now toFIGS. 1 and 2, a passive radio frequency identification (RFID) seal used to secure a container, box, carton or other enclosure is shown and is generally identified by reference numeral10. As can be seen, in this embodiment the RFID seal10is generally rectangular and is sandwiched between a pair of cover sheets14. The outer surfaces of the cover sheets14are covered by one time peal-off labels16. Removal of the labels16exposes high-tack adhesive allowing the RFID seal10to be secured to the container.

As can be seen inFIG. 2, the RFID seal10includes an inner printed electronic layer20formed of Kapton-Polymide film. The inner electronic layer20is sandwiched between intermediate layers22formed of radiolucent conductive spliced polyester/fluoropolymer film. Surrounding the intermediate layers22are outer vinyl gel-foam layers24. The intermediate and outer layers22and24encapsulate the inner layer20. Thus the inner electronic layer20is contained from ecological conditions outside the RFID seal10.

The printed electronic layer20includes an RFID tag26and an antenna28generally taking the shape of a triangle. The antenna28is formed using fine German silver wire and comprises a main shielded antenna portion30and a break-away portion32coupled to the main antenna portion30by one-time, break-away contacts34.

The RFID tag26is tuned to the antenna28so that when the RFID tag26is scanned by a signal at a predetermined frequency and the antenna28is intact, the RFID tag26resonates causing the RFID tag26to output a code unique to the RFID tag26.

During installation of the RFID seal10on a container such as a cargo container36, one of the labels16is removed from the RFID seal10and the RFID seal10is adhered to the inner leading edge of the container door38as shown inFIG. 3a. Once the container36has been loaded, the other label16is removed from the RFID seal10and the container door38is closed and pushed tight until the door touches the doorjamb40as shown inFIG. 3b. In this manner, the RFID seal10becomes adhered to both the container door38and the container body. The outer gel-foam layers24help to take up any variances between the door38and the doorjamb40, when the door38is closed.

When the door38is opened, the one-time contacts34break, thereby, isolating the break-away antenna portion32from the main antenna portion30. In this case, if the RFID tag26is scanned by a signal at the predetermined frequency, the RFID tag will not resonate as the tuning between the antenna28and the RFID tag26is lost. Hence the RFID tag26will not output the unique code. As will be appreciated, the RFID seal10allows an inspector to determine very quickly whether the container36has been compromised. If the container36is packed and sealed at a secure location, scanning the container36to determine if the RFID tag26outputs the unique code at border crossings and/or other inspection points allows an inspector to determine quickly whether the container10requires inspection.

Although the RFID seal10is described above as having an antenna28that is generally triangular in shape, other antenna configurations are possible.FIGS. 4aand4bshow two alternative electronic layer designs including different shaped antennas28and different break-away contact locations. Also, the RFID seal10need not be rectangular in shape. The RFID seal10may take on any convenient geometric shape such as square, circular, triangular etc.

Turning now toFIGS. 5 and 6, a container50including an alternative embodiment of an RFID seal is shown. As can be seen, container50in this embodiment includes a generally rectangular container body52having a door54at one end. The door54is hinged to the container body52allowing the door to swing between open and closed positions. A lock56is provided on the door54to allow the door to be locked in the closed position.

Similar to the previous embodiment, the RFID seal60includes an RFID tag62and an antenna64. The antenna64is formed using fine German silver wire and comprises a main antenna portion66and a break-away portion68coupled to the main antenna portion66by one-time, break-away contacts70. The main antenna portion66in this embodiment is latticed throughout the door54. The break-away portion68is adhered to the container body52at the doorjamb.

When the door54is opened, the one-time contacts70break, thereby, isolating the break-away antenna portion68from the main antenna portion66. Thus, if the RFID tag62is scanned by a signal at the predetermined frequency, the RFID tag will not resonate as the tuning between the antenna64and the RFID tag62is lost. Hence the RFID tag62will not output the unique code.

During installation of the RFID seal60, the RFID tag62is tuned to the antenna64with the break-away antenna portion68free of the container doorjamb and coupled to the main antenna portion66. Once the RFID tag62has been tuned, the break-away antenna portion68is removed from the main antenna portion66and is adhered to the doorjamb of the container body52. The container50is then loaded with goods to be transported. Once the container50has been loaded, the door54is closed and locked. The one-time contacts70are then formed between the main antenna portion66and the break-away antenna portion68to complete the antenna64. The RFID tag62is then scanned to confirm that the RFID tag outputs the unique code signifying that the RFID tag remains tuned to the antenna64.

FIG. 7shows another embodiment of a container110including an RFID seal120comprising an RFID tag122and an antenna124. In this embodiment, the antenna124includes, a main antenna portion124, a break-away antenna portion128aon the doorjamb of the container body112as well as a break-away antenna portion128badjacent the lock116. The break-away antenna portions128aand128bare coupled to the main antenna portion124by one-time, break-away contacts130. When the door114is opened, one or both break-away antenna portions128aand128bseparate from the main antenna portion126via the one-time contacts130. As a result, the RFID tag122becomes detuned and hence does not output the unique code when scanned.

FIG. 8shows yet another embodiment of a container210including a container body212, a door214and a plurality of RFID seals220similar to the RFID seal10shown inFIGS. 1 and 2. As can be seen, in addition to the door214, the top, sides and bottom of the container body212include RFID seals220.

Although the above embodiments show the RFID seals used to secure containers, those of skill in the art will appreciate that the RFID seals may be used to secure other containment devices. For example,FIG. 9shows a transport truck300hauling a trailer302having containers310thereon. Each container310has a door314including an RFID seal320of the type shown inFIGS. 5 and 6.FIG. 10shows other vehicles having storage capabilities on which RFID seals can be mounted.

In situations where the RFID seals are used on trucks and/or other vehicles, stations such as that shown inFIG. 11amay be used to check the integrity of the RFID seals. In this case, RFID reader antennae350are mounted on a frame structure352through which trucks and vehicles pass allowing RFID seals carried by the trucks and vehicles to be read. The results of the RFID seal reads in this embodiment are transmitted by a wireless transmitter354mounted on the frame structure352to a central location356for verification.

RFID reader antennae350may also be placed on highway entrance structures, main roadway lighting poles and entrances/exits to trucking marshalling yards where containers are transferred between vehicles in order to check the integrity of the RFID seals220during transport. For example, as shown inFIG. 11b, the RFID reader antenna350is mounted on a roadway structure360through which trucks and vehicles pass allowing the RFID seals220on the trucks and vehicles to be read. The results of the RFID seal reads are similarly transmitted by a wireless transmitter354to a central location356for verification. Typically, RFID reader antennae350are mounted on various structures over a coverage area and communicate with the central location356. The RFID reader antennae350collectively monitor RFID seals220on vehicles passing through the coverage area to allow container intrusions within the coverage area to be detected quickly.

FIGS. 12aand12bshow a container410in the form of a box or a carton including an RFID seal420. In this embodiment, the box410is rectangular or square box and has a seam412separating the two flaps414defining the top of the box. The RFID seal420in this case includes a substrate421that is adhered to the top of the box410and spans the seam412. An RFID tag422and an antenna424are also adhered to the substrate421. The RFID tag422is pre-tuned to the antenna424. The antenna424includes a main antenna portion426and a plurality of break-away antenna portions428a,428band428cat spaced locations along the length of the antenna424. The break-away antenna portions428a,428band428care coupled to the main antenna portion426by one-time break-away contacts430. Two of the break-away antenna portions428aand428bspan the seam412. In this manner, when the box410is opened along the seam412and the RFID seal420is torn, one or more of the break-away antenna portions428a,428band428cseparate from the main antenna portion426via the one-time break-away contacts430. As a result, the RFID tag422becomes detuned and thus, provides no output when scanned at the predetermined frequency.

Although the above-embodiment shows the RFID seal being used to secure a square box by engaging the flaps of the box, those of skill in the art will appreciate that the RFID seal may be used to secure other box or carton configurations. For example,FIGS. 13,14aand14bshow other containers incorporating RFID seals. In the embodiments ofFIGS. 14aand14b, RFID seals are used to secure retail store merchandise that has been repackaged, rewrapped or re-boxed within the retail store. The customer or reseller can thus, ensure that the merchandise has not been tampered with. In the embodiments ofFIGS. 12,13,14aand14b, the break-away antenna portions of the RFID seal antennae need not engage the boxes or cartons. Rather, the break-away antenna portions can be incorporated into packing material placed into the boxes or cartons as shown inFIGS. 15aand15b. In these cases, the break-away antenna portions are coupled to the main antenna portions on the containers so that when the containers are opened, the break-away antenna portions separate from the main antenna portions resulting in the RFID seals becoming detuned.

As will be appreciated, in the above-described embodiments, the RFID seals allow containers to be inspected to determine if a container has been compromised quickly and easily simply by scanning the RFID seals with a signal at the appropriate frequency. Containers whose RFID seals do not output a unique code in response to the scanning signal are immediately recognized as having been tampered with. Decisions to inspect containers can thus be made quickly and accurately increasing the efficiency of inspection points such as border crossings.

While specific examples of containers are shown, those of skill in the art will appreciate that the containers may take virtually any form. Also, while specific reference is made to RFID seals, those of skill in the art will appreciate that other types of passive seals that can be tuned to an antenna and are responsive to scanning signals can of course be used. Furthermore, the RFID seals may be used in other environments to allow access or intrusion to be detected.

For example,FIG. 16shows RFID seals220used to secure an airplane370. As can be seen, the RFID seals220are attached to the outer shell or fuselage of the airplane370at access points such as linkages, undercarriage housings, viewing/maintenance access panels, non-access hatches and emergency doors. The RFID seals220are affixed to the aircraft in the manner described previously such that when, for example, an emergency door is opened, the break-away antenna portions separate from the main antenna portion via the one-time break-away contacts. As a result, the RFID seals220become detuned thus, providing no output when scanned at the predetermined frequency. Those of skill in the art will appreciate that use of the RFID seals is not limited to aircraft and that the RFID seals may be affixed to virtually any type of vehicle. For example, RFID seals220may also attached to the hatch ways, hatch covers and protective housing lids of a boat or cargo shipping vessel.

While the above examples show the use of RFID seals to secure containers of various forms, vehicles, aircraft etc. to provide an indication of access or intrusion, the RFID seals may also be used in alternative environments. For example, the RFID seals may be applied to structure materials and used to detect failure in structural materials. As shown inFIG. 17, an RFID seal500is affixed to a structural material502via a substrate at a location prone to fatigue. Fatigue may take the form of cracks that may lead to dislocation and slow structure separation, protrusions, chevron buckling, hair-line fractures, corrosion notching, skin notching and skin stiffness. In this embodiment, the substrate is coated polyvinylidenefluoride (PVDF) which ruptures at 0.03% strain. When the substrate ruptures as a result of fatigue of the structure material502, the one-time break-away contacts break, thereby isolating the break-away antenna portion from the main antenna portion as previously described. Thus, when the RFID seal500is scanned by a scanning signal at the predetermined frequency, the RFID seal does not resonate and does not output a signature allowing failure in the structural material502to be detected.

FIGS. 18aand18bshow the RFID seal500applied to the inside of a pressure pipe504at a location prone to failure and a failure in the pressure pipe504at the location of RFID seal application.

Although a specific substrate form is described, those of skill in the art will appreciate that alternatives are available. In another embodiment, the substrate is formed of a rigid ceramic or mica having a thickness of about 0.5 to 1.00 mm that is covered with a protective coating layer. The substrate in this embodiment ruptures in response to fatigue in the structural material causing the one-time break-away contacts to break and detune the RFID seal. In yet another embodiment, the substrate is formed of elastomeric, polyamide or acryl-nitric material. As will be apparent the substrate material that is selected depends on the ecological conditions of the application. Also, the substrate need not rupture but rather may be formed of a material that stretches or elongates in response to structural material fatigue resulting in breaking of the one-time break-away contacts and detuning of the RFID seal.

As will be appreciated by those of skill in the art, in certain cases, fatigue may be not be visible with the naked eye. Use of RFID seals allows such structural fatigue to be detected early and inexpensively obviating the need for expensive ultrasonic scanning devices.

RFID tag scanning may be performed locally using a hand-held reader or as shown inFIG. 19, using a networked scanning system600. System600comprises RFID readers602which output scanning signals to RFID seals affixed to structural material604. In response, the RFID seals output signatures if no failure is present at their locations when scanned by the readers602. The readers602transmit the read signatures to a fixed repeater terminal606that transmits the signatures to a monitoring station608over a communications links such as for example the Internet or other suitable wired or wireless network. The monitoring station608transmits instructions to the repeater terminal606which in turn instructs the readers602to output scanning signals to the scan the RFID seals on the structural material604. Thus, system600allows for polling of RFID seals to track failure in structural material604.

As shown inFIGS. 20 to 22, RFID seals500can be used to detect failures on airplanes510. InFIG. 21, RFID seals500are shown strategically placed internally throughout the frame of an airplane510at extreme stress locations, e.g. wings, fuselage, tail, landing gear, longerons (stringer or stiffener), spars and ribs. As shown inFIGS. 21 and 22, RFID seals500are placed at strategic stress locations to detect failure on light airplanes512as well as on undercarriages514of aircraft.

As shown inFIG. 23, RFID seals500may also be used to detect failures on cranes516. In this application, RFID seals500are placed at stress points on the crane, e.g. boom, main trunnion support, counterweight, welding points, welding points, and lifting harness.

As shown inFIG. 24, RFID seals500may also be used to detect failures on a bridge518. In this application, RFID seals500are placed at possible failure points of the bridge, e.g. main spans, pad bearings, parapets, expansion joints, road decking.

As shown inFIG. 25, RFID seals500may also be used to detect failures on drilling rigs520for off-shore oil/gas drilling. In this application, RFID seals500are affixed to the submersible supports of the drilling rig520which are exposed to waves as well as to atmospheric conditions that may cause failure due to corrosion and resulting destructive structural erosion.FIG. 26show corrosion on one of the submersible supports of the drilling rig520and resulting fatigue. RFID seals may also be affixed to bridge footings and bridge/pier fastening, strapping and anchors where corrosion may also occur.

As shown inFIG. 27, RFID seals500may also be used to detect failures in boilers522and fuel rod casements524in nuclear power plants. These areas are in hazardous high radiation zones and cannot be inspected visually without significant personal protective equipment which is time and cost expensive. The RFID seals500allow for failure detection without requiring visual inspection.

As shown inFIG. 28, RFID seals500may also be used to detect failures on railway dolly assemblies526at possible fatigue points rather than relying on the conventional and subjective testing method that involves striking the wheel of the railway dolly assembly to detect a failure by noting changes in the resulting vibration tone.

As shown inFIG. 29, RFID seals500may also be used to detect failure on wind turbines528. In this application, RFID seals500are placed on the wind generators at failure points such as those which are subject to low-frequency fatigue strain creep caused by piezo-effect noise, e.g. blades, spindles and stanchions.

As shown inFIG. 30, RFID seals500may also be used to detect failures on shipping vessels530with single or double skins.

The RFID seals may also be used for failure detection in structural material testing. In material testing, failure may be caused by overheating, compression, torsion or tension impact loads. During testing of non-ferrous ductile materials such as, aluminum, copper and plastics, materials may return partially or wholly to their original shapes and thus, failure may not be detected after testing. In impacts involving more brittle ferrous materials, e.g. cast iron, spherulitic graphite (SG) cast iron, hardened steel, high strength alloys, ceramics and armor-toughened glass, the failure is typically evident but such is not always the case in impacts involving ductile materials. Affixing RFID seals to these ductile materials prior to testing enables testers to monitor structural failures in ductile materials.

As shown inFIGS. 31aand31b, RFID seals500may also be affixed to products540for brand and product protection. In this application, RFID seals500are affixed to products540to ensure consumers are purchasing genuine goods and goods that have not been tampered with. If the product has been tampered with, the RFID seal will become detuned and will not transmit a signature when scanned by an RFID reader. Furthermore, if the product is a counterfeit, the counterfeit product will not carry an RFID seal so no signature will be transmitted when scanned by the RFID reader.

FIG. 32shows the steps of an RFID seal reading methodology. The method700of authenticating a product begins when a user launches a brand recognition application on an electronic device that has an RFID reader (step702). The user then scans a product with the electronic device such that the RFID reader transmits a scanning signal at a predetermined frequency (step704). In response, the RFID seal on the product transmits a signature if the RFID seal is intact (step706). If no signature is received by the RFID reader then the application outputs a message signifying that the product is not authentic or has been tampered with (step708). If the RFID reader receives a signature, the signature is sent to the manufacturer to obtain an encryption key (step710). Upon receiving the signature, the manufacturer determines the encryption key and sends the key and a token back to the electronic device (step712). The electronic device then attempts to decrypt a portion of the signature using the decryption key (step714). The electronic device determines if the token transmitted by the manufacturer matches the decrypted portion of the signature (step716). If the token and the decrypted portion of the signature do not match, the device displays a message that the product is not authentic (step718). If the token and the decrypted portion match, the device displays a message that the product is authentic (step720).

As shown inFIG. 33, an authentication gateway750to which the signature is first transmitted from the electronic device754after scanning the product752may be employed. In this case, the signature from the electronic device includes manufacturer data, product data as well as the encrypted data. The authentication gateway750determines the manufacturer (via a look-up table) from the manufacturer data then transmits the product data to the manufacturer756. The manufacturer756retrieves the encryption key and the token based on the product data (via a look-up table) and transmits these two to the authentication gateway750. The authentication gateway750then transmits the encryption key and token to the electronic device754as described above.

In the embodiments above, the RFID seals are described and shown to be discrete. RFID seals may however be bundled to provide an indication as to the extent of loading or deformation of the support on which the RFID seals are mounted. For example, as shown inFIGS. 34 and 35, the RFID seals800may be affixed to a substrate in the form of a ribbon802with the various RFID seals800being designed to become detunded at different tensile loads. The super heavyweight RFID seal800requires a greater tensile load to be placed thereon before the break-away antenna portion thereof separates from the main antenna portion than the heavyweight RFID seal800and this follows in descending order for the other RFID seals800(light heavyweight, middleweight, welterweight, lightweight and featherweight). The ribbon802in this embodiment is a continuous strip of material formed for example of PVDF or other suitable material. If the ribbon802is formed of rigid ceramic or mica then individual tablets are used for each RFID seal800that have different tensile load detuning points. The individual tablets are aligned side by side and are of appropriate thicknesses so that the RFID seals detune at the proper tensile loading point.

As the tensile load applied to the ribbon increases from zero, the ribbon802undergoes elongation of about 0.01% to 14.00%. As this happens, the various RFID seals will become detuned in graduated order with the featherweight RFID seal becoming detuned first followed by the lightweight RFID seal, then the welterweight RFID seal, then the middleweight RFID seal, then the light heavyweight RFID seal, then the heavyweight RFID seal and finally the super heavyweight RFID seal.

The RFID seals become detuned at various tensile loads due in part to the substrate type and antenna coating of each RFID seal800. The substrate may range in density from about 0.97 to 1.27 g/mol. The antenna is vacuum formed on the substrate. As previously described, the substrate used may be PVDF flouropolymer or individual tablets of ceramic or mica that rupture depending on thickness. Other substrates are possible and may be determined in accordance with the design considerations known in the art e.g. type, thickness, density, elongation rupture, tensile strength, flexural strength, young's elastic modulus, coefficient thermal stability, dielectric constant and glass temperature.

In one embodiment, the antenna coating is formed of Parylene UV and Acrylic Tollcoat and the substrate is a tablet of ceramic or mica. In another embodiment, the substrate is an oxide, alumina or ceria or a non-oxide, carbide or silicide. In another embodiment, the substrate is formed of a polyamides, polyethylene, acrylonitrile, polyvinyl ‘c’, polysulfone, polyetherimide or elastomeric material. In another embodiment, attaching epoxies are used, e.g. silicones, aluminum filled induction cured epoxy, thermal sink compounds and magnetic bonding epoxies, to attach the RFID seals800to the surface depending on the application.

In other embodiments, the substrate is sheet-layer plastics of varying density or ceramics known in the art that is suitable for particular high temperature application and that achieve the different tensile load detune points. The antenna is manufactured from magnesium, cadmium copper, tin, aluminum, nickel, nickel/copper alloy, silver, gold, platinum, chromium, liquid gallium or liquid gallistan.

The ribbon802may be used to detect the tensile load placed on structures. As shown inFIG. 36, the ribbon802is affixed to expansion control joints804. As the tensile load applied to separate or bring together the expansion controls joints804increases depending on the magnitude of the tensile load, one or more of the RFID seals800on the ribbon802will become detuned and will cease transmitting unique signatures when scanned at the predetermined frequencies. Thus, a reader can detect the movement of the expansion control joints804and the extent of the tensile load placed on the expansion control joints based on the number of RFID seals of the ribbon that respond to scanning signals. The ribbon802may be applied to bridges, arches, carrying beams and structural central loads in longitudinal or transverse orientation.

A handheld reader may be used to detect the increasing tensile loads applied to the ribbon802. Maintenance crew may therefore survey the expansion control joints804by scanning the joints804with a reader that transmits scanning signals at the various predetermined frequencies for the RFID seals800.

As shown inFIGS. 37aand37b, the ribbon802may also be used to detect movement in other surfaces. For example, the ribbon802may be affixed to a cord806which is pulled taut between stakes808. In the event of movement of the stakes, tension is applied to the cord806and the resulting elongation or compression, may result in one or more of the RFID seals800becoming detuned depending on the magnitude of the applied tension.

The ribbon802may also be placed on the cross-ties812of a scissor mechanism814as shown inFIG. 38. The cord306is a rigid member affixed to the scissor mechanism814. The scissor mechanism814has springs816holding the mechanism814in a particular orientation. The cross-ties812extend perpendicular to the springs816. When the cord806is compressed, the springs816compress which elongates the cross-ties812and detunes at least some of the RFID seals800on the ribbon802.

InFIGS. 37aand37b, the scanning signals are transmitted by a polling station810at the various predetermined frequencies. The results of the scanning, detection of the signature or not, are then transmitted to a central processing site via the internet or other wired or wireless communication network. Handheld scanning may also be performed in the manner already described.

FIG. 39shows the cord and stakes employed to detect seismic movement in the earth's crust associated with earthquakes.FIG. 40shows the cord and stakes employed to detect avalanches whileFIG. 41shows the cord and stakes employed to detect landslides.

In another embodiment, the ribbon802may be used to measure heat expansion and contraction in structures in high electromagnetic interference (EMI) environments (e.g. industrial/scientific facilities and nuclear power stations) or other environments as shown inFIG. 42. The RFID seals800on the ribbon are separated by individual readers850which scan the individual RFID seals800to detect the signature of RFID seals800. If extensive expansion or contraction of a structure to which the ribbon is affixed occurs, one or more of the RFID seals800of the ribbon will become detuned depending on the amount of expansion or contraction. The readers850transmit signatures output by the RFID seals external to the high EMI environment via a protected cable to a polling station810. The signatures can then be processed at the polling station810or transmitted to another location for further processing.

In another embodiment, the readers850are shielded to protect them in the EMI environment with shielded coaxial cable and the signatory from the readers850are transmitted to the polling station810via a shielded coaxial cable.

Although embodiments have been described, those of skill in the art will appreciate that variations and modifications may be made without departing from the scope thereof as defined by the appended claims.