WO2011019311A1 - Procédé et dispositif à des fins d’identification - Google Patents

Procédé et dispositif à des fins d’identification Download PDF

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Publication number
WO2011019311A1
WO2011019311A1 PCT/SE2010/000203 SE2010000203W WO2011019311A1 WO 2011019311 A1 WO2011019311 A1 WO 2011019311A1 SE 2010000203 W SE2010000203 W SE 2010000203W WO 2011019311 A1 WO2011019311 A1 WO 2011019311A1
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WO
WIPO (PCT)
Prior art keywords
scattering
magnetic element
magnetic field
alternating
magnetic
Prior art date
Application number
PCT/SE2010/000203
Other languages
English (en)
Inventor
Carl Tyrén
Original Assignee
Sarci Ag
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sarci Ag filed Critical Sarci Ag
Priority to EP10808422A priority Critical patent/EP2465103A1/fr
Publication of WO2011019311A1 publication Critical patent/WO2011019311A1/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/74—Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems
    • G01S13/75—Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems using transponders powered from received waves, e.g. using passive transponders, or using passive reflectors
    • G01S13/751—Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems using transponders powered from received waves, e.g. using passive transponders, or using passive reflectors wherein the responder or reflector radiates a coded signal
    • G01S13/753—Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems using transponders powered from received waves, e.g. using passive transponders, or using passive reflectors wherein the responder or reflector radiates a coded signal using frequency selective elements, e.g. resonator
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/74—Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems
    • G01S13/75—Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems using transponders powered from received waves, e.g. using passive transponders, or using passive reflectors
    • G01S13/751—Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems using transponders powered from received waves, e.g. using passive transponders, or using passive reflectors wherein the responder or reflector radiates a coded signal
    • G01S13/756—Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems using transponders powered from received waves, e.g. using passive transponders, or using passive reflectors wherein the responder or reflector radiates a coded signal using a signal generator for modifying the reflectivity of the reflector
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V15/00—Tags attached to, or associated with, an object, in order to enable detection of the object
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K19/00—Record carriers for use with machines and with at least a part designed to carry digital markings
    • G06K19/06—Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code
    • G06K19/067—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components
    • G06K19/07—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips
    • G06K19/0723—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K19/00—Record carriers for use with machines and with at least a part designed to carry digital markings
    • G06K19/06—Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code
    • G06K19/067—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components
    • G06K19/07—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips
    • G06K19/077—Constructional details, e.g. mounting of circuits in the carrier
    • G06K19/07749—Constructional details, e.g. mounting of circuits in the carrier the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B13/00—Burglar, theft or intruder alarms
    • G08B13/22—Electrical actuation
    • G08B13/24—Electrical actuation by interference with electromagnetic field distribution
    • G08B13/2402—Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting
    • G08B13/2405—Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting characterised by the tag technology used
    • G08B13/2408—Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting characterised by the tag technology used using ferromagnetic tags
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B13/00—Burglar, theft or intruder alarms
    • G08B13/22—Electrical actuation
    • G08B13/24—Electrical actuation by interference with electromagnetic field distribution
    • G08B13/2402—Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting
    • G08B13/2405—Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting characterised by the tag technology used
    • G08B13/2414—Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting characterised by the tag technology used using inductive tags
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B13/00—Burglar, theft or intruder alarms
    • G08B13/22—Electrical actuation
    • G08B13/24—Electrical actuation by interference with electromagnetic field distribution
    • G08B13/2402—Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting
    • G08B13/2428—Tag details
    • G08B13/2431—Tag circuit details
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B13/00—Burglar, theft or intruder alarms
    • G08B13/22—Electrical actuation
    • G08B13/24—Electrical actuation by interference with electromagnetic field distribution
    • G08B13/2402—Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting
    • G08B13/2428—Tag details
    • G08B13/2437—Tag layered structure, processes for making layered tags
    • G08B13/2442—Tag materials and material properties thereof, e.g. magnetic material details

Definitions

  • TITLE A METHOD AND DEVICE FOR IDENTIFICATION PURPOSE
  • the present invention relates to a device for identification of objects, for example goods to be sold or identified in an inventory system.
  • Such means of identification may be a tag attached to the goods, such as RFID tags.
  • Identification of articles is desired in many applications.
  • the goods to be sold may be marked with tags.
  • the tag may be read at passage out of the store for different purposes. Such purpose may be to charge payment for the goods and/or for inventory purpose.
  • An identification system is shown, for example, in document WO 00/75894, which discloses a tag for electronic article identification.
  • the tag has several magnetic elements, which represent an identify of the tag, or the identity of an article to which the tag is attached.
  • the magnetic elements may be electromagnetically detected and are formed of wires made from an amorphous or nano-crystalline magnetic metal alloy.
  • the magnetic elements are arranged at predetermined angles to each other. At least one of the magnetic elements has a length, which is different from the length of the other magnetic elements of the tag.
  • At least one of the magnetic elements has a diameter, which is different from the diameter of the other magnetic elements of the tag.
  • the lengths and diameters of the magnetic elements, and the angles between them, jointly form the identity of the tag.
  • the magnetic field may be modulated by a low frequency signal.
  • the permeability of the element will change with the low frequency signal. If the element is exposed to an electromagnetic detection signal, such as a microwave signal, the reflectance properties of the element change with the magnetic field and the reflected microwave signal will be amplitude modulated with the low frequency signal. In this way, the length, the diameter and the angular direction of the element can be determined.
  • Document WO 93/14478 discloses a method and a device for remote sensing of objects.
  • the object is provided with a label comprising an electrical resonant circuit.
  • the resonant circuit is excited to resonance at a resonance frequency.
  • the resonance frequency of the resonant circuit is determined based on the electromagnetic energy transmitted from said resonant circuit.
  • An element of a magnetic material having a varying permeability is coupled inductively to an induction element of the resonant circuit.
  • the resonant frequency of said resonant circuit is affected by the permeability of said element of magnetic material.
  • the element of magnetic material is exposed to an external and spatially
  • Document WO 99/66466 A2 discloses a method for remote detection of objects, each object being provided with a sensor comprising at least two magnetic elements arranged in a predetermined mutual relationship representing an identity of the sensor. Electromagnetic signals are generated for exciting the sensor elements to produce electromagnetic reply signals. An amplitude of the electromagnetic reply signal from each sensor element is modulated by a first magnetic field having a magnitude-variant and a magnitude-invariant component. A second magnetic field is generated with rotating field vector.
  • a frequency shift is detected in a component of said reply signal, when a magnitude-invariant component of said second magnetic field balances the magnitude-invariant component of said first magnetic field, wherein the respective sensor element is momentarily exposed to a resulting magnetic field with essentially no magnitude-invariant component.
  • An orientation of the respective sensor element is determined from the orientation of the magnitude-invariant component of said second magnetic field, when said frequency shift occurs.
  • All the above-mentioned systems require that the tag enters a magnetic field with certain properties.
  • the influence of the magnetic field on a magnetic element in the tag is monitored, for example by a microwave system.
  • the monitoring can take place at a long distance of several tenths of meters or even 100 meters, but the magnetic field cannot be generated at such a distance. If the system should be made operative at larger distances, large magnets are required.
  • the system comprises a transponder comprising a retroreflecting arrangement and a modulation arrangement.
  • the modulating arrangement is arranged to apply a predetermined typ of patter of modulation to incident microwave radiation passing therethrough and reflected back to the source by the retroreflecting arrangement.
  • the modulation is obtained by passing the radiation through a varying magnetic field.
  • this system requires that the transponder is arranged in a specific manner in relation to the microwave source.
  • the modulation obtained by the varying magnetic field is weak, making the system difficult to detect.
  • the tag may be active, i.e. comprise a power source on-board, or passive, i.e. operable without an on-board power source.
  • an object of the present invention is to mitigate, alleviate or eliminate one or more of the above-identified deficiencies and disadvantages singly or in any combination.
  • a device for identification of an object comprising a magnetic element attached to the object, said magnetic element having a permeability, which is dependent on a magnetic field exposed to the magnetic element; a source of an alternating magnetic field for exposure of said magnetic element; and a microwave transmitter for exposing said magnetic element for microwaves and a microwave receiver for receiving microwaves reflected and/or retransmitted from said magnetic element and modulated by said alternating magnetic field; characterized in that said source of an alternating magnetic field is arranged on-board of the object.
  • the source of an alternating magnetic field may comprise an LC-circuit having a resonance frequency and wherein said magnetic element may be arranged adjacent an symmetry axis of a L-member of said LC-circuit.
  • the source of an alternating magnetic field may comprise a source of an alternating voltage or current having the same frequency as said resonance frequency and being powered by an energy source.
  • the energy source may be a battery.
  • the energy source may be energy which has been wirelessly transmitted to the object, and being electromagnetic radiation, ultrasound, or induction.
  • the source of an alternating magnetic field may comprise an oscillator circuit, the output of which may be connected to the ends of the magnetic element in order to pass an electric alternating current through the magnetic element.
  • the oscillator circuit may be arranged to generate several discrete frequencies in a time sequence, which frequencies form an identity of the object.
  • the magnetic element may be an amorphous or nano-crystalline magnetic wire.
  • the length of the magnetic wire may be half the wavelength of the microwaves.
  • the said source of an alternating magnetic field may comprise an oscillator circuit, the output of which is connected to the ends of a wire arranged adjacent and extending in parallel with the magnetic element in order to pass an electric alternating current through the wire for generating said alternating magnetic field.
  • Fig. 1 is a schematic diagram of a first embodiment.
  • Fig. 2 is a schematic diagram of a second embodiment including a circuit diagram of an oscillator.
  • Fig. 3 is a schematic diagram of a third embodiment.
  • Fig. 4 is a schematic diagram of a fourth embodiment.
  • Fig. 5 is a schematic diagram of a fifth embodiment.
  • Fig. 6 is a circuit diagram of an oscillator intended to be used in the fifth
  • Such a magnetic element is made of an amorphous or nano-crystalline magnetic wire for example as disclosed in WO 97/24734A1, the contents of which is incorporated in the present specification by reference.
  • This material may exhibit Giant Magnetoresistive properties or even Colossal Magnetoresistive properties, which might explain why a small magnetic field may cause a large change of permeability.
  • permeability is defined as the degree of magnetization of a material that responds to an applied magnetic field. Magnetic permeability is typically represented by the Greek letter ⁇ . The permeability is measured in Henry per meter (H/m), or Newton per ampere squared (N/A A 2). The permeability of the magnetic material influences directly upon the reflectivity of the magnetic material when exposed to electromagnetic radiation, such as microwaves. Thus, a variation of the permeability of the material will cause an amplitude modulation of the microwaves, which are scattered, reflected and/or retransmitted from the magnetic material.
  • the magnetic wire acts as a receiving antenna, which receives the microwaves directed towards the magnetic wire.
  • the energy received by the antenna is immediately retransmitted in all directions.
  • a part of the received energy is retransmitted towards a receiver.
  • the magnetic wire is seen by a receiver as an element, which scatters the microwave radiation, and thus, the expression "scattering magnetic element" will be used below.
  • the element should be arranged as a wire, which may act as an "antenna".
  • the wire may be made of an electrically conducting material.
  • the antenna may have a length corresponding to half the wavelength of the microwave radiation.
  • the wire may have a permeability and/or resistivity, which is variable and may be modulated by a magnetic field. Without being bound by a theory, it is believed that the magnetic field influences upon both the permability and the resistivity of the wire, which causes a variable scattering.
  • Fig. 1 shows a first embodiment of the invention, which comprises a tag 11 provided with a scattering magnetic element 12, an inductor 13 and a capacitor 14.
  • the tag and the circuit are similar to the tag shown in WO 93/14478.
  • the first embodiment comprises in addition a source 15 of an alternating current or voltage.
  • the inductor 13 is a coil of wires forming a cylinder.
  • the magnetic element 12 may be arranged outside the cylinder in close relationship to the cylinder and with the magnetic element 12 extending parallel with an axis of the coil, as schematically shown in Fig. 1.
  • the magnetic element 12 may be arranged inside the cylinder adjacent or at the axis thereof, as
  • the voltage source 15 is arranged to produce an alternating voltage with a low frequency.
  • the resonance circuit 13 and 14 is tuned to said low frequency.
  • the inductor 13 generates an alternating magnetic field, which is parallel with the scattering magnetic element 12 and modulates the permeability of the scattering magnetic element with the low frequency.
  • a microwave transmitter 16 transmits microwaves towards the scattering magnetic element and receives microwaves scattered by the scattering magnetic element 12 by a microwave receiver 17.
  • the tag itself comprises an on-board circuit 13, 14, 15 for producing an alternating magnetic field at the magnetic element 12.
  • Another difference in relation to WO 93/14478 is that in the present embodiment, the magnetic element is monitored by a microwave transceiver 16, 17.
  • the microwave transmitter 16 and receiver 17 can be arranged at a distance of several tenths of meters, or even 100 meters from the tag and will still be able to detect the low frequency modulation of the scattered or reflected microwaves.
  • a power source 15 with low energy contents can be used in the tag, which makes the tag light and cheap.
  • an alternating voltage source 15 is shown.
  • Such voltage source may be driven by a small battery arranged at the tag.
  • the alternating voltage may be obtained by a conventional oscillator circuit, such as a Hartley oscillator, a Colpitts oscillator, an Armstrong oscillator etc.
  • Fig. 2 shows a second embodiment comprising a conventional Hartley oscillator comprising a FET transistor 18 and a battery 19.
  • a switch 28 is arranged in the battery circuit and normally prevents current from passing out of the battery 19.
  • the switch 28 comprises an insulating material 29 normally arranged between two contacts. When the insulating material 29 is removed, the switch is closed and the circuit starts to oscillate at a frequency determined by the inductor 13 and the capacitor 14. The circuit oscillates until the battery is out of energy or the switch is opened.
  • the material 29 may be removed, for example manually, when the goods is taken from the shelf. If the battery time is sufficient for 6 hours, there is ample time for the buyer to pass the cost charging system.
  • the insulating material 29 can be removed in many different ways.
  • the material may include a substance that absorbs energy when passing an induction field so that the material melts.
  • the material may be an optical material that conducts current when exposed to light. The material may be removed manually, etc.
  • the tag may be used for identification purpose.
  • the tag may indicate a number associated with the goods, for example as used in an EAN system.
  • the number may be arranged in a memory arranged at the tag.
  • An output of the memory may interact with the capacitor 14, which may be a variable capacitor, the capacitance of which is altered by an external voltage.
  • the capacitor 14 which may be a variable capacitor, the capacitance of which is altered by an external voltage.
  • the tag may alternatively or additionally be used for a theft protection system.
  • the oscillator may have a fixed frequency. When said fixed frequency is sensed by sensor in an outpassing device from the shop, an alarm may be triggered.
  • the magnetic element is arranged parallel with a symmetry axis of the inductive coil element, which may have the same or larger length compared to the magnetic element.
  • the magnetic field should be directed in parallel with the magnetic element in order to influence as efficiently as possible on the permeability of the magnetic element.
  • the modulating magnetic field may be produced by exposing the LC-circuit for an electromagnetic radiation from a radio wave transmitter 36.
  • the LC-circuit may be tuned to a frequency of 200 kHz and an electromagnetic radiation with this frequency is directed towards the LC- circuit 13, 14.
  • the radiation will cause a current in the LC-circuit.
  • the current will be amplified.
  • the current in the L-element, i.e. the coil will produce a magnetic field inside the coil, which is amplified in relation to the free (electro-) magnetic field of the radiation, because of the Q-value of the LC-circuit.
  • the amplified magnetic field influences upon the scattering magnetic element 12 inside the coil and changes the permeability of the magnetic material.
  • the magnetic material is in addition exposed to microwaves from the transmitter 16, which are modulated by the changes in the permeability.
  • the modulated microwaves can be detected at a large distance by the receiver 17.
  • the tag according to the second embodiment can be considered to be a semi-passive tag. Since there is no power source on-board, the tag will operate at any time.
  • the on-board voltage source may include a capacitor, which is charged from a distance and then forms a voltage source when needed.
  • Wakeup circuitry is known in the prior art for producing an oscillating signal when activated by an electromagnetic signal.
  • the operation according to the second embodiment is different from the operation described in the publication WO 93/14478. It was unexpected to find that electromagnetic radiation, having low frequency, could change the magnetic properties of the scattering magnetic element 15 to such a degree, that it was detectable at a large distance by
  • the low frequency may be a few kHz up to several MHz. see further below.
  • the scattering magnetic element 12 should have certain properties.
  • the magnetic material may be an amorphous or nano-crystalline magnetic wire for example as disclosed in WO 97/24734A1, the contents of which is incorporated in the present specification by reference.
  • This material may exhibit Giant Magnetoresistive properties or even Colossal Magnetoresistive properties, which might explain why such a small magnetic field may cause such a large change of permeability.
  • the material may be for example an amorphous magnetic wire comprising a metallic amorphous core with a diameter ranging between 5 and 25 ⁇ m and of a composition based on Co containing 20 atomic % or less Si, 7 up to 35 atomic % B and 25 atomic % or less of one or more metals selected from the group Fe, Ni, Cr, Ta, Nb, V, Cu, Al, Mo, Mn, W, Zr, Hf and a glass cover with the thickness ranging between 1 and 15 ⁇ m, for example an alloy of composition Co70Fe5B15SilO.
  • the wire may be thin, such as below 25 ⁇ m, and may have a length adapted to the microwave frequency, such as about 49 mm for a microwave frequency of 2.45 GHz, which corresponds to half the wavelength of the microwaves. In another embodiment, the length is selected to correspond to the full wavelength or any length between the full wavelength and half the wavelength.
  • the tag may be exposed to a low frequency electromagnetic field, which is picked up by the coil of the resonance circuit, whereby a current is generated and a magnetic field is formed inside the inductor.
  • the low frequency field may be an electromagnetic field, for example in the long-wave range at about 200 kHz.
  • the transmitter 36 for such a long- wave electromagnetic field can be arranged at any distance from the tag, which is mainly only determined by the power of the source of long-wave radiation.
  • the resonance circuit will amplify the long-wave energy and produce a magnetic field, which is sufficient for influencing upon the permeability of the wire and cause amplitude modulation of the microwaves.
  • the long-wave radiation source may send radio waves at different frequencies and detect possible magnetic elements by the modulation of magnetic properties of the magnetic element.
  • a tag having a frequency resonance at frequency 220 kHz and a tag having a frequency resonance at 625 kHz are present, there will be microwave modulation signals at these frequencies, and the corresponding goods may be identified.
  • the on-board voltage source may include a capacitor, which is charged from a distance and then forms a voltage source when needed.
  • Wakeup circuitry is known in the prior art for producing an oscillating signal when activated by an electromagnetic signal.
  • the magnetic field is parallel with the length direction of the wire, and an inductor 13 and a capacitor 14, tuned to a low frequency, are used for generating a low-frequency, alternating magnetic field.
  • an inductor 13 and a capacitor 14, tuned to a low frequency are used for generating a low-frequency, alternating magnetic field.
  • such components may become relatively cumbersome at low frequencies.
  • the inductor 13 and the capacitor 14 has been replaced by a single wire 23 extending in parallel with the scattering magnetic element 22.
  • the voltage source may for example be said piezo-electric ultrasound transducer 25 or a separate oscillator driven by an on-board battery, such as for example the circuit shown in Fig. 6.
  • the magnetic field influencing upon the magnetic element 22 will be perpendicular to the longitudinal direction of the magnetic element.
  • the magnetic field is circular around the conductor 23.
  • the circuit produced a pronounced change of permeability of the magnetic element 22. This effect cannot be readily explained, but it is believed that it has something to do with the Giant Magnetoresistive properties of the magnetic material in the magnetic element.
  • the single wire 23 may have a predetermined resistivity, which is adapted to the power source.
  • the single wire 23 is arranged as close as possible to the scattering magnetic element 22.
  • Fig. 5 shows a fifth embodiment, wherein the alternating voltage source 25 is connected directly to the scattering magnetic element 32 so that an alternating current passes through the magnetic element 32, which acts as a conductor.
  • the alternating current produces a circular magnetic field.
  • still better performance may be obtained compared to the forth embodiment shown in Fig. 4. Again, this surprising effect cannot be easily explained.
  • the embodiments according to the invention can be used in many applications.
  • the frequency of the voltage source 15 can be set to a predetermined value, which is an identification of the tag.
  • n is a number between 1 and 1000, which gives 1000 identities.
  • 10 ⁇ 6 different identities may be coded.
  • n is a number between 100 and 1100.
  • the circuit 35 may be arranged to produce a series of frequencies, which are repeated until the battery power has been consumed. These frequencies may form the identity of the tag.
  • the tag is triggered to start producing said series of frequencies by an external signal, for example as mentioned above in connection with Fig. 2.
  • the oscillator may be an astabile multivibrator having several capacitors connected one after the other in time sequence to produce several frequencies after each other. Such a circuit is shown in Fig. 6.
  • the circuit of Fig. 6 is built around a circuit 61, a so called 555-IC, which is well known.
  • the 555-IC produces a square wave output signal, with a frequency defined by a capacitor at the input thereof.
  • a first capacitor 62 is always connected to the circuit 61.
  • the circuit produces a square wave signal at an output 67, which has a high frequency, determined by the capacitor value.
  • a counter 68 is arranged to produce a binary signal at two output contacts connected to two switch members 65, 66, in the nature of MOSFET transistors, for adding capacitors 63 and 64 to the circuit 61.
  • the counter is arranged to produce the following sequence of signals:
  • both the switch members 65, 66 are switched off and only the first capacitor determines the frequency, which becomes high, for example 550 kHz.
  • the second capacitor 63 is connected in parallel with the first capacitor 62 and the frequency becomes lower, for example 320 kHz.
  • the third capacitor 64 is connected in parallel with the first capacitor 62 and the frequency becomes still lower, for example 260 kHz.
  • both the second capacitor 63 and the third capacitor 64 are connected in parallel with the first capacitor 62 and the frequency becomes still lower, for example 210 kHz.
  • the output signal is fed to the wire 32 of Fig. 5, or to the magnetic member of any of the embodiments. These four frequencies form an identity for the tag and the goods at which the tag is attached.
  • the frequencies are detected by the microwave transceiver 16, 17.
  • the stability of the circuit 61 is sufficient for defining for example 100 different frequencies, whereby the number of combination of four frequencies becomes 10 ⁇ 8. Further frequencies may be added for increased number of combinations, for example 6 or 10 frequencies.
  • the multivibrator circuit may be based on a crystal oscillator oscillating at a high frequency of for example 100 MHz and divided down by a counter to a range of 100 kHz to 1100 kHz. Such a multivibrator will be very stable.
  • 13, 14 may be square wave signals or sinusoidal signals or any other suitable wave-shape, such as triangular.
  • a battery may power the circuit 61 in the same manner as shown in Fig. 2.
  • the magnetic material will change its permeability at frequencies up to several MHz and down to zero Hz.
  • the circuit may comprise means for charging an on-board power source.
  • the power source When the power source has been charged, for example by ultrasound energy or induction or any other means, the circuit will be producing said series of frequencies.
  • the tag In this case, the tag is self-supporting and may operate at any time the energy is supplied.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Remote Sensing (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Automation & Control Theory (AREA)
  • Computer Security & Cryptography (AREA)
  • Electromagnetism (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Theoretical Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Computer Hardware Design (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geophysics (AREA)
  • Burglar Alarm Systems (AREA)
  • Geophysics And Detection Of Objects (AREA)

Abstract

La présente invention concerne un dispositif pour l’identification d’un objet, le dispositif comprenant un élément magnétique de diffusion (12, 22, 32) fixé à l’objet. L’élément magnétique de diffusion possède une perméabilité qui dépend du champ magnétique auquel est exposé l’élément magnétique. Le dispositif comprend en outre une source (13, 14; 15; 25; 35) de champ magnétique alternatif applicable au dit élément magnétique de diffusion. Un émetteur hyperfréquences (16) expose l’élément magnétique de diffusion à des ondes hyperfréquence et un récepteur hyperfréquence (17) reçoit des ondes hypefréquence diffusées ou réfléchies par l’élément magnétique de diffusion et modulées par le champ magnétique alternatif. La source de champ magnétique alternatif est incorporée à l’objet et est alimentée par une batterie. Dans un mode de réalisation, la source d’un champ magnétique alternatif comprend un circuit LC possédant une fréquence de résonance, l’élément magnétique de diffusion étant placé dans une position adjacente à un axe de symétrie d’un élément L du circuit LC. Dans un autre mode de réalisation, l’objet comprend un oscillateur dont la sortie est connectée aux extrémités de l’élément magnétique de diffusion pour le passage d’un courant alternatif à travers l’élément magnétique. L’élément magnétique de diffusion est fait d’un matériau magnétique tel qu’un câble magnétique amorphe ou nanocristallin dont la longueur correspond à la moitié de la longueur d’onde des ondes hyperfréquence.
PCT/SE2010/000203 2009-08-14 2010-08-14 Procédé et dispositif à des fins d’identification WO2011019311A1 (fr)

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EP10808422A EP2465103A1 (fr) 2009-08-14 2010-08-14 Procédé et dispositif à des fins d' identification

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SE0901082A SE534420C2 (sv) 2009-08-14 2009-08-14 En anordning för indentifieringsändamål
SE0901082-8 2009-08-14
US27621809P 2009-09-10 2009-09-10
US61/276,218 2009-09-10

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WO2011019311A1 true WO2011019311A1 (fr) 2011-02-17

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RU2529867C2 (ru) * 2013-01-10 2014-10-10 Федеральное государственное бюджетное учреждение "Арктический и антарктический научно-исследовательский институт" Способ управления движением судов

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5576693A (en) * 1992-01-20 1996-11-19 Rso Corporation N.V. Method and device for remote sensing of objects
US20080284568A1 (en) * 2005-07-28 2008-11-20 Bae Systems Plc Transponder

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5576693A (en) * 1992-01-20 1996-11-19 Rso Corporation N.V. Method and device for remote sensing of objects
US20080284568A1 (en) * 2005-07-28 2008-11-20 Bae Systems Plc Transponder

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EP2465103A1 (fr) 2012-06-20
SE0901082A1 (sv) 2011-02-15
SE534420C2 (sv) 2011-08-16

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