WO2009136837A1 - A passive transponder and an item with a passive transponder - Google Patents

A passive transponder and an item with a passive transponder Download PDF

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Publication number
WO2009136837A1
WO2009136837A1 PCT/SE2009/000227 SE2009000227W WO2009136837A1 WO 2009136837 A1 WO2009136837 A1 WO 2009136837A1 SE 2009000227 W SE2009000227 W SE 2009000227W WO 2009136837 A1 WO2009136837 A1 WO 2009136837A1
Authority
WO
WIPO (PCT)
Prior art keywords
passive transponder
fabric
item
antenna
passive
Prior art date
Application number
PCT/SE2009/000227
Other languages
French (fr)
Inventor
Magnus Granhed
Karl-Gösta FORSSÉN
Original Assignee
Recco Invest Ab
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 Recco Invest Ab filed Critical Recco Invest Ab
Priority to EP09742919.5A priority Critical patent/EP2362960B1/en
Publication of WO2009136837A1 publication Critical patent/WO2009136837A1/en

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Classifications

    • 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
    • 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
    • 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
    • G06K19/02—Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the selection of materials, e.g. to avoid wear during transport through the machine
    • G06K19/027—Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the selection of materials, e.g. to avoid wear during transport through the machine the material being suitable for use as a textile, e.g. woven-based RFID-like labels designed for attachment to laundry items
    • 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
    • G06K19/07758—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 arrangements for adhering the record carrier to further objects or living beings, functioning as an identification tag
    • 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
    • G06K19/07773—Antenna details
    • G06K19/07786—Antenna details the antenna being of the HF type, such as a dipole
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
    • G06K7/10—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
    • G06K7/10009—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves
    • G06K7/10118—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves the sensing being preceded by at least one preliminary step
    • G06K7/10128—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves the sensing being preceded by at least one preliminary step the step consisting of detection of the presence of one or more record carriers in the vicinity of the interrogation device

Definitions

  • the invention relates to a passive transponder adapted to be embedded in fabrics.
  • the present invention also relates to an item, for example an absorbent fabric for medical purposes, provided with at least one passive transponder adapted to be attached to, embedded in or integrated into the item.
  • Absorbent fabrics are normally used to stop internal bleeding for instance during surgery in hospitals, and there is a potential risk that the absorbent fabrics are left inside a patient's body after surgery is completed, which may cause the patient to be sick, or even die, from this mistake. Thus, there is a need to determine if the absorbent fabrics have been removed after surgery, and preferably before the wound is closed by stitches.
  • a way to determine if the absorbent fabrics have been removed is to keep track of how many pieces of absorbent fabric have been put into the patient, and then count how many that has been removed. This is very impractical and a solution that may verify that all have been removed is more desirable.
  • a solution to this problem is to use any type of transmitting antennas, such as disclosed in US2006/0161225, by Sormann et al. and US2005/0095197, by Tus ⁇ ynski et al., embedded in absorbent fabrics, since it is easy to detect any absorbent fabric unintentionally left inside a human body after surgery.
  • An article from “Threadless @ Virginia Tech” with the title “News and Notes for our Industrial partners” (December 12, 2006) disclose patch antennas that can be embroidered into fabric with a conductive thread.
  • An object with the present invention is to provide passive transponders that are smaller and more flexible than prior art passive transponders.
  • a passive transponder comprising an antenna having two electrically conductive parts, a diode connected between the electrically conductive parts, and a transmission line connected to the antenna and to the diode.
  • Each electrical conductive part of the antenna comprises at least one flexible, electrically conductive, thread.
  • a second object with the present invention is to provide an item having a surface, adapted to be secured to an article with an arbitrary shape, to which surface a passive transponder may be attached to, or embedded in.
  • the second object is achieved by an item provided with at least one passive transponder with deformable properties attached to, or embedded in, the surface.
  • An object with a preferred embodiment is to provide a fabric which may be detected by a detector when the fabric is immersed in an electrically conductive environment, such as a human body.
  • This object is achieved by a fabric provided with at least one passive transponder embedded in or integrated into the fabric.
  • An advantage with the present invention is that the passive transponder is not including a power source and thus not transmitting RF power until a detector activates the passive transponder by transmitting RF power of the correct frequency.
  • Another advantage with the present invention is that RF power of a harmonic second frequency will be detected by the detector only if a passive transponder is present in the area under investigation.
  • a further advantage with the present invention is that the item (or fabric) may be handled in any way (by folding, crumple up, etc.) without jeopardizing the function of the passive transponder due to the flexible design.
  • Fig. 1 shows a first embodiment of a passive transponder according to the present invention.
  • Fig. 2 shows a second embodiment of a passive transponder according to the present invention.
  • Fig. 3 shows a third embodiment of a passive transponder according to the present invention. 009/000227
  • Fig. 4 shows a first embodiment of an item according to the present invention with embedded passive transponders.
  • Fig. 5 shows a second embodiment of an item according to the present invention with integrated passive transponders.
  • Fig. 6 shows a third embodiment of an item according to the present invention with passive transponders attached to its surface.
  • Passive transponders preferably need to be adapted to a desired receiving frequency and a transmitting frequency, which normally is twice as high as the receiving frequency, but any harmonic frequency will be sufficient for the passive transponder to work properly.
  • the procedure to adapt the passive transponders has been described in US 6,456,228, and is hereby incorporated as reference.
  • FIG. 1 shows a first embodiment of a passive transponder 10 comprising a diode 11, an antenna having two electrically conductive parts 12a and 12b, and a transmission line 13.
  • Each electrically conductive part 12a, 12b of the antenna comprises in this embodiment an elongated thread 14 (or wire) having a first end 15 and a second end 16.
  • the diode 11 is electrically connected between the first ends 15 of the elongated threads 14, and the transmission line 13, preferably implemented as a flexible thread, is adapted to match the impedance of the diode 11 to an impedance of the antenna by arranging the transmission line between the two electrically conductive parts 12a and 12b of the antenna.
  • a dielectric cover 17 is preferably arranged to encompass the antenna, transmission line 13 and diode 11, as indicated by the dash-dotted line in the figure, to improve the performance of the passive transponder.
  • FIG. 2 shows a second embodiment of a passive transponder 20 comprising a diode 21, an antenna having two conductive parts 22a and 22b, and a transmission line 23.
  • Each electrically conductive part 22a, 22b, of the antenna comprises in this embodiment a short thread 24 having a first end 25 and a second end 26, and a thin narrow foil strip 28 electrically connected to the second ends 26 of the threads 24.
  • the diode 21 is electrically connected between the first ends 25 of the threads 24, and the transmission line 23, preferably implemented as a flexible thread, is adapted to match the impedance of the diode 21 to an impedance of the antenna by arranging the transmission line 23 between the two electrically conductive parts 22a and 22b of the antenna.
  • a dielectric cover 27 is preferably arranged to encompass the antenna, transmission line 23 and diode 21, as indicated by the dash-dotted line in the figure, to improve the performance of the passive transponder.
  • FIG. 3 shows a third embodiment of a passive transponder 30 comprising a diode 31 , an antenna having two conductive parts 32a and 32b, and a transmission line 33.
  • Each electrically conductive part 32a, 32b, of the antenna comprises in this embodiment an elongated thread 34 having a first end 35 and a second end 36; and at least one additional thread, in this embodiment four additional threads 38, electrically connected to a point 39 on the elongated thread 34 situated between the first end 35 and the second end 36 of each thread 34.
  • the diode 31 is electrically connected between the first ends 35 of the threads 34, and the transmission line 33, preferably implemented as a flexible thread, is adapted to match the impedance of the diode 31 to an impedance of the antenna by arranging the transmission line 33 between the two electrically conductive parts 32a and 32b of the antenna.
  • a dielectric cover (not shown) may be arranged to encompass the antenna, transmission line 33 and diode 31, as discussed in connection with figure 5.
  • a passive transponder may be as small as 1 x 10 mm, but is preferably 2 x 30 mm, and enclosed in a dielectric material with a high dielectric constant, such as silicone.
  • the essential property of the passive transponder is that a piece of conducting material is attached to each side of a diode, and a transmission line is arranged between each side of the diode.
  • the electrically conductive material of the antenna and the transmission line of the passive transponders is preferably a highly flexible material which may be folded without damaging the electrical properties of the material, e.g. insulated metal wires, or conductive threads as illustrated in connection with figure 5. It is naturally possible to replace the diode with any type of semiconductor component that has a PN junction, which is obvious for a skilled person in the art.
  • the dielectric material used to form the dielectric cover is present to reduce the influence of the surroundings of the passive transponder in a near field of the antenna.
  • FIG 4 shows a first embodiment of a fabric 40 having at least one passive transponder, in this embodiment two passive transponders 41 and 42 are illustrated being perpendicularly arranged to each other, embedded therein.
  • Any of the passive transponders described in connection with figures 1-3 may be arranged at the edge 43, e.g. embedded in a hem or an edge seam 44, of the fabric 40.
  • the passive transponders are preferably enclosed in a dielectric material, which also is a biocompatible material in order to prevent any unwanted materials in the passive transponder to come in contact with fluids and human organs when the fabric is placed within a human body.
  • the fabric is preferably absorbent, and is used to absorb human body fluids, e.g. blood, during surgery.
  • FIG. 5 shows a second embodiment of a woven, or non-woven, fabric 50 having one passive transponder 51 integrated in the fabric by using conductive threads 52 as antenna and transmission line, which are illustrated by the dashed lines, electrically connected to each other and to a diode 53.
  • a dielectric biocompatible, preferably flexible, material, such as silicone.
  • the biocompatible material is preferably arranged over the passive transponder 51 by applying a liquid gel. The gel will harden when exposed to air and form a cover, i.e. the passive transponder is coated with a flexible biocompatible material 54 that will prevent contact with the conductive components of the passive transponder.
  • the fabric 50 may be formed into an arbitrary shape adapted for a product, e.g. a compress for absorbing fluids or a tamponade for flow stoppage of blood, used during medical treatment or surgery.
  • a product e.g. a compress for absorbing fluids or a tamponade for flow stoppage of blood, used during medical treatment or surgery.
  • radio frequency (RF) power of a first frequency fi needs to be transmitted from a detector.
  • the retransmitted RF power of the harmonic frequency fh preferably the second harmonic frequency ⁇ 2, is detected by the detector and the presence of the passive transponder is verified. If no RF power of the harmonic frequency is detected, there are no passive transponders present, and thus no fabric.
  • a detector which is commercially available from Recco AB, is preferably swept over an object, such as a living body of a patient, at a close distance to detect the presence of any passive transponder.
  • the sweeping procedure is preferably performed prior to completion of the surgical operation, but it is also possible to verify the non-presence of passive transponders after the patient has left the operating room.
  • FIGS. 4 and 5 illustrate the use of the inventive passive transponder embedded in, or integrated in, a fabric, the invention should not be limited to this.
  • Figure 6 show an item 60 having flexible properties, such as an adhesive label, or a sheet of material, e.g. plastic, that may be provided with a passive transponder 61 as described in connection with figures 1-3.
  • the passive transponders may be provided with an adhesive layer to facilitate adhesion to a non-adhesive surface of an item.
  • Item 60 is preferably a label (as illustrated in figure 6) provided with a passive transponder that may be attached to a larger article, such as a container with hazardous material.
  • the surface of the article may have an arbitrary shape.
  • the article may be detected by a detector and its location verified in order to prevent articles to be stored, or placed, in e.g. a non- permitted area.

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Abstract

The present invention relates to a passive transponder comprising: an antenna having two electrically conductive parts; a diode connected to the antenna; and a transmission line connected to the antenna and to the diode. The transmission line is adapted to match the impedance of the diode to an impedance of the antenna, wherein the passive transponder, when hit by RF power of a first frequency f1, retransmits RF power of a harmonic frequency fh. Each electrically conductive part of the antenna comprises a flexible conductive thread having a first end and a second end, wherein the diode is connected to a first end of the flexible conductive threads. The invention also relates to an item, such as a fabric or adhesive label, including at least one passive transponder.

Description

A PASSIVE TRANSPONDER AND AN ITEM WITH A PASSIVE TRANSPONDER
Technical field
The invention relates to a passive transponder adapted to be embedded in fabrics. The present invention also relates to an item, for example an absorbent fabric for medical purposes, provided with at least one passive transponder adapted to be attached to, embedded in or integrated into the item.
Background to the invention
Absorbent fabrics are normally used to stop internal bleeding for instance during surgery in hospitals, and there is a potential risk that the absorbent fabrics are left inside a patient's body after surgery is completed, which may cause the patient to be sick, or even die, from this mistake. Thus, there is a need to determine if the absorbent fabrics have been removed after surgery, and preferably before the wound is closed by stitches.
A way to determine if the absorbent fabrics have been removed is to keep track of how many pieces of absorbent fabric have been put into the patient, and then count how many that has been removed. This is very impractical and a solution that may verify that all have been removed is more desirable.
A solution to this problem is to use any type of transmitting antennas, such as disclosed in US2006/0161225, by Sormann et al. and US2005/0095197, by Tus∑ynski et al., embedded in absorbent fabrics, since it is easy to detect any absorbent fabric unintentionally left inside a human body after surgery. An article from "Threadless @ Virginia Tech" with the title "News and Notes for our Industrial partners" (December 12, 2006) disclose patch antennas that can be embroidered into fabric with a conductive thread.
However, it is not desirable to embed transmitting antennas into an absorbent fabric intended to be used during surgical procedures. A passive component that does not emit any signals until the detection takes place is desirable.
Passive transponders that, when hit by a RF power of a first frequency fi, retransmit RF power of a second harmonic frequency £2, are known from US 6,456,228. However, these are large in size and less flexible than is needed in order to be able to attach them to an arbitrarily shaped surface or embed them into a fabric.
Therefore, there is a need to provide a new type of passive transponders.
Summary of the invention
An object with the present invention is to provide passive transponders that are smaller and more flexible than prior art passive transponders.
The object is achieved by a passive transponder comprising an antenna having two electrically conductive parts, a diode connected between the electrically conductive parts, and a transmission line connected to the antenna and to the diode. The transmission line is adapted to match the impedance of the diode to an impedance of the antenna, wherein the passive transponder, when hit by RF power of a first frequency fi, retransmits RF power of a harmonic frequency n-fi, (n=2,3,4,...). Each electrical conductive part of the antenna comprises at least one flexible, electrically conductive, thread.
A second object with the present invention is to provide an item having a surface, adapted to be secured to an article with an arbitrary shape, to which surface a passive transponder may be attached to, or embedded in.
The second object is achieved by an item provided with at least one passive transponder with deformable properties attached to, or embedded in, the surface. An object with a preferred embodiment is to provide a fabric which may be detected by a detector when the fabric is immersed in an electrically conductive environment, such as a human body.
This object is achieved by a fabric provided with at least one passive transponder embedded in or integrated into the fabric.
An advantage with the present invention is that the passive transponder is not including a power source and thus not transmitting RF power until a detector activates the passive transponder by transmitting RF power of the correct frequency.
Another advantage with the present invention is that RF power of a harmonic second frequency will be detected by the detector only if a passive transponder is present in the area under investigation.
A further advantage with the present invention is that the item (or fabric) may be handled in any way (by folding, crumple up, etc.) without jeopardizing the function of the passive transponder due to the flexible design.
Further objects and advantages will be apparent for a skilled person from the detailed description and the drawings.
Brief description of the drawings
Fig. 1 shows a first embodiment of a passive transponder according to the present invention.
Fig. 2 shows a second embodiment of a passive transponder according to the present invention.
Fig. 3 shows a third embodiment of a passive transponder according to the present invention. 009/000227
Fig. 4 shows a first embodiment of an item according to the present invention with embedded passive transponders.
Fig. 5 shows a second embodiment of an item according to the present invention with integrated passive transponders.
Fig. 6 shows a third embodiment of an item according to the present invention with passive transponders attached to its surface.
Detailed description of the preferred embodiments
Passive transponders preferably need to be adapted to a desired receiving frequency and a transmitting frequency, which normally is twice as high as the receiving frequency, but any harmonic frequency will be sufficient for the passive transponder to work properly. The procedure to adapt the passive transponders has been described in US 6,456,228, and is hereby incorporated as reference.
Figure 1 shows a first embodiment of a passive transponder 10 comprising a diode 11, an antenna having two electrically conductive parts 12a and 12b, and a transmission line 13. Each electrically conductive part 12a, 12b of the antenna comprises in this embodiment an elongated thread 14 (or wire) having a first end 15 and a second end 16. The diode 11 is electrically connected between the first ends 15 of the elongated threads 14, and the transmission line 13, preferably implemented as a flexible thread, is adapted to match the impedance of the diode 11 to an impedance of the antenna by arranging the transmission line between the two electrically conductive parts 12a and 12b of the antenna. A dielectric cover 17 is preferably arranged to encompass the antenna, transmission line 13 and diode 11, as indicated by the dash-dotted line in the figure, to improve the performance of the passive transponder.
Figure 2 shows a second embodiment of a passive transponder 20 comprising a diode 21, an antenna having two conductive parts 22a and 22b, and a transmission line 23. Each electrically conductive part 22a, 22b, of the antenna comprises in this embodiment a short thread 24 having a first end 25 and a second end 26, and a thin narrow foil strip 28 electrically connected to the second ends 26 of the threads 24. The diode 21 is electrically connected between the first ends 25 of the threads 24, and the transmission line 23, preferably implemented as a flexible thread, is adapted to match the impedance of the diode 21 to an impedance of the antenna by arranging the transmission line 23 between the two electrically conductive parts 22a and 22b of the antenna. A dielectric cover 27 is preferably arranged to encompass the antenna, transmission line 23 and diode 21, as indicated by the dash-dotted line in the figure, to improve the performance of the passive transponder.
Figure 3 shows a third embodiment of a passive transponder 30 comprising a diode 31 , an antenna having two conductive parts 32a and 32b, and a transmission line 33. Each electrically conductive part 32a, 32b, of the antenna comprises in this embodiment an elongated thread 34 having a first end 35 and a second end 36; and at least one additional thread, in this embodiment four additional threads 38, electrically connected to a point 39 on the elongated thread 34 situated between the first end 35 and the second end 36 of each thread 34. The diode 31 is electrically connected between the first ends 35 of the threads 34, and the transmission line 33, preferably implemented as a flexible thread, is adapted to match the impedance of the diode 31 to an impedance of the antenna by arranging the transmission line 33 between the two electrically conductive parts 32a and 32b of the antenna. A dielectric cover (not shown) may be arranged to encompass the antenna, transmission line 33 and diode 31, as discussed in connection with figure 5.
A passive transponder may be as small as 1 x 10 mm, but is preferably 2 x 30 mm, and enclosed in a dielectric material with a high dielectric constant, such as silicone. The essential property of the passive transponder is that a piece of conducting material is attached to each side of a diode, and a transmission line is arranged between each side of the diode. The process of E2009/000227
adapting the passive transponder to react to RF power of a desired frequency and to retransmit RF power of a harmonic frequency is readily apparent for a skilled person from the detailed description of US 6,456,228.
The electrically conductive material of the antenna and the transmission line of the passive transponders is preferably a highly flexible material which may be folded without damaging the electrical properties of the material, e.g. insulated metal wires, or conductive threads as illustrated in connection with figure 5. It is naturally possible to replace the diode with any type of semiconductor component that has a PN junction, which is obvious for a skilled person in the art.
Furthermore, the dielectric material used to form the dielectric cover, as illustrated in figures 1 and 2, is present to reduce the influence of the surroundings of the passive transponder in a near field of the antenna.
Figure 4 shows a first embodiment of a fabric 40 having at least one passive transponder, in this embodiment two passive transponders 41 and 42 are illustrated being perpendicularly arranged to each other, embedded therein. Any of the passive transponders described in connection with figures 1-3 may be arranged at the edge 43, e.g. embedded in a hem or an edge seam 44, of the fabric 40. The passive transponders are preferably enclosed in a dielectric material, which also is a biocompatible material in order to prevent any unwanted materials in the passive transponder to come in contact with fluids and human organs when the fabric is placed within a human body. Furthermore, the fabric is preferably absorbent, and is used to absorb human body fluids, e.g. blood, during surgery.
Figure 5 shows a second embodiment of a woven, or non-woven, fabric 50 having one passive transponder 51 integrated in the fabric by using conductive threads 52 as antenna and transmission line, which are illustrated by the dashed lines, electrically connected to each other and to a diode 53. When the fabric is intended for use inside a living body of a humar or animal, it is desirable to enclose the passive transponder with a dielectric. biocompatible, preferably flexible, material, such as silicone. Other suitable biocompatible materials are obvious for a skilled person in the art. The biocompatible material is preferably arranged over the passive transponder 51 by applying a liquid gel. The gel will harden when exposed to air and form a cover, i.e. the passive transponder is coated with a flexible biocompatible material 54 that will prevent contact with the conductive components of the passive transponder.
It is of course possible to fasten a pre-manufactured passive transponder, such as illustrated in any of figures 1-3, directly onto the fabric 50.
The fabric 50 may be formed into an arbitrary shape adapted for a product, e.g. a compress for absorbing fluids or a tamponade for flow stoppage of blood, used during medical treatment or surgery.
In order to be able to detect a piece of fabric, provided a passive transponder is attached to the fabric, radio frequency (RF) power of a first frequency fi needs to be transmitted from a detector. The transponder will then retransmit RF power of a harmonic frequency fh, i.e. a multiple of the first frequency fi, wherein
Figure imgf000008_0001
(n=2, 3, 4,...). The retransmitted RF power of the harmonic frequency fh, preferably the second harmonic frequency Ϊ2, is detected by the detector and the presence of the passive transponder is verified. If no RF power of the harmonic frequency is detected, there are no passive transponders present, and thus no fabric.
A detector, which is commercially available from Recco AB, is preferably swept over an object, such as a living body of a patient, at a close distance to detect the presence of any passive transponder. The sweeping procedure is preferably performed prior to completion of the surgical operation, but it is also possible to verify the non-presence of passive transponders after the patient has left the operating room. 009/000227
Although figures 4 and 5 illustrate the use of the inventive passive transponder embedded in, or integrated in, a fabric, the invention should not be limited to this.
Figure 6 show an item 60 having flexible properties, such as an adhesive label, or a sheet of material, e.g. plastic, that may be provided with a passive transponder 61 as described in connection with figures 1-3. The passive transponders may be provided with an adhesive layer to facilitate adhesion to a non-adhesive surface of an item.
Item 60 is preferably a label (as illustrated in figure 6) provided with a passive transponder that may be attached to a larger article, such as a container with hazardous material. The surface of the article may have an arbitrary shape. The article may be detected by a detector and its location verified in order to prevent articles to be stored, or placed, in e.g. a non- permitted area.

Claims

T/SE2009/000227Claims
1. A passive transponder (10; 20; 30; 41, 42; 51) comprising: an antenna having two electrically conductive parts (12a, 12b; 22a, 22b; 32a, 32b); a diode (11; 21; 31; 53) connected to the antenna; and a transmission line (13; 23; 33) connected to the antenna and to the diode, said transmission line is adapted to match the impedance of the diode to an impedance of the antenna, wherein the passive transponder, when hit by RF power of a first frequency fi, retransmits RF power of a harmonic frequency fh, c ha r a c t e r iz e d i n that each electrically conductive part (12a, 12b; 22a, 22b; 32a, 32b) of the antenna comprises a flexible conductive thread (14; 24; 34) having a first end (15; 25; 35) and a second end (16; 26; 36), wherein the diode (11; 21; 31; 53) is electrically connected to a first end (15; 25; 35) of the flexible conductive thread.
2. The passive transponder according to claim 1, wherein each electrically conductive part (22a, 22b) further is provided with at least one thin flexible narrow foil strip (28) electrically connected to the second end (26) of the flexible conductive thread (24).
3. The passive transponder according to claim 1, wherein each electrically conductive part (32a, 32b) further is provided with at least one additional flexible conductive thread (38) electrically connected to a point (39) on the flexible conductive thread (34) situated between the first end (35) and the second end (36) of the flexible conductive thread (34).
4. The passive transponder according to any of claims 1-3, wherein said flexible conductive threads are insulated metal wires.
5. The passive transponder according to any of claims 1-3, wherein said flexible conductive threads (52) are configured to be integrated into a fabric (50). 009/000227
10
6. The passive transponder according to claim 5, wherein said transmission line is a conductive thread configured to be integrated into the fabric (50).
7. The passive transponder according to any of claims 1-6, wherein the harmonic frequency fh is twice as high as the first frequency fi.
8. The passive transponder according to any of claims 1-7, wherein the passive transponder (10; 20; 41, 42) is enclosed in dielectric material in order to reduce influence of the surroundings of the passive transponder in a near field of the antenna.
9. The passive transponder according to claim 8, wherein said dielectric material is a biocompatible material.
10. The passive transponder according to any of claims 1-8, wherein said passive transponder is provided with an adhesive layer.
11. An item (40; 50; 60) including at least one passive transponder (41, 42; 51; 61) according to any of claims 1-10.
12. The item according to claim 11, wherein said item (60) is a flexible sheet of material, said at least one passive transponder (61) is attached to a surface of said flexible sheet of material.
13. The item according to claim 11 or 12, wherein said item is an adhesive label.
14. The item according to claim 11, wherein said item (40; 50) is a fabric.
15. The item according to claim 14, wherein said fabric is absorbent and adapted to be used for absorbing fluids.
16. The item according to any of claims 14 or 15, wherein said at least one passive transponder (41, 42) is embedded in the fabric. 009/000227
11
17. The item according to claim 16, wherein each passive transponder (41 , 42) is arranged at the edge (43) of the fabric, preferably enclosed by a hem, or edge seam (44) .
18. The item according to any of claims 14 or 15, wherein said at least one passive transponder (51) is integrated in the fabric.
19. The item according to claim 18, wherein the transmission line and the antenna of each passive transponder comprise conductive threads (52) arranged within the fabric.
20. The item according to any of claims 14-19, wherein said passive transponder is coated with a flexible biocompatible material (54) .
21. The item according to any of claims 14-20, wherein said fabric is formed into an arbitrary shape.
22. The item according to claim 21, wherein said fabric is formed into the shape of a compress or a tamponade.
PCT/SE2009/000227 2008-05-05 2009-05-05 A passive transponder and an item with a passive transponder WO2009136837A1 (en)

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US5033908P 2008-05-05 2008-05-05
SE0800991-2 2008-05-05
SE0800991A SE0800991L (en) 2008-05-05 2008-05-05 A passive transponder and an article with a passive transponder
US61/050,339 2008-05-05

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Cited By (3)

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WO2014131691A1 (en) * 2013-02-26 2014-09-04 Friedr. Dick Gmbh & Co. Kg Piercing- and/or cutting-resistant clothing article having a radio identification means on a flexible metal piece
US9118096B2 (en) 2010-06-30 2015-08-25 Bae Systems Plc Wearable antenna having a microstrip feed line disposed on a flexible fabric and including periodic apertures in a ground plane
WO2021089939A1 (en) 2019-11-08 2021-05-14 Primo1D Textile part provided with an electronic tag comprising a wired electronic device and method for producing such a part

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SE1130067A1 (en) 2011-07-08 2013-01-09 Comtrack Ab transponder System
KR102363632B1 (en) * 2014-12-29 2022-02-16 삼성전자주식회사 Method and apparatus for generating distress signal
EP3923195B1 (en) * 2020-06-11 2023-08-23 Primo1D Electronic label with a flexible and deformable nature

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WO2000048019A1 (en) * 1999-02-09 2000-08-17 Magnus Granhed Encapsulated antenna in passive transponders
WO2005067042A1 (en) * 2004-01-12 2005-07-21 Infineon Technologies Ag Method for electrically connecting an electrical conductor to an electronic component, and device
WO2008024921A2 (en) * 2006-08-23 2008-02-28 Jane Shen-Gunther Surgical sponge incorporating rfid technology and method of use

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US5465099A (en) * 1991-09-25 1995-11-07 Nippon Information Industry Corporation Detectable device and movable item detecting system
WO2000048019A1 (en) * 1999-02-09 2000-08-17 Magnus Granhed Encapsulated antenna in passive transponders
WO2005067042A1 (en) * 2004-01-12 2005-07-21 Infineon Technologies Ag Method for electrically connecting an electrical conductor to an electronic component, and device
WO2008024921A2 (en) * 2006-08-23 2008-02-28 Jane Shen-Gunther Surgical sponge incorporating rfid technology and method of use

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9118096B2 (en) 2010-06-30 2015-08-25 Bae Systems Plc Wearable antenna having a microstrip feed line disposed on a flexible fabric and including periodic apertures in a ground plane
WO2014131691A1 (en) * 2013-02-26 2014-09-04 Friedr. Dick Gmbh & Co. Kg Piercing- and/or cutting-resistant clothing article having a radio identification means on a flexible metal piece
WO2021089939A1 (en) 2019-11-08 2021-05-14 Primo1D Textile part provided with an electronic tag comprising a wired electronic device and method for producing such a part
EP4336406A2 (en) 2019-11-08 2024-03-13 Primo1D Textile part provided with an electronic tag comprising a wire-based electronic device, method for manufacturing such a part

Also Published As

Publication number Publication date
SE532089C2 (en) 2009-10-20
EP2362960B1 (en) 2014-03-12
EP2362960A1 (en) 2011-09-07
SE0800991L (en) 2009-10-20

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