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WO2007030003A1 - Antenne modulaire et système et procédé de détection d'objets - Google Patents

Antenne modulaire et système et procédé de détection d'objets Download PDF

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Publication number
WO2007030003A1
WO2007030003A1 PCT/NL2005/000652 NL2005000652W WO2007030003A1 WO 2007030003 A1 WO2007030003 A1 WO 2007030003A1 NL 2005000652 W NL2005000652 W NL 2005000652W WO 2007030003 A1 WO2007030003 A1 WO 2007030003A1
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WO
WIPO (PCT)
Prior art keywords
current
units
antenna
loops
magnetic field
Prior art date
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Ceased
Application number
PCT/NL2005/000652
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English (en)
Inventor
Rob Maaskant
Andries De Vries
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Stichting ASTRON
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Stichting ASTRON
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Filing date
Publication date
Application filed by Stichting ASTRON filed Critical Stichting ASTRON
Priority to PCT/NL2005/000652 priority Critical patent/WO2007030003A1/fr
Publication of WO2007030003A1 publication Critical patent/WO2007030003A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; 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
    • G06K7/10316—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 using at least one antenna particularly designed for interrogating the wireless record carriers
    • G06K7/10336—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 using at least one antenna particularly designed for interrogating the wireless record carriers the antenna being of the near field type, inductive coil
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q7/00—Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop

Definitions

  • the invention relates to an antenna for use in a system for detecting objects, such as radio frequency identification (RFID) tags or transponders, in an area monitored by the system.
  • the invention further relates to a system using such an antenna, to a monitored area including such a system, to a method for manufacturing said antenna, and to a method for detecting objects.
  • RFID radio frequency identification
  • Systems for detecting objects are known in the art, and are used for example in anti-theft systems in shops, in tracking and accounting of livestock, for the registration of rental cars at a parking lot, for the detection of ski-lift passes, for time registration with sport events or otherwise.
  • These known systems generate an energy field in an area monitored by the system, and are able to detect a transponder passing through the energy field.
  • the energy field is a magnetic or electromagnetic field, generated by an antenna.
  • Transponders may be either of an active or a passive type.
  • a passive transponder merely absorbs energy from the energy field generated by the detection system. This absorption may be detected, since it affects the energy field.
  • An active transponder absorbs energy from an energy field and uses the absorbed energy to transmit a signal. Examples of active transponders are RFID tags. In many circumstances, it is necessary to record data about a particular object, e.g. article in a shop, an animal or otherwise, and to distinguish between objects, e.g. which type of article.
  • an RFID tag absorbs energy from an electric, magnetic or electromagnetic field and uses the absorbed energy to transmit a radio frequency signal, which contains identification or other data recorded on the RFID tag.
  • an antenna for generating an electromagnetic field is known.
  • the antenna includes a support on which several planar inductive cells are provided.
  • the inductive cells are connected in parallel, such that the fields generated by the cells are superimposed and enhance each other.
  • a disadvantage of the known systems is that they cannot be used in different applications. For example, when the known antenna is to be used initially in the detection of transponders in car tyres, and thereafter is to be used as an anti-theft system in shops, or when the antenna is used to monitor differently dimensioned spaces, this would not be possible without modifying the entire antenna.
  • properties of the monitored area or the transponder are adjusted to fit the antenna. For example, the sizes of a passage may be restricted to an antenna size or the speed of a tag passing through the monitored area might be limited to the time required to detect the presence of the tag in the monitored area.
  • an antenna according to claim 1 is provided.
  • Such an antenna can be used in a large variety of applications since it has a modular construction.
  • the antenna can be composed out of an arbitrary number of units, depending on, for example, the specific area to be monitored, the expected tag movement, or other circumstances. Furthermore, because the current paths of at least two of said units are connected electrically or magnetically to each other such that they behave like a single magnetic source, the field generated can be improved, and e.g. unwanted destructive interference be prevented.
  • Fig. 1 shows schematically an example of an embodiment of a system according to the invention.
  • Fig. 2 shows a perspective view of an example of a unit suitable for the generator in the example of fig. 1.
  • Fig. 3 shows a tilted, perspective view of a side of the example of fig. 2.
  • Fig. 4 shows an example of an arrangement of two units connected with coupling elements to each other.
  • Fig. 5 shows an example of a coupling element.
  • Fig. 6 shows an example of a magnetic field generator suitable for the system of fig. 1.
  • Fig. 7 shows another example of a magnetic field generator suitable for the system of fig. 1.
  • Fig. 1 schematically shows an example of an embodiment of a detection system 1 according to the present invention.
  • the detection system 1 is arranged to monitor an area 2, and to detect objects in the monitored area 2.
  • the monitored area 2 is confined at the bottom 21 and at upright sides 22,23.
  • the ground forms a boundary of the monitored area.
  • a magnetic field generator 3 and the detector 4 form respective boundaries of the monitored area 2.
  • the monitored area 2 is open at a top 20 and passage sides 24,25. Objects may enter and/or leave the monitored area 2 at the, open, passage sides 24,25 in a direction of passage P through the monitored area 2 or in a direction opposite to the direction of passage P. From hereon, the passage side at the left in fig.
  • a system 1 with a passage-like monitored area 2 is especially suited for detecting the presence of objects which enter and/or leave a confined space, e.g. a shop.
  • the system 1 may be positioned at an entrance or exit of the confined space, e.g. the door of a shop, and for example be positioned such that the monitored area 2 lies with its entrance side 24 or its exit side 25 adjacent to the entrance or exit of the confined space.
  • the invention is not limited to such applications, and the system 1 may also be present in an open area, and be used to detect the presence as well as the position of objects in the monitored area 2.
  • the system may be implemented such that the magnetic field generator generates a magnetic field H in the entire space, e.g. a storage room or a plant.
  • the monitored area 2 is open at one or more sides, for example by using a magnetic field generator 3, and optionally a detector 4, placed at a central position in the monitored area 2.
  • the system 1 shown in fig. 1 further includes a magnetic field generator 3 and a detector 4.
  • the magnetic field generator 3 may also be referred to as an antenna, .
  • the generator 3 and the detector 4 are connected to a control device 5 via suitable connections 50-55.
  • the magnetic field generator 3 is able to generate a magnetic field H in the monitored area 2.
  • the control device 5 can control the magnetic field generator, and send suitable control signals via the connections 50- 54.
  • the detector 4 may detect a signal transmitted by a transponder 6 in response to an absorption of energy from the magnetic field H by the transponder 6. In response to the detection, the detector 4 transmits a detection signal to the control device 5 via the connection 55.
  • the control device 5 processes the detection signal further, and e.g. outputs a warning signal in a for humans perceptible form.
  • a transponder 6 is of a passive type, its presence in the monitored area 2 may be detected by the detector 4, since a transponder 6 passing through the magnetic field H absorbs energy from the field. This absorption is monitored as an increment of the power that needs to be fed to the field generator. A passive transponder 6 thus passively transmits a signal in response to the magnetic field H.
  • the amount of absorption may be constant of vary in time for example because of a movement of the transponder through the energy field.
  • a transponder 6 is of an active type, e.g. an RFID tag
  • its presence in the monitored area may be detected, since the transponder 6 will actively transmit an (electro) magnetic signal in response to an absorption of energy from the magnetic field H by the transponder 6.
  • an active transponder uses the absorbed energy to drive an electronic circuit which outputs the signal.
  • the signal will be an electromagnetic signal with a radio frequency.
  • any suitable type of detector may be used. Detectors for passive and/or active transponders are generally known in the art and for the sake of brevity not described in further detail.
  • the shown example of a field generator 3 includes a plurality of modular units 31, which may for instance be implemented as shown in figs. 2,3 and 4.
  • Each of the units 31 includes a base, or physical carrier, and may be provided with at least one current path.
  • the base may for example be made of a dielectric material.
  • the material is magnetically or electromagnetically transparent, in which case the energy field is not influenced by the base.
  • the units 31 are substantially similar. Thereby, the units 31 may be manufactured in the same manufacturing process. However, the units 31 may also be different.
  • the generator 3 may include two or more types of unit 31, for example a type with a rectangular shaped base with a length different from the width and a type with a square base.
  • more or less units 31 may be present than shown in fig. 1 and/or the units 31 may be provided in a different arrangement.
  • a generator 3 composed out of the unit 31 can be adapted.
  • the units 31 can be combined to form a field generator 3 of which the electromagnetic field is customised to a specific area to be monitored, e.g. preventing a tag 6 from passing around, over or underneath the (electro)magnetic field H generated by the generator 3.
  • a generator 3 may be obtained which is specifically suited to detect an object in a specific application.
  • the field generator 3 can be made to generate an energy field extending over a distance in the direction of passage Psuch that the tag 6 is present in the energy field during at least a period of time it takes the system to detect the presence of the tag, by providing an arrangement of units 31 which is, in the direction of passage, relatively long whereas in case the tags have a relatively low speed, the generator 3 may be adapted, in the direction P of passage, by reducing the number of units 31 in the direction P of passage.
  • the field generator 3 can also easily be adjusted to a new or changing situation.
  • elements 31 used in an anti theft system may be configured in an upright, five-by-five matrix as shown in fi.g.1.
  • the same units 31 can later for example be used as part of a four-by- thirty matrix of a horizontal field generator used in a time registration system at the finish line of a marathon.
  • the units 31 can form a field generator 3 that is customised to a particular application, and that can be adapted to a new application in a simple manner.
  • Fig. 6 and 7 schematically show examples of suitable field generators 3, which may also be referred to as antennas.
  • the field generators 3 are formed by arrangements of units 31 and 32 respectively.
  • the units 31,32 are used to form an antenna structure of a specific size. Therefore the bases of the units 31 are provided with one or more current paths and are mechanically connected to each other. More specific, in these example the bases are fixated with respect to each other.
  • the bases may be fixated of devices suitable for the specific implementation, for example clamps, screws, glue or any other suitable type.
  • the current paths of at least one set of the units 31 resp. 32 are connected electrically or magnetically in order to behave like a signal magnetic source.
  • the current paths of two units 31 are electrically connected to form a single current loop. That is, a current can flow between the current paths of different units 31.
  • the current paths may be connected such that they form a current loop 320 which extends over a single unit 32 only.
  • the current loops 320 of a set 33,34 of units 32 may be coupled magnetically to behave like a single magnetic source, as is explained below in more detail.
  • Figss. 2 and 3 schematically show an example of an embodiment of a unit 31.
  • the example includes a base 320 which is provided current paths 310-313.
  • the current paths 310-313 of the unit 31 can be connected to current paths of other units 31 in order to form a current loop extending through a plurality of units 31.
  • the base 320 includes at least one, in this example two, surfaces 321, 322 on each of which a set 316, 318 of current paths 310-313 is provided.
  • an arrangement of units 31 will include two energy field generators, each of which generates a magnetic field H.
  • the surfaces 321,322 are parallel to each other.
  • the magnetic fields H from both generators are either in parallel or opposite to each other, depending on the respective direction of the current through the current loops in the generators.
  • an intermediate set 317 of current paths is present, which, as explained below, may be connected to corresponding sets of other units 31 to form an (electro)magnetic receiver.
  • the current paths 310-313 of a set 316-318 are positioned to form, together with current paths of other units 31, at least two different current loops.
  • a generator 3 including a 5-by-5 matrix arrangement of the units 31 shown in figs. 2 and 3, includes five current loops 330- 334 with different orientations and different dimensions.
  • each of the connected current loops extends over at least two units 31 and each unit 31 includes current paths of at least two different current loops 330-334.
  • Each of the current paths 310-313 is provided with electrical contacts 501 near the path ends.
  • the electrical contact 501 may be connected to the electrical contact 501 of another current path 310-313, the other current path 310-313 being present on the same unit 31 or another unit 31.
  • the contacts 501 can for example be dimensioned as shown in fig. 4, and also be used for the connection to a power source 57.
  • the coupling of current paths 301-313 can be done by using for example a coupling elements 502, as shown in fig. 5, with protruding electrical contacts 503, in combination with contact ports 501 on the units 31.
  • Other solutions for electrically connecting the current paths 310-313 are possible, for example by integrating coupling elements with the units 31, and the invention is not limited to the shown example.
  • two separate field generators are formed extending in different planes, in this example the surfaces 321,322 of the base 320.
  • the planes are parallel but at a distance form each other.
  • a receiving antenna will be formed by the intermediate set 317 of current paths of the units 31 extending in parallel with respect to the field generators.
  • one receiving antenna is formed, however also two or more receiving antenna's can be formed in this way.
  • the receiving element 317 situated there will only pick up transponder signals, and the amount of interference from the electromagnetic fields generated by the two current paths 316, 318 is at least reduced. Furthermore, the need to provide a separate receiver 4 as shown in fig. 1 is obviated, and the receiving element 4 as a matter of course always matches with the constructed field generator 3. The space created by obliterating the separate receiver 4 can for example be used to place another integrated combination pf agenerator 3 and receiver 4, in order to create a more evenly distributed field.
  • the example of a sun 31 shown in figs. 2 and 3 includes a current path 311 which crosses at least one, in this example two, other current paths 310,312 and is spaced from those other current paths.
  • the crossing current path 311 is electrically insulated from to the other current paths 310,312 but can be electrically connected to the other current paths 310,312 via the electrical contacts 501.
  • the crossing current paths 311 allows a configuration of current paths 310-313 with repetitive properties. That is, using a plurality of similar units 31, a generator 3 including a number of current loops with different positions and/or orientation and/or dimensions can be obtained.
  • each set 316-318 includes a number of non-parallel current paths, in the example of figs. 2 and 3 four current paths 310-313 in a rectangular arrangement.
  • the current paths 310-313 of each set 316,318 extend from a first edge of the surface 321 to an adjacent edge of the surface 321 which is inclined with respect to the first edge.
  • the arrangement of current paths 310-313 may be implemented in any manner suitable for the specific implementation and the invention is not limited to the shown example. Due to the non-parallel (in the example rectangular) arrangement together with the crossing current paths, a generator with a number of current loops 330-314 of different orientation and dimensions can be obtained automatically as shown in fig. 7.
  • the dimension and number of current loops can be adapted in a simple manner.
  • the arrangement is reduced to a 4x4 matrix and the current paths are suitably connected, an arrangement with four current loops is obtained.
  • the current paths 310-313 may be provided in any arrangement suitable for the specific implementation and the invention is not limited to the shown example.
  • the generator 3 may be implemented in any manner suitable for the specific implementation. As mentioned, figs. 6 and 7 for instance show examples of generators 3 suitable for the example of fig.1.
  • the shown generators 3 include an arrangement, in the example a 2-dimensional matrix-shaped arrangement, of unit 31, 32.
  • the units 31,32 may for instance be implemented as shown in figs. 2-3.
  • the generator 3 includes units 32 of similar shape.
  • the current paths of each unit 32 are electrically insulated from the current paths of the other units 32.
  • the current paths of each unit 32 form a closed current loop 320.
  • the electrical contacts 501 of a unit shown in figs. 2-3 may be connected to other electrical contacts on that same unit
  • the current loop 320 of the units 32 are similar in shape and dimension, and in operation sets 33,34 of the units 32 are provided with a current of similar phase and strength.
  • the combined current loops 320 in a set 33,34 are thus magnetically connected and behave like a single magnetic source.
  • the example of a magnetic field generator 3 shown in fig. 6 includes a plurality of similar shaped current loops 320 connected to a current source 57' in a control device 5' via connections 56.
  • the current source 57' can provide a current to each of the current loops 320.
  • the individual fields of the current loops 320 in the respective set 33,34 combine, in accordance with Stokes' theorem, into a magnetic field H of a single magnetic source.
  • one or more of the current loops 330-334 differ in one or more of their shape, orientation and amount of current with respect to other current loops. 330-334. Accordingly, the fields of the current loops 330- 334 do not combine into a magnetic field H of a single magnetic source, and the respective current loops operate as separate magnetic sources.).
  • each set 33,34 forms a single, controllable, magnetic source of which orientation and position can be varied by changing the current loops in the set in time.
  • the position of the null zone can be varied in time in a flexible manner, and a large degree of variation of this position can be obtained.
  • the generator can be modified in a very simple manner since the need to electrically connect or disconnect the units 32 is obviated
  • current loops 330-334 can be constructed as are shown in the example depicted in fig. 7.
  • the contacts 314-315 at the sides of the matrix-shaped arrangement are connected to each other by means of connectors 319, to close the current loops 330-334.
  • the contacts 314,315 at the bottom of the arrangement are connected to a current source 57 by means of connectors 318.
  • the current paths on the units 31 are arranged such that the generator 3 includes two or more different current loops 330-334.
  • Each unit 31 includes at least two different current paths, each of said different current paths forming a part of a different current loop 330-334.
  • a matrix arrangement of the example of units 31 shown in fig. 2 and 3 may be provided, of which the electrical contacts 501 are connected to electrical contacts of directly adjacent units 31, and of which arrangement the electrical contacts projecting at the edges of the arrangement are connected to contacts 319 at the same edge and on the same unit 31 by means of connectors 319.
  • the contacts at the bottom of the arrangement may for instance be connected to a current source 57 by means of connectors 318.
  • the different current loops 330-334 cross each other, and may have a non-parallel longitudinal axis.
  • the areas enclosed by the current loops 330-334 may have a partial overlap.
  • the current loops 330-334 are electrically insulated with respect to each other and as shown cross each other.
  • the current loops 330-331 and 333-334 have a first longitudinal direction and a second longitudinal direction respectively, said first and second longitudinal directions are substantially perpendicular to each other.
  • the current loops 330-334 are rectangular.
  • the current loops 330-331 and 333-334 have a length larger than their width and the current loop 332 has a substantially square shape.
  • the invention is not limited to the shown example and the current loops may have any shape and orientation suitable for the specific implementation.
  • the current loops 310-313 of a set 316-318 are positioned to form, together with current paths of other units 31, at least two different current loops.
  • a generator 3 including a 5-by-5 matrix arrangement of the units 31 shown in figs. 2 and 3, includes five current loops 330- 334 with different orientations and different dimensions.
  • each of the connected current loops extends over at least two units 31 and each unit 31 includes current paths of at least two different current loops 330-334.
  • the current loops 330-334 each form a separately controllable magnetic source, and are indicated with the continuous, dashed, dotted, dash-dotted, and crossed- dashed lines in fig.
  • the control device 5 controls the current sources 57, and thus the currents flowing through the individual current loops 330-334.
  • the loops that are connected to port 1 and port 5 are perpendicular to each other.
  • the connected current paths form a compound structure that functions as the field generator 3.
  • the examples of figs. 6 and 7 have a field generator which reduces the chance that a transponder 6 passes the monitored area without being detected.
  • a field H created with a generator formed out of units 31 is composed of three perpendicular components.
  • the components are respectively referred to as an x-component Hx in parallel with the horizontal x-axis of the coordinate system 7 shown in figs. 1, an y-component Hy in parallel with the horizontal y-axis of the coordinate system, and a vertical component Hz in parallel with the vertical z-axis of the coordinate system 7.
  • every magnetic field H has zones in which one or more of the components Hx,Hy,Hz are absent. These zones are here from referred to as null zones. In those null zones, at least for some orientations thereof, a transponder 6 will not absorb energy from the energy field..
  • Each type of magnetic field H generated has its own characteristic of null zones.
  • the character of the field generated by a field generator 3 in part depends on the structure of the magnetic source which is formed by the current paths 310-313 on the units 31.
  • the examples of figs. 6 and 7 are constructed to generate a the null zone which has a variable position in the monitored area. Therefore chance that a transponder follows during the path of the null zone nx,nz the entire passage is small, since the position of the null zone varies in operation. Accordingly, the chance that a transponder 6, and the object to which the transponder 6 is attached, passes the monitored area undetected is reduced, through
  • the position of the null zone may vary in time.
  • the control device 5 can activate in a first state a first current loop 330, and in a second state a second current loop 334 with a different orientation.
  • the orientation of the magnetic field H and accordingly, the position of the null zone can be varied in the proximity of the magnetic field generator 3.
  • the control device 5 may, e.g., control the magnetic field generator 3 to switch between two or more different states within a certain time period. In a first state, for instance, one or more magnetic sources at a first position or orientation may be active, while in a second state magnetic sources at a second position or orientation different from the first position or orientation are active. Accordingly, the position and/or orientation of the magnetic field H and hence of the null zone varies when the state of the magnetic field generator 3 is switched by the control device 5.
  • the current loops of the generator may operate as at least two separate magnetic sources.
  • the at least two magnetic sources may for example each consist of a single current source.
  • the example of a magnetic field generator 3 shown in fig. 7 includes a number of separate current loops 330-334 which differ in shape and/or orientation with respect to each other.
  • the current loops 330-334 are indicated with the continuous, dashed, dotted, dash-dotted, and crossed-dashed lines in fig. 7.
  • Each of the current loops 330-334 forms a controllable magnetic source.
  • a first set of current loops 330-332 are mutually different in shape, is oriented with their longitudinal axis in the same direction.
  • a second set of mutually different shaped current loops 333-334 is oriented with their longitudinal axis oriented in a second direction different from the first direction.
  • the first and second direction are perpendicular, and the current loops form a cross-shaped arrangement.
  • the position of the null zone can be varied in time. For instance, in each state, a different selection of the current loops 330-334 may be active. (I.e.
  • the null zone nx,nz may have a position which varies as a function of a distance of the null zone nx,nz from a boundary side of the monitored area, which boundary side forms a boundary of the monitored area in a direction transverse to the direction of passage through the monitored area 2.
  • the null zone is non-horizontal in the direction of passage P, accordingly the position of the null zone varies as a function of the distance from the upright sides 22,32 of the monitored area 2, when all current loops are provided with a current.
  • the null zone has a curved, non-linear, shape, e.g in this example the null zone is curved around two axis perpendicular to the plane in which the current loops 330-334 extend.
  • the dimensions of the current loops 330-334 may, for example be in the order of the distance between the transponder 6 and the generator 3, or larger.
  • the ratio of this distance and the length of the current loops may for instance be smaller than 10:1, such as 2:1 or less, and simulations show that a null zone with a large amount of variation may be obtained if this ratio is about 1:1 or less.
  • the current loops 330-334 have a mirror-symmetric shape of which an axis of symmetry is oriented at angle with respect to the direction of passage P, i.e. non-parallel and not perpendicular to the direction of passage P.
  • the curved null zone is due to this shape of the current loops and orientation of the axis of symmetry.lt should be noted that the above-described embodiments illustrate rather than limit the invention, and various alternatives are possible without departing from the scope of the appended claims.
  • the monitored area may have any suitable size or shape.
  • the monitored area may for example be open or confined at one or more sides.
  • the magnetic field generator 3 may be implemented in any manner suitable for the specific implementation.
  • the system 1 may also be present in an open area, and be used to detect the presence as well as the position of objects in the monitored area 2.
  • the system may be implemented such that the magnetic field generator 3generates a magnetic field H in the entire space, e.g. a storage room or a plant.
  • the monitored area 2 is open at one or more sides, for example by using a magnetic field generator 3, and optionally a detector 4, placed at a central position in the monitored area 2.
  • the magnetic field generator 3 and/or detector 4 may also be positioned in a horizontal arrangement.
  • the magnetic field generator 3 may be positioned lying on the ground, while the detector 4 is oriented horizontally at a distance from the ground, facing the magnetic field generator 3.
  • the detector 4 and/or the magnetic field generator 3 may also be placed in other orientations and/or positions.
  • the units 31, 32 may have every shape suitable for constructing a field generator 3.
  • the units 31, 32 can have a circular form for constructing a cylindrical field generator.
  • the current paths 310-313 may be connected to each other in any matter suitable, e.g. via an electrically conducting connection, via a capacitive connection or otherwise. It should also be noted those skilled in the art will be able to design alternatives without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word 'a' is used as equivalent to the term 'at least one'. The mere fact that certain measures are recited in mutually different claims does not indicate that a combination of these measures cannot be used to advantage.

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Abstract

La présente invention concerne un système de détection d'objets dans une zone qui est surveillée par le système, et une antenne pour l'utilisation dans un tel système. L'antenne comprend une ou plusieurs unités, chacune des unités incluant une base prévue avec au moins un chemin de courant. Les bases desdites unités sont connectées mécaniquement entre elles, et les chemins de courant d'au moins deux desdites unités sont connectés électriquement ou magnétiquement entre eux de manière à ce qu'ils agissent comme une unique source magnétique.
PCT/NL2005/000652 2005-09-09 2005-09-09 Antenne modulaire et système et procédé de détection d'objets Ceased WO2007030003A1 (fr)

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PCT/NL2005/000652 WO2007030003A1 (fr) 2005-09-09 2005-09-09 Antenne modulaire et système et procédé de détection d'objets

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PCT/NL2005/000652 WO2007030003A1 (fr) 2005-09-09 2005-09-09 Antenne modulaire et système et procédé de détection d'objets

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WO2007030003A1 true WO2007030003A1 (fr) 2007-03-15

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9398957B2 (en) 2007-05-01 2016-07-26 Moximed, Inc. Femoral and tibial bases

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6081238A (en) * 1995-05-30 2000-06-27 Sensormatic Electronics Corporation EAS system antenna configuration for providing improved interrogation field distribution
DE20012099U1 (de) * 2000-07-12 2000-12-07 N.V. Nederlandsche Apparatenfabriek Nedap, Groenlo Antenne eines elektromagnetischen Detektionssystems und elektromagnetisches Detektionssystem, versehen mit einer derartigen Antenne
US20010000960A1 (en) * 1998-05-18 2001-05-10 Dettloff Wayne D. Systems and methods for wirelessly projecting power using multiple in-phase current loops

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6081238A (en) * 1995-05-30 2000-06-27 Sensormatic Electronics Corporation EAS system antenna configuration for providing improved interrogation field distribution
US20010000960A1 (en) * 1998-05-18 2001-05-10 Dettloff Wayne D. Systems and methods for wirelessly projecting power using multiple in-phase current loops
DE20012099U1 (de) * 2000-07-12 2000-12-07 N.V. Nederlandsche Apparatenfabriek Nedap, Groenlo Antenne eines elektromagnetischen Detektionssystems und elektromagnetisches Detektionssystem, versehen mit einer derartigen Antenne

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9398957B2 (en) 2007-05-01 2016-07-26 Moximed, Inc. Femoral and tibial bases

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