CA2491256A1 - Nanocrystalline core antenna for eas and rfid applications - Google Patents
Nanocrystalline core antenna for eas and rfid applications Download PDFInfo
- Publication number
- CA2491256A1 CA2491256A1 CA002491256A CA2491256A CA2491256A1 CA 2491256 A1 CA2491256 A1 CA 2491256A1 CA 002491256 A CA002491256 A CA 002491256A CA 2491256 A CA2491256 A CA 2491256A CA 2491256 A1 CA2491256 A1 CA 2491256A1
- Authority
- CA
- Canada
- Prior art keywords
- core
- antenna
- frequency
- nanocrystalline magnetic
- relative permeability
- Prior art date
- Legal status (The legal status 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 status listed.)
- Abandoned
Links
- 238000004804 winding Methods 0.000 claims description 46
- 230000035699 permeability Effects 0.000 claims description 31
- 238000000034 method Methods 0.000 claims description 23
- 239000000696 magnetic material Substances 0.000 claims description 21
- 230000005284 excitation Effects 0.000 claims description 19
- 239000003550 marker Substances 0.000 claims description 19
- 230000005540 biological transmission Effects 0.000 claims description 12
- 230000004044 response Effects 0.000 claims description 12
- 229910045601 alloy Inorganic materials 0.000 claims description 11
- 239000000956 alloy Substances 0.000 claims description 11
- 230000005672 electromagnetic field Effects 0.000 claims description 7
- 239000011810 insulating material Substances 0.000 claims 3
- 239000007787 solid Substances 0.000 claims 3
- 238000001514 detection method Methods 0.000 abstract description 17
- 239000002707 nanocrystalline material Substances 0.000 abstract description 8
- 239000011162 core material Substances 0.000 description 65
- 239000000463 material Substances 0.000 description 15
- 239000003990 capacitor Substances 0.000 description 6
- 229910000859 α-Fe Inorganic materials 0.000 description 6
- 238000010586 diagram Methods 0.000 description 5
- 239000011248 coating agent Substances 0.000 description 4
- 238000000576 coating method Methods 0.000 description 4
- NJPPVKZQTLUDBO-UHFFFAOYSA-N novaluron Chemical compound C1=C(Cl)C(OC(F)(F)C(OC(F)(F)F)F)=CC=C1NC(=O)NC(=O)C1=C(F)C=CC=C1F NJPPVKZQTLUDBO-UHFFFAOYSA-N 0.000 description 4
- 238000000137 annealing Methods 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 230000004907 flux Effects 0.000 description 3
- 230000001747 exhibiting effect Effects 0.000 description 2
- 238000009413 insulation Methods 0.000 description 2
- 238000003475 lamination Methods 0.000 description 2
- KUVIULQEHSCUHY-XYWKZLDCSA-N Beclometasone Chemical compound C1CC2=CC(=O)C=C[C@]2(C)[C@]2(Cl)[C@@H]1[C@@H]1C[C@H](C)[C@@](C(=O)COC(=O)CC)(OC(=O)CC)[C@@]1(C)C[C@@H]2O KUVIULQEHSCUHY-XYWKZLDCSA-N 0.000 description 1
- 239000004593 Epoxy Substances 0.000 description 1
- XJCLWVXTCRQIDI-UHFFFAOYSA-N Sulfallate Chemical compound CCN(CC)C(=S)SCC(Cl)=C XJCLWVXTCRQIDI-UHFFFAOYSA-N 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 239000012774 insulation material Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000007712 rapid solidification Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 101150008563 spir gene Proteins 0.000 description 1
Classifications
-
- H04B5/48—
-
- 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
- H01Q7/06—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 with core of ferromagnetic material
- H01Q7/08—Ferrite rod or like elongated core
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q1/00—Details of, or arrangements associated with, antennas
- H01Q1/12—Supports; Mounting means
- H01Q1/22—Supports; Mounting means by structural association with other equipment or articles
- H01Q1/2208—Supports; Mounting means by structural association with other equipment or articles associated with components used in interrogation type services, i.e. in systems for information exchange between an interrogator/reader and a tag/transponder, e.g. in Radio Frequency Identification [RFID] systems
- H01Q1/2216—Supports; Mounting means by structural association with other equipment or articles associated with components used in interrogation type services, i.e. in systems for information exchange between an interrogator/reader and a tag/transponder, e.g. in Radio Frequency Identification [RFID] systems used in interrogator/reader equipment
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
Abstract
A nanocrystalline core antenna for use in electronic article surveillance (EAS) and radio frequency identification (RFID) systems. The nanocrystalline antenna is constructed from nanocrystalline material and exhibits improved detection range in EAS and RFID
systems compared to conventional antenna configurations.
systems compared to conventional antenna configurations.
Description
NANOCRYSTALLINE CORE ANTENNA FOR EAS AND RFID APPLICATIONS
FIELD OF THE INVENTION
The present invention relates to core antennas, and, in particular, to core antennas for electronic article surveillance (EAS) and radio frequency identification (RFID) systems.
BACKGROUND
EAS and RFID systems are typically utilized to protect and/or track assets. In an EAS
system, an interrogation zone may be established at the perimeter, e.g. at an exit area, of a protected area such as a retail store. The interrogation zone is established by an antenna or antennas positioned adjacent to the interrogation zone.
EAS markers are attached to each asset to be protected. When an article is properly purchased or otherwise authorized for removal from the protected area, the EAS
marker is either removed or deactivated. If the marker is not removed or deactivated and moved into the interrogation zone, the electromagnetic field established by the antennas) causes a response from the EAS marker. An antenna acting as a receiver detects the EAS
marker's response indicating an active marker is in the interrogation zone. An associated controller provides an indication of this condition, e.g., an audio alarm, such that appropriate action can be taken to prevent unauthorized removal of the item to which the marker is affixed from the protected area.
An RF1D system utilizes an RFID marker to track articles for various purposes such as inventory. The RFID marker stores data associated with the article. An RFID
reader may scan for RFID markers by transmitting an interrogation signal at a known frequency. RFID
markers may respond to the interrogation signal with a response signal containing, for example, data associated with the article or an RFID marker ID. The RFID
reader detects the response signal and decodes the data or the RFID tag ID. The RFID reader may be a handheld reader, or a fixed reader by which items carrying an RFID marker pass. A fixed reader may be configured as an antenna located in a pedestal similar to an EAS
system.
Historically, transmitting, receiving, or transceiver antennas in EAS and RFID
systems have been configured as loop-type antennas. Recently, however, magnetic core antenna configurations have been explored for use in such systems: Materials utilized as the core material in core antennas have included ferrite and amorphous magnetic material.
Ferrite material may be provided as a powder, which is blended and compressed into a particular shape and then sintered in a very high temperature oven. The compound becomes a fully crystalline structure after sintering. Ferrite materials have a higher magnetic permeability than air, and have a relatively low saturation flux density compared, for example, to most amorphous materials. Also, ferrite materials that operate at higher RF
(e.g.l5 MHz) frequencies have relatively low permeability andlor saturation flux density.
In contrast to ferrite materials, amorphous magnetic materials lack a distinct crystalline structure. Amorphous magnetic materials e.g., VC6025F available from Vacuumschmelze GmBH Co. (D- 6450 Hanua, Germany), have been successfully utilized in lower frequency EAS applications, e.g., 58 kHz. However, such amorphous magnetic materials do not perform well in the RF frequency range as core loss and permeability decrease performance for frequencies higher than a few 100 kHz.
Accordingly, there is a need for a core antenna for EAS and RFID applications capable of suitable operation frequencies up to the 1tF range. In addition, there is a need for improved performance of a core antenna in the lower frequency range for EAS as an alternative to ferrite or amorphous materials.
SUMMARY OF THE INVENTION
An antenna consistent with the invention for use in an EAS or RFID includes: a core including a nanocrystalline magnetic material, and a coil winding disposed around at least a portion of the core. The antenna may be implemented in an EAS or RFID system for generating an electromagnetic field to interrogate a marker by providing a controller configured to provide an excitation signal to excite the antenna for operation at a given frequency.
A method of establishing extended detection range in an EAS or RFID system consistent with the invention includes: providing a nanocrystalline core antenna including a core and at least one coil winding disposed around at least a portion of the core, the core including nanocrystalline magnetic material; and exciting the antenna for operation up to and including 1tF frequency.
BRIEF DESCRIPTION OF THE DRAWINGS
For a better understanding of the present invention, together with other objects, features and advantages, reference should be made to the following detailed description which should be read in conjunction with the following figures wherein like numerals represent like parts:
FIG. 1 is block diagram of an exemplary EAS system consistent with the invention;
FIG. 2 is a block diagram of one embodiment of a nanocrystalline magnetic core antenna consistent with the invention;
FIG. 3 is one exemplary circuit diagram of a controller for use with the system of FIG.1;
FIG. 4 is a perspective view of an exemplary nanocrystalline core antenna consistent with the invention;
FIG. 5 is a partial cross-sectional view of the nanocrystalline core of FIG. 4 showing the insulated laminations and taken along the line 5-5 of FIG. 4.
FIG. 6A is a perspective view of another exemplary nanocrystalline core antenna consistent with the invention illustrating a resonant primary coil winding and a non-resonant secondary coil winding for transmitter, receiver, or transceiver mode operation.
FIG. 6B is an perspective view of a portion of the antenna of FIG. 6A showing the primary and secondary windings in greater detail FIG. 7 is a plot of magnetic flux density versus magnetic field intensity for an exemplary nanocrystalline core antenna consistent with the invention.
PIG. S is a plot of relative per~r~eability veisas inagnetv field ititan~ii.y for an exemplary nanocrystalline core antenna consistent with the invention.
FIGS. 9A-9C are detection performance plots illustrating detection range for an EAS
tag in lateral, horizontal, and vertical orientations, respectively, in an exemplary system consistent with the invention.
DETAILED DESCRIPTION
For simplicity and ease of explanation, the present invention will be described herein in connection with various exemplary embodiments thereof associated with EAS
systems. A
core antenna consistent with the present invention may, however, be used in connection with an ItFID system. It is to be understood, therefore, that the embodiments described herein are presented by way of illustration, not of limitation.
Turning to FIG. 1, there is illustrated an EAS system 100 including a nanocrystalline core antenna 109 consistent with the invention. The EAS system 100 generally includes a controller 110 and a pedestal 106 for housing the core antenna 109. The controller 110 is shown separate from the pedestal 106 for clarity but may be included in the pedestal housing.
In the exemplary embodiment of FIG. 1, the antenna 109 is configured as a transceiver and the associated controller 110 includes proper control and switching to switch from transmitting to receiving functions at predetermined time intervals. Those skilled in the art will recognize that there may be a separate transmitting antenna and receiving antenna located on separate sides of the interrogation zone 104.
An EAS marker 102 is placed, e.g, at a manufacturing facility or retail establishment, on each item or asset to be protected. If the marker is not removed or deactivated prior to entering an interrogation zone 104, the electromagnetic field established by the antenna will cause a response from the EAS marker 102. The core antenna 109 acting as a receiver will receive this response, and the controller 110 will detect the EAS marker response indicating that the marker is in the interrogation zone 104.
Turning to FIG. 2, a block diagram 200 of one embodiment of a nanocrystalline magnetic core antenna consistent with the invention configured as a transceiver antenna is illustrated. In the illustrated embodiment 200, a winding is placed around the nanocrystalline magnetic core and coupled to a series resonating capacitor C2. The core antenna with this winding is represented by the inductor L2, the resistor R2, and the series resonating capacitor C2 in the series RLC circuit 218. As is known to those skilled in the art, the value of the series resonating capacitor C2 is selected to resonate or tune the antenna circuit at the desired operating frequency. Another winding, represented by L1, may be placed around the core antenna and then coupled to the transmission line or cable (depending on the operating frequency) 212, which is in turn coupled to a controller 210 having appropriate excitation and detection circuitry to support both transmit and receive functions. The winding L1 is inductively coupled to the series resonating RLC circuit 218.
The controller 210 may be adapted to operate using pulsed or continuous waveform detection schemes, including swept frequency, frequency hopping, frequency shift keying, amplitude modulation, frequency modulation, and the like depending on the specific design of the system. For instance, the controller 210 may provide a limited duration pulse at a given operating frequency, e.g., 8.2 MHz, to the transmission line cable 212 during transmission. The pulse is transmitted via the transmission line cable 212 to the core antenna load. The transmission line cable may have an impedance, e.g., 50 ohms, that matches the signal generator impedance to prevent reflections. At lower frequencies, e.g.
58 kHz, the transmission Iine or cable is not important in impedance matching. In addition, the impedance transformer L1 may match the resonant core load impedance of the series RLC
circuit 218 to the transmission cable 212.
FIG. 3 is a more detailed block diagram of an exemplary controller 310 configured for operation using a pulse detection scheme. The controller 310 may include a transmitter drive circuit 318, which includes signal generator 311 and transmitter amplifier 312. The signal generator 311 supplies an input signal to the transmitter 312 at a desired frequency such as RF frequency levels. The term "RF" as used herein refers to a range of frequencies between 9KHz and 300MHz.
The transmitter 312 drives the nanocrystalline magnetic core antenna represented by inductor LA, resistor RC, and resonating capacitor CR. The transmitter drive circuit 318 thus provides a burst to the core antenna at a given frequency for a short period of time to produce a sufficient electromagnetic field at a sufficient distance from the core antenna in an associated interrogation zone. A marker in the interrogation zone excited by this electromagnetic field produces a sufficient response signal for detection when the core antenna is connected to the receiver circuit portion of the controller 310.
After a short delay following the transmission burst, the nanocrystalline magnetic core antenna is coupled to the receiver circuit 322 when the switch controller 324 instructs the switch S1 to open. The switch controller 324 effectively switches the core antenna into and out of transmit and receive modes. During the transmitter pulse, the receiver circuit 322 is isolated from the antenna load at node 330 through the decoupling network formed by capacitor CDEC and resistor RDEC and the input protection circuit 334. After the transmission pulse, there is sufficient delay to allow the energy from the transmitter circuit 318 to fully dissipate. The switch controller 324 then disconnects the transmitter amplifier 312 from the antenna by opening switch S 1. The alternating transmit and receive modes continue in such a pulse mode.
A perspective view of a nanocrystalline magnetic core antenna 400 consistent with the invention is illustrated in FIG. 4. The core antenna 400 may be utilized as the transceiver antenna of the system of FIGS. 1 and 2, a transmitter antenna, or a receiver antenna. The nanocrystalline magnetic core antenna 400 includes a core assembly 404 with a coil winding 406 thereon. The coil winding 406 may be coupled to a transmission line and controller as previously detailed. Those skilled in the art will recognize that the dimension of a core antenna consistent with the invention may vary depending on application and performance requirements. In exemplary embodiments, the core may have a length in a range from 20 to 80 cm, and may have a cross-sectional area from 0.02 to 1 cm2.
FIG. 5 is a partial cross sectional view of the core assembly 404 taken along the line 5-5 of FIG. 4. In the illustrated exemplary embodiment, the core assembly 404 generally includes stacked ribbons 508 of nanocrystalline material laminated together with a suitable insulation coating 510. The insulation coating 510 electrically isolates each ribbon 508 from adjacent ribbons to reduce eddy current losses.
As will be recognized by those skilled in the art, nanocrystalline material begins in an amorphous state achieved through rapid solidification techniques. After casting, while the material is still very ductile, a suitable coating such as Si02 may be applied to the material.
This coating remains effective after annealing and prevents eddy currents in the laminate core. The material may be cut to a desired shape and bulk annealed to form the nanocrystalline state. The resulting nanocrystalline material exhibits excellent high frequency behavior, and is characterized by constituent grain sizes in the nanometer range.
The term "nanocrystalline material" as used herein refers to material including grains having a maximum dimension less than or equal to 40nm. Some materials have a maximum dimension in a range from about lOnm to 40nm.
Exemplary nanocrystalline materials useful in a nanocrystalline core antenna consistent with the invention include alloys such as FeCuNbSiB, FeZrNbCu, and FeCoZrBCu. These alloys are commercially available under the names FINEMET, NANOPEIRM, and HITPERM, respectively. The insulation material 510 may be any suitable material that can withstand the annealing conditions, since it is preferable to coat the material before annealing. Epoxy may be used for bonding the lamination stack after the material is annealed. This also provides mechanical rigidity to the core assembly, thus preventing mechanical deformation or fracture. Alternatively, the nanocrystalline stack may be placed in a rigid plastic housing.
FIGS. 6A and 6B are perspective views of another exemplary nanocrystalline magnetic core antenna 600 consistent with the invention. As shown, the core antenna 600 includes a nanocrystalline core assembly 602 with a primary resonant coil winding 604 and a secondary non-resonant coil winding 606. A capacitor 608, shown particularly in FIG. 6B, is coupled to the primary winding 604 for tuning the resonant frequency of the primary winding.
Providing multiple windings 604, 606 on a single core 602 allows use of the core to transmit at one frequency and receive at another frequency as long as sufficient frequency separation is provided. Using two windings operating at separate frequencies, such as 58 kHz and 13.56 MHz, also allows use of a single antenna as a transmitter and/or receiver at either frequency so that the antenna assembly can be plugged into a system operating at either frequency without special tuning. Additionally, multiple windings may be used such that the transmitter winding is tuned to 13.56 MHz and the receiver winding is tuned to 6.78 MHz (half frequency) to facilitate operation using a frequency division scheme.
Turning to FIG. 7, there is provided a BH plot 700 for an exemplary nanocrystalline magnetic core antenna consistent with the invention constructed as shown in FIG. 4 using a FINEMET core. The exemplary nanocrystalline magnetic core antenna was 60 cm long by 0.5 cm wide, by 0.5 cm high and operated at 1 KHz. In general, the plot includes a linear region at fields below saturation (H fields between about +/- 170 A/m) and a flat region at saturation (H fields above and below about +/- 250 A/m). The slope of the linear region determines the permeability. In general, a higher permeability results in a more sensitive antenna when configured to act as a receiver antenna.
FIG. 8 is a plot 800 of relative permeability versus H-field in A/m at a frequency of 1 kHz for the same exemplary 60 cm x 0.5 cm x 0.5 cm nanocrystalline magnetic core antenna exhibiting the BH plot of FIG. 7. As indicated, the relative permeability is about 5000 or higher at H fields between 0 and about 100 A/m. The permeability decreases relatively linearly until saturation at about 250 A/m where it begins to drop off even further. Of course, as the antenna operating frequency increases, permeability decreases.
Nonetheless, high permeability is maintained compared to conventional core antenna configurations. For example, the same exemplary 60 cm x 0.5 cm x 0.5 cm nanocrystalline magnetic core antenna exhibiting the BH plot of FIG. 7 and permeability characteristic of FIG. 8 and operated at frequencies from 8.2 to 13.56MHz exhibits a minimum relative permeability of 300. Due to the relatively high permeability and saturation level of nanocrystalline material, as indicated, for example, in FIGS. 7 and 8, a nanocrystalline core antenna used as a receiver antenna exhibits increased detection performance compared to conventional core antenna configurations.
FIGS. 9A-9C are detection performance plots 900, 902, 904 illustrating detection range for an EAS tag in lateral, horizontal, and vertical orientations, respectively, associated with an axially arranged pair of nanocrystalline magnetic core antennas consistent with the invention. The two nanocrystalline magnetic core antennas were 60 cm long x 0.5 cm wide x 0.5 cm thick and provided in a 58 kHz detection configuration. The dimensions of the plots in each of FIGS. 9A-9C correspond to the height and width dimensions of the tested area.
The shaded area of each figure shows detection of an EAS tag. Non,shaded areas are areas in which an EAS tag is not detected. As shown, the exemplary antenna configuration exhibits a detection range between about 0 cm and 90 cm over a large height range from about 0 cm to 150 cm. In addition, the detection rate, also referred to as the pick rate, for the lateral orientation was 93.1%. The pick rate for the horizontal orientation was 79.3%, and the pick rate for the vertical orientation was 95.6%. The exhibited detection range and pick rates compare favorably with those of amorphous core antennas.
There is thus provided a nanocrystalline core antenna for use in EAS and RFID
systems. The nanocrystalline antenna is constructed from nanocrystalline material and exhibits excellent performance characteristics at 1tF frequencies. The performance of the antenna results in improved detection range in EAS and RFID systems compared to conventional antenna configurations.
The embodiments that have been described herein, however, are but some of the several which utilize this invention and are set forth here by way of illustration but not of limitation. It is obvious that many other embodiments, which will be readily apparent to ~l~Jb skilled ua t<':e ar t, :ray be :rade w itl~.out dep:~irg materially from u~:e spir it t~u~d Jvoire cf the invention as defined in the appended claims.
FIELD OF THE INVENTION
The present invention relates to core antennas, and, in particular, to core antennas for electronic article surveillance (EAS) and radio frequency identification (RFID) systems.
BACKGROUND
EAS and RFID systems are typically utilized to protect and/or track assets. In an EAS
system, an interrogation zone may be established at the perimeter, e.g. at an exit area, of a protected area such as a retail store. The interrogation zone is established by an antenna or antennas positioned adjacent to the interrogation zone.
EAS markers are attached to each asset to be protected. When an article is properly purchased or otherwise authorized for removal from the protected area, the EAS
marker is either removed or deactivated. If the marker is not removed or deactivated and moved into the interrogation zone, the electromagnetic field established by the antennas) causes a response from the EAS marker. An antenna acting as a receiver detects the EAS
marker's response indicating an active marker is in the interrogation zone. An associated controller provides an indication of this condition, e.g., an audio alarm, such that appropriate action can be taken to prevent unauthorized removal of the item to which the marker is affixed from the protected area.
An RF1D system utilizes an RFID marker to track articles for various purposes such as inventory. The RFID marker stores data associated with the article. An RFID
reader may scan for RFID markers by transmitting an interrogation signal at a known frequency. RFID
markers may respond to the interrogation signal with a response signal containing, for example, data associated with the article or an RFID marker ID. The RFID
reader detects the response signal and decodes the data or the RFID tag ID. The RFID reader may be a handheld reader, or a fixed reader by which items carrying an RFID marker pass. A fixed reader may be configured as an antenna located in a pedestal similar to an EAS
system.
Historically, transmitting, receiving, or transceiver antennas in EAS and RFID
systems have been configured as loop-type antennas. Recently, however, magnetic core antenna configurations have been explored for use in such systems: Materials utilized as the core material in core antennas have included ferrite and amorphous magnetic material.
Ferrite material may be provided as a powder, which is blended and compressed into a particular shape and then sintered in a very high temperature oven. The compound becomes a fully crystalline structure after sintering. Ferrite materials have a higher magnetic permeability than air, and have a relatively low saturation flux density compared, for example, to most amorphous materials. Also, ferrite materials that operate at higher RF
(e.g.l5 MHz) frequencies have relatively low permeability andlor saturation flux density.
In contrast to ferrite materials, amorphous magnetic materials lack a distinct crystalline structure. Amorphous magnetic materials e.g., VC6025F available from Vacuumschmelze GmBH Co. (D- 6450 Hanua, Germany), have been successfully utilized in lower frequency EAS applications, e.g., 58 kHz. However, such amorphous magnetic materials do not perform well in the RF frequency range as core loss and permeability decrease performance for frequencies higher than a few 100 kHz.
Accordingly, there is a need for a core antenna for EAS and RFID applications capable of suitable operation frequencies up to the 1tF range. In addition, there is a need for improved performance of a core antenna in the lower frequency range for EAS as an alternative to ferrite or amorphous materials.
SUMMARY OF THE INVENTION
An antenna consistent with the invention for use in an EAS or RFID includes: a core including a nanocrystalline magnetic material, and a coil winding disposed around at least a portion of the core. The antenna may be implemented in an EAS or RFID system for generating an electromagnetic field to interrogate a marker by providing a controller configured to provide an excitation signal to excite the antenna for operation at a given frequency.
A method of establishing extended detection range in an EAS or RFID system consistent with the invention includes: providing a nanocrystalline core antenna including a core and at least one coil winding disposed around at least a portion of the core, the core including nanocrystalline magnetic material; and exciting the antenna for operation up to and including 1tF frequency.
BRIEF DESCRIPTION OF THE DRAWINGS
For a better understanding of the present invention, together with other objects, features and advantages, reference should be made to the following detailed description which should be read in conjunction with the following figures wherein like numerals represent like parts:
FIG. 1 is block diagram of an exemplary EAS system consistent with the invention;
FIG. 2 is a block diagram of one embodiment of a nanocrystalline magnetic core antenna consistent with the invention;
FIG. 3 is one exemplary circuit diagram of a controller for use with the system of FIG.1;
FIG. 4 is a perspective view of an exemplary nanocrystalline core antenna consistent with the invention;
FIG. 5 is a partial cross-sectional view of the nanocrystalline core of FIG. 4 showing the insulated laminations and taken along the line 5-5 of FIG. 4.
FIG. 6A is a perspective view of another exemplary nanocrystalline core antenna consistent with the invention illustrating a resonant primary coil winding and a non-resonant secondary coil winding for transmitter, receiver, or transceiver mode operation.
FIG. 6B is an perspective view of a portion of the antenna of FIG. 6A showing the primary and secondary windings in greater detail FIG. 7 is a plot of magnetic flux density versus magnetic field intensity for an exemplary nanocrystalline core antenna consistent with the invention.
PIG. S is a plot of relative per~r~eability veisas inagnetv field ititan~ii.y for an exemplary nanocrystalline core antenna consistent with the invention.
FIGS. 9A-9C are detection performance plots illustrating detection range for an EAS
tag in lateral, horizontal, and vertical orientations, respectively, in an exemplary system consistent with the invention.
DETAILED DESCRIPTION
For simplicity and ease of explanation, the present invention will be described herein in connection with various exemplary embodiments thereof associated with EAS
systems. A
core antenna consistent with the present invention may, however, be used in connection with an ItFID system. It is to be understood, therefore, that the embodiments described herein are presented by way of illustration, not of limitation.
Turning to FIG. 1, there is illustrated an EAS system 100 including a nanocrystalline core antenna 109 consistent with the invention. The EAS system 100 generally includes a controller 110 and a pedestal 106 for housing the core antenna 109. The controller 110 is shown separate from the pedestal 106 for clarity but may be included in the pedestal housing.
In the exemplary embodiment of FIG. 1, the antenna 109 is configured as a transceiver and the associated controller 110 includes proper control and switching to switch from transmitting to receiving functions at predetermined time intervals. Those skilled in the art will recognize that there may be a separate transmitting antenna and receiving antenna located on separate sides of the interrogation zone 104.
An EAS marker 102 is placed, e.g, at a manufacturing facility or retail establishment, on each item or asset to be protected. If the marker is not removed or deactivated prior to entering an interrogation zone 104, the electromagnetic field established by the antenna will cause a response from the EAS marker 102. The core antenna 109 acting as a receiver will receive this response, and the controller 110 will detect the EAS marker response indicating that the marker is in the interrogation zone 104.
Turning to FIG. 2, a block diagram 200 of one embodiment of a nanocrystalline magnetic core antenna consistent with the invention configured as a transceiver antenna is illustrated. In the illustrated embodiment 200, a winding is placed around the nanocrystalline magnetic core and coupled to a series resonating capacitor C2. The core antenna with this winding is represented by the inductor L2, the resistor R2, and the series resonating capacitor C2 in the series RLC circuit 218. As is known to those skilled in the art, the value of the series resonating capacitor C2 is selected to resonate or tune the antenna circuit at the desired operating frequency. Another winding, represented by L1, may be placed around the core antenna and then coupled to the transmission line or cable (depending on the operating frequency) 212, which is in turn coupled to a controller 210 having appropriate excitation and detection circuitry to support both transmit and receive functions. The winding L1 is inductively coupled to the series resonating RLC circuit 218.
The controller 210 may be adapted to operate using pulsed or continuous waveform detection schemes, including swept frequency, frequency hopping, frequency shift keying, amplitude modulation, frequency modulation, and the like depending on the specific design of the system. For instance, the controller 210 may provide a limited duration pulse at a given operating frequency, e.g., 8.2 MHz, to the transmission line cable 212 during transmission. The pulse is transmitted via the transmission line cable 212 to the core antenna load. The transmission line cable may have an impedance, e.g., 50 ohms, that matches the signal generator impedance to prevent reflections. At lower frequencies, e.g.
58 kHz, the transmission Iine or cable is not important in impedance matching. In addition, the impedance transformer L1 may match the resonant core load impedance of the series RLC
circuit 218 to the transmission cable 212.
FIG. 3 is a more detailed block diagram of an exemplary controller 310 configured for operation using a pulse detection scheme. The controller 310 may include a transmitter drive circuit 318, which includes signal generator 311 and transmitter amplifier 312. The signal generator 311 supplies an input signal to the transmitter 312 at a desired frequency such as RF frequency levels. The term "RF" as used herein refers to a range of frequencies between 9KHz and 300MHz.
The transmitter 312 drives the nanocrystalline magnetic core antenna represented by inductor LA, resistor RC, and resonating capacitor CR. The transmitter drive circuit 318 thus provides a burst to the core antenna at a given frequency for a short period of time to produce a sufficient electromagnetic field at a sufficient distance from the core antenna in an associated interrogation zone. A marker in the interrogation zone excited by this electromagnetic field produces a sufficient response signal for detection when the core antenna is connected to the receiver circuit portion of the controller 310.
After a short delay following the transmission burst, the nanocrystalline magnetic core antenna is coupled to the receiver circuit 322 when the switch controller 324 instructs the switch S1 to open. The switch controller 324 effectively switches the core antenna into and out of transmit and receive modes. During the transmitter pulse, the receiver circuit 322 is isolated from the antenna load at node 330 through the decoupling network formed by capacitor CDEC and resistor RDEC and the input protection circuit 334. After the transmission pulse, there is sufficient delay to allow the energy from the transmitter circuit 318 to fully dissipate. The switch controller 324 then disconnects the transmitter amplifier 312 from the antenna by opening switch S 1. The alternating transmit and receive modes continue in such a pulse mode.
A perspective view of a nanocrystalline magnetic core antenna 400 consistent with the invention is illustrated in FIG. 4. The core antenna 400 may be utilized as the transceiver antenna of the system of FIGS. 1 and 2, a transmitter antenna, or a receiver antenna. The nanocrystalline magnetic core antenna 400 includes a core assembly 404 with a coil winding 406 thereon. The coil winding 406 may be coupled to a transmission line and controller as previously detailed. Those skilled in the art will recognize that the dimension of a core antenna consistent with the invention may vary depending on application and performance requirements. In exemplary embodiments, the core may have a length in a range from 20 to 80 cm, and may have a cross-sectional area from 0.02 to 1 cm2.
FIG. 5 is a partial cross sectional view of the core assembly 404 taken along the line 5-5 of FIG. 4. In the illustrated exemplary embodiment, the core assembly 404 generally includes stacked ribbons 508 of nanocrystalline material laminated together with a suitable insulation coating 510. The insulation coating 510 electrically isolates each ribbon 508 from adjacent ribbons to reduce eddy current losses.
As will be recognized by those skilled in the art, nanocrystalline material begins in an amorphous state achieved through rapid solidification techniques. After casting, while the material is still very ductile, a suitable coating such as Si02 may be applied to the material.
This coating remains effective after annealing and prevents eddy currents in the laminate core. The material may be cut to a desired shape and bulk annealed to form the nanocrystalline state. The resulting nanocrystalline material exhibits excellent high frequency behavior, and is characterized by constituent grain sizes in the nanometer range.
The term "nanocrystalline material" as used herein refers to material including grains having a maximum dimension less than or equal to 40nm. Some materials have a maximum dimension in a range from about lOnm to 40nm.
Exemplary nanocrystalline materials useful in a nanocrystalline core antenna consistent with the invention include alloys such as FeCuNbSiB, FeZrNbCu, and FeCoZrBCu. These alloys are commercially available under the names FINEMET, NANOPEIRM, and HITPERM, respectively. The insulation material 510 may be any suitable material that can withstand the annealing conditions, since it is preferable to coat the material before annealing. Epoxy may be used for bonding the lamination stack after the material is annealed. This also provides mechanical rigidity to the core assembly, thus preventing mechanical deformation or fracture. Alternatively, the nanocrystalline stack may be placed in a rigid plastic housing.
FIGS. 6A and 6B are perspective views of another exemplary nanocrystalline magnetic core antenna 600 consistent with the invention. As shown, the core antenna 600 includes a nanocrystalline core assembly 602 with a primary resonant coil winding 604 and a secondary non-resonant coil winding 606. A capacitor 608, shown particularly in FIG. 6B, is coupled to the primary winding 604 for tuning the resonant frequency of the primary winding.
Providing multiple windings 604, 606 on a single core 602 allows use of the core to transmit at one frequency and receive at another frequency as long as sufficient frequency separation is provided. Using two windings operating at separate frequencies, such as 58 kHz and 13.56 MHz, also allows use of a single antenna as a transmitter and/or receiver at either frequency so that the antenna assembly can be plugged into a system operating at either frequency without special tuning. Additionally, multiple windings may be used such that the transmitter winding is tuned to 13.56 MHz and the receiver winding is tuned to 6.78 MHz (half frequency) to facilitate operation using a frequency division scheme.
Turning to FIG. 7, there is provided a BH plot 700 for an exemplary nanocrystalline magnetic core antenna consistent with the invention constructed as shown in FIG. 4 using a FINEMET core. The exemplary nanocrystalline magnetic core antenna was 60 cm long by 0.5 cm wide, by 0.5 cm high and operated at 1 KHz. In general, the plot includes a linear region at fields below saturation (H fields between about +/- 170 A/m) and a flat region at saturation (H fields above and below about +/- 250 A/m). The slope of the linear region determines the permeability. In general, a higher permeability results in a more sensitive antenna when configured to act as a receiver antenna.
FIG. 8 is a plot 800 of relative permeability versus H-field in A/m at a frequency of 1 kHz for the same exemplary 60 cm x 0.5 cm x 0.5 cm nanocrystalline magnetic core antenna exhibiting the BH plot of FIG. 7. As indicated, the relative permeability is about 5000 or higher at H fields between 0 and about 100 A/m. The permeability decreases relatively linearly until saturation at about 250 A/m where it begins to drop off even further. Of course, as the antenna operating frequency increases, permeability decreases.
Nonetheless, high permeability is maintained compared to conventional core antenna configurations. For example, the same exemplary 60 cm x 0.5 cm x 0.5 cm nanocrystalline magnetic core antenna exhibiting the BH plot of FIG. 7 and permeability characteristic of FIG. 8 and operated at frequencies from 8.2 to 13.56MHz exhibits a minimum relative permeability of 300. Due to the relatively high permeability and saturation level of nanocrystalline material, as indicated, for example, in FIGS. 7 and 8, a nanocrystalline core antenna used as a receiver antenna exhibits increased detection performance compared to conventional core antenna configurations.
FIGS. 9A-9C are detection performance plots 900, 902, 904 illustrating detection range for an EAS tag in lateral, horizontal, and vertical orientations, respectively, associated with an axially arranged pair of nanocrystalline magnetic core antennas consistent with the invention. The two nanocrystalline magnetic core antennas were 60 cm long x 0.5 cm wide x 0.5 cm thick and provided in a 58 kHz detection configuration. The dimensions of the plots in each of FIGS. 9A-9C correspond to the height and width dimensions of the tested area.
The shaded area of each figure shows detection of an EAS tag. Non,shaded areas are areas in which an EAS tag is not detected. As shown, the exemplary antenna configuration exhibits a detection range between about 0 cm and 90 cm over a large height range from about 0 cm to 150 cm. In addition, the detection rate, also referred to as the pick rate, for the lateral orientation was 93.1%. The pick rate for the horizontal orientation was 79.3%, and the pick rate for the vertical orientation was 95.6%. The exhibited detection range and pick rates compare favorably with those of amorphous core antennas.
There is thus provided a nanocrystalline core antenna for use in EAS and RFID
systems. The nanocrystalline antenna is constructed from nanocrystalline material and exhibits excellent performance characteristics at 1tF frequencies. The performance of the antenna results in improved detection range in EAS and RFID systems compared to conventional antenna configurations.
The embodiments that have been described herein, however, are but some of the several which utilize this invention and are set forth here by way of illustration but not of limitation. It is obvious that many other embodiments, which will be readily apparent to ~l~Jb skilled ua t<':e ar t, :ray be :rade w itl~.out dep:~irg materially from u~:e spir it t~u~d Jvoire cf the invention as defined in the appended claims.
Claims (62)
1. An EAS or RFID system comprising:
an antenna comprising a core and at least one coil winding disposed around at least a portion of said core, said core comprising nanocrystalline magnetic material;
and a controller coupled to said at least one coil winding to provide an excitation signal to said winding.
an antenna comprising a core and at least one coil winding disposed around at least a portion of said core, said core comprising nanocrystalline magnetic material;
and a controller coupled to said at least one coil winding to provide an excitation signal to said winding.
2. The system of claim 1, wherein said core comprises a laminated core assembly comprising a plurality of nanocrystalline magnetic ribbons.
3. The system of claim 2, wherein said plurality of nanocrystalline magnetic ribbons are stacked to form a substantially elongated solid rectangular laminated core assembly.
4. The system of claim 2, wherein said laminated core assembly comprises an insulating material disposed between each of said nanocrystalline magnetic ribbons.
signal has a frequency of 1kHz.
signal has a frequency of 1kHz.
5. The system of claim 1, wherein a relative permeability of said core is greater than 5000 for associated H-field values from about 0 A/m to about 100 A/m when said excitation signal has a frequency of 1kHz.
6. The system of claim 1, wherein a relative permeability of said core is greater than or equal to 300 when said excitation signal has a frequency of 13.56MHz.
7. The system of claim 1, wherein a relative permeability of said core is greater than or equal to 300 when said excitation signal has a frequency from 8.2MHz to 13.56MHz.
8. The system of claim 1, wherein said core has a length in a range from 20 to 80 cm, and a cross-sectional area in a range from 0.02 to 1 cm2.
9 9. The system of claim 8, wherein a relative permeability of said core is greater than 5000 for associated H-field values from about 0 A/m to about 100 A/m when said excitation signal has a frequency of 1kHz.
10. The system of claim 8, wherein a relative permeability of said core is greater than or equal to 300 when said excitation signal has a frequency of 13.56MHz.
11. The system of claim 8, wherein a relative permeability of said core is greater than or equal to 300 when said excitation signal has a frequency from 8.2MHz to 13.56MHz.
12. The system of claim 1, further comprising a transmission line having one end coupled to said controller and another end coupled to said winding.
13. The system of claim 12, wherein said transmission line has a first impedance level and a signal generator in said controller has a second impedance level, wherein said first impedance level and said second impedance level are substantially equal.
14. The system of claim 1, said system comprising a plurality of said coil windings.
15. The system of claim 14, wherein a first one of said coil windings is inductively coupled to a second one of said coil windings.
16. The system of claim 14, wherein first and second ones of said coil windings are configured for operation at different associated frequencies.
17. The system of claim 16, wherein said first coil winding is configured for transmitting at a first frequency and said second coil winding is configured for receiving a response from an EAS or RFID tag at a second frequency different from said first frequency.
18. The system of claim 1, wherein said antenna is configured as a transceiver antenna to generate said electromagnetic field and to detect a marker within said electromagnetic field, and wherein said controller comprises:
a transmitter driver circuit configured to provide said excitation signal;
a receiver circuit configured to receive said characteristic response signal from said marker, and a switch configured to switch said first coil winding of wire coil between said transmitter driver circuit and said receiver circuit.
a transmitter driver circuit configured to provide said excitation signal;
a receiver circuit configured to receive said characteristic response signal from said marker, and a switch configured to switch said first coil winding of wire coil between said transmitter driver circuit and said receiver circuit.
19. The system of claim 1, wherein said excitation signal has a frequency in a range from 9KHz to 300MHz.
20. The system of claim 1, wherein said nanocrystalline magnetic material comprises grains having a maximum dimension in a range from 10nm to 40nm.
21. The system of claim 1, wherein said nanocrystalline magnetic material is an alloy comprising FeCuNbSiB.
22. The system of claim 1, wherein said nanocrystalline magnetic material is an alloy comprising FeZrNbCu.
23. The system of claim 1, wherein said nanocrystalline magnetic material is an alloy comprising FeCoZrBCu.
24. An antenna for use in an EAS or RFID system, said antenna comprising:
a core comprising nanocrystalline magnetic material; and at least one coil winding disposed around at least a portion of said core.
a core comprising nanocrystalline magnetic material; and at least one coil winding disposed around at least a portion of said core.
25. The antenna of claim 24, wherein said core comprises a laminated core assembly comprising a plurality of nanocrystalline magnetic ribbons.
26. The antenna of claim 25, wherein said plurality of nanocrystalline magnetic ribbons are stacked to form a substantially elongated solid rectangular laminated core assembly.
27. The antenna of claim 25, wherein said laminated core assembly comprises an insulating material disposed between each of said nanocrystalline magnetic ribbons.
28. The antenna of claim 24, wherein a relative permeability of said core is greater than 5000 for associated H-field values from about 0 A/m to about 100 A/m when excited at a frequency of 1kHz.
29. The antenna of claim 24, wherein a relative permeability of said core is greater than or equal to 300 when excited at a frequency of 13.56MHz.
30. The antenna of claim 24, wherein a relative permeability of said core is greater than or equal to 300 when excited at a frequency from 8.2MHz to 13.56MHz.
31. The antenna of claim 24, wherein said core has a length in a range from 20 to 80 cm, and a cross-sectional area in range from 0.02 to 1 cm2.
32. The antenna of claim 31, wherein a relative permeability of said core is greater than 5000 for associated H-field values from about 0 A/m to about 100 A/m when excited at a frequency of 1kHz.
33. The antenna of claim 31, wherein a relative permeability of said core is greater than or equal to 300 when excited at a frequency of 13.56MHz.
34. The antenna of claim 31, wherein a relative permeability of said core is greater than or equal to 300 when excited at a frequency from 8.2MHz to 13.56MHz.
35. The antenna of claim 24, said antenna comprising a plurality of said coil windings.
36. The antenna of claim 35, wherein a first one of said coil windings is inductively coupled to a second one of said coil windings.
37. The antenna of claim 35, wherein first and second ones of said coil windings are configured for operation at different associated frequencies.
38. The antenna of claim 37, wherein said first coil winding is configured for transmitting at a first frequency and said second coil winding is configured for receiving a response from an EAS or RFID tag at a second frequency different from said first frequency.
39. The antenna of claim 24, wherein said nanocrystalline magnetic material comprises grains having a maximum dimension of in a range from 10nm to 40nm.
40. The antenna of claim 24, wherein said nanocrystalline magnetic material is an alloy comprising FeCuNbSiB.
41. The antenna of claim 24, wherein said nanocrystalline magnetic material is an alloy comprising FeZrNbCu.
42. The antenna of claim 24, wherein said nanocrystalline magnetic material is an alloy comprising FeCoZrBCu.
43. A method of establishing an interrogation zone in an EAS or RFID system, said method comprising:
providing a nanocrystalline core antenna comprising a core and at least one coil winding disposed around at least a portion of said core, said core comprising nanocrystalline magnetic material; and exciting said coil winding with an excitation signal.
providing a nanocrystalline core antenna comprising a core and at least one coil winding disposed around at least a portion of said core, said core comprising nanocrystalline magnetic material; and exciting said coil winding with an excitation signal.
44. The method of claim 43, wherein said core comprises a laminated core assembly comprising a plurality of nanocrystalline magnetic ribbons.
45. The method of claim 44, wherein said plurality of nanocrystalline magnetic ribbons are stacked to form a substantially elongated solid rectangular laminated core assembly.
46. The method of claim 44, wherein said laminated core assembly comprises an insulating material disposed between each of said nanocrystalline magnetic ribbons.
47. The method of claim 43, wherein a relative permeability of said core is greater than 5000 for associated H-field values from about 0 A/m to about 100 A/m when said excitation signal has a frequency of 1kHz.
48. The method of claim 43, wherein a relative permeability of said core is greater than or equal to 300 when said excitation signal has a frequency of 13.56MHz.
49. The method of claim 43, wherein a relative permeability of said core is greater than or equal to 300 when said excitation signal has a frequency from 8.2MHz to 13.56MHz.
50. The method of claim 43, wherein said core has a length in a range from 20 to 80 cm and a cross-sectional area in a range from 0.02 to 1 cm2.
51. The method of claim 50, wherein a relative permeability of said core is greater than 5000 for associated H-field values from about 0 A/m to about 100 A/m when said excitation signal has a frequency of 1kHz.
52. The method of claim 50, wherein a relative permeability of said core is greater than or equal to 300 when said excitation signal has a frequency of 13.56MHz.
53. The method of claim 50, wherein a relative permeability of said core is greater than or equal to 300 when said excitation signal has a frequency from 8.2MHz to 13.56MHz.
54. The method of claim 43, said antenna comprising a plurality of said coil windings.
55. The method of claim 54, wherein a first one of said coil windings is inductively coupled to a second one of said coil windings.
56. The method of claim 54, wherein first and second ones of said coil windings are configured for operation at different associated frequencies.
57. The method of claim 56, wherein said first coil winding is configured for transmitting at a first frequency and said second coil winding is configured for receiving a response from an EAS or RFID tag at a second frequency different from said first frequency.
58. The method of claim 43, wherein said excitation signal has a frequency in a range from 9KHz to 300MHz.
59. The method of claim 43, wherein said nanocrystalline magnetic material comprises grains having a maximum dimension of in a range from 10nm to 40nm.
60. The method of claim 43, wherein said nanocrystalline magnetic material is an alloy comprising FeCuNbSiB.
61. The method of claim 43, wherein said nanocrystalline magnetic material is an alloy comprising FeZrNbCu.
62. The method of claim 43, wherein said nanocrystalline magnetic material is an alloy comprising FeCoZrBCu.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US10/745,128 US7154447B2 (en) | 2003-12-22 | 2003-12-22 | Nanocrystalline core antenna for EAS and RFID applications |
| US10/745,128 | 2003-12-22 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2491256A1 true CA2491256A1 (en) | 2005-06-22 |
Family
ID=34552866
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002491256A Abandoned CA2491256A1 (en) | 2003-12-22 | 2004-12-21 | Nanocrystalline core antenna for eas and rfid applications |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US7154447B2 (en) |
| EP (1) | EP1548876A3 (en) |
| KR (1) | KR20050063706A (en) |
| CN (1) | CN1638191A (en) |
| CA (1) | CA2491256A1 (en) |
| IL (1) | IL165324A0 (en) |
Families Citing this family (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6924781B1 (en) | 1998-09-11 | 2005-08-02 | Visible Tech-Knowledgy, Inc. | Smart electronic label employing electronic ink |
| WO2005024595A2 (en) | 2003-09-03 | 2005-03-17 | Visible Tech-Knowledgy, Inc. | Electronically updateable label and display |
| GB0323349D0 (en) * | 2003-10-06 | 2003-11-05 | Linksure Ltd | Verification means |
| US7541755B2 (en) * | 2005-10-11 | 2009-06-02 | Universities Research Association, Inc. | Inductive load broadband RF system |
| KR100822850B1 (en) * | 2006-12-06 | 2008-04-17 | 한국타이어 주식회사 | Rfid tag for tire having flexibility and conductivity |
| CN101231707A (en) * | 2007-01-25 | 2008-07-30 | 3M创新有限公司 | Electromagnetic shielding device |
| US7832952B2 (en) | 2007-03-21 | 2010-11-16 | Avery Dennison Corporation | High-frequency RFID printer |
| KR100917870B1 (en) * | 2007-07-23 | 2009-09-16 | 주식회사 티인티 | Method of preparing rfid tag and rfid tag |
| JP4962190B2 (en) * | 2007-07-27 | 2012-06-27 | パナソニック株式会社 | ANTENNA DEVICE AND WIRELESS COMMUNICATION DEVICE |
| US8234507B2 (en) | 2009-01-13 | 2012-07-31 | Metrologic Instruments, Inc. | Electronic-ink display device employing a power switching mechanism automatically responsive to predefined states of device configuration |
| US8457013B2 (en) | 2009-01-13 | 2013-06-04 | Metrologic Instruments, Inc. | Wireless dual-function network device dynamically switching and reconfiguring from a wireless network router state of operation into a wireless network coordinator state of operation in a wireless communication network |
| US8730120B2 (en) * | 2010-11-12 | 2014-05-20 | Panasonic Corporation | Transmission/reception antenna and transmission/reception device using same |
| US8683707B1 (en) | 2012-03-28 | 2014-04-01 | Mike Alexander Horton | Magnetically modulated location system |
| US9800134B2 (en) * | 2015-02-25 | 2017-10-24 | Rockwell Automation Technologies, Inc. | Motor drive with LCL filter inductor with built-in passive damping resistor for AFE rectifier |
| RU2724586C1 (en) * | 2019-11-19 | 2020-06-25 | Общество с ограниченной ответственностью "Ляско Радиоэлектронные Технологии" | Magnetic-dielectric dipole |
Family Cites Families (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US117282A (en) * | 1871-07-25 | Improvement in adjustable reflectors for lamps | ||
| AT375215B (en) * | 1981-08-21 | 1984-07-10 | Motronic Elektro Geraete | FERRITE ANTENNA |
| JPH02223205A (en) * | 1988-11-02 | 1990-09-05 | Kurieiteitsuku Japan:Kk | Antenna |
| JP3891448B2 (en) * | 1994-04-11 | 2007-03-14 | 日立金属株式会社 | Thin antenna and card using the same |
| SE521232C2 (en) | 1997-02-17 | 2003-10-14 | Rso Corp | Sensor and method for contactless detection of objects |
| SE515182C2 (en) | 1998-06-18 | 2001-06-25 | Rso Corp | Method and system for remote detection of objects |
| US6840440B2 (en) * | 1998-11-11 | 2005-01-11 | Mitsubishi Materials Corporation | Identifying system of overlapped tag |
| US6121879A (en) | 1998-12-23 | 2000-09-19 | Sensormatic Electronics Corporation | Deactivation element configuration for microwave-magnetic EAS marker |
| JP3855253B2 (en) * | 2000-06-13 | 2006-12-06 | アイシン精機株式会社 | Bar antenna and manufacturing method thereof |
| DE10128004A1 (en) * | 2001-06-08 | 2002-12-19 | Vacuumschmelze Gmbh | Wound inductive device has soft magnetic core of ferromagnetic powder composite of amorphous or nanocrystalline ferromagnetic alloy powder, ferromagnetic dielectric powder and polymer |
| US7978078B2 (en) | 2001-12-21 | 2011-07-12 | Sensormatic Electronics, LLC | Magnetic core transceiver for electronic article surveillance marker detection |
| JP2003283231A (en) * | 2002-03-26 | 2003-10-03 | Aisin Seiki Co Ltd | Antenna and manufacturing method therefor |
| EP1420476B1 (en) * | 2002-11-13 | 2008-02-06 | Mitsubishi Materials Corporation | Wrist watch containing internal tag, radio watch, and antenna for wrist watch |
| DE10302646B4 (en) * | 2003-01-23 | 2010-05-20 | Vacuumschmelze Gmbh & Co. Kg | Antenna core and method of manufacturing an antenna core |
| US6960912B2 (en) * | 2003-05-12 | 2005-11-01 | Vacuumschmelze Gmbh & Co. Kg | Magnetic field sensor device |
-
2003
- 2003-12-22 US US10/745,128 patent/US7154447B2/en active Active
-
2004
- 2004-11-22 IL IL16532404A patent/IL165324A0/en unknown
- 2004-12-01 EP EP04028430A patent/EP1548876A3/en not_active Ceased
- 2004-12-21 CA CA002491256A patent/CA2491256A1/en not_active Abandoned
- 2004-12-21 KR KR1020040109246A patent/KR20050063706A/en not_active Application Discontinuation
- 2004-12-22 CN CNA2004101046189A patent/CN1638191A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| CN1638191A (en) | 2005-07-13 |
| US20050134515A1 (en) | 2005-06-23 |
| EP1548876A2 (en) | 2005-06-29 |
| IL165324A0 (en) | 2006-01-15 |
| KR20050063706A (en) | 2005-06-28 |
| US7154447B2 (en) | 2006-12-26 |
| EP1548876A3 (en) | 2006-01-25 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US7317426B2 (en) | Core antenna for EAS and RFID applications | |
| US7978078B2 (en) | Magnetic core transceiver for electronic article surveillance marker detection | |
| US7154447B2 (en) | Nanocrystalline core antenna for EAS and RFID applications | |
| US5912622A (en) | Anti-theft tag | |
| US6535108B1 (en) | Modulation of the resonant frequency of a circuit using an energy field | |
| US6130612A (en) | Antenna for RF tag with a magnetoelastic resonant core | |
| EP0215605B1 (en) | Rf reactivatable marker | |
| US7804411B2 (en) | Combination EAS and RFID label or tag using a hybrid RFID antenna | |
| US7812729B2 (en) | Combination EAS and RFID label or tag with controllable read range using a hybrid RFID antenna | |
| US6840440B2 (en) | Identifying system of overlapped tag | |
| US7804410B2 (en) | Combination EAS and RFID label or tag | |
| EP1489635B1 (en) | A magnetic core antenna | |
| US7123129B1 (en) | Modulation of the resonant frequency of a circuit using an energy field | |
| EP1120733A1 (en) | Apparatus for identifying article | |
| JP3476000B2 (en) | Identification method of superimposed tags | |
| JP3399505B2 (en) | Identification device for articles in metal case | |
| US9711019B2 (en) | Marker with a bone shaped magnetic core | |
| JP3255222B2 (en) | Tags to prevent theft | |
| KR200247071Y1 (en) | structure of sensor for article surveillance system | |
| KR100242265B1 (en) | Novel thrombin inhibitors having arylalkylsulfonyl group |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |