Magnetic core transceiver for electronic article surveillance marker detection

• US 7,978,078 B2
• Filed: 12/21/2001
• Issued: 07/12/2011
• Est. Priority Date: 12/21/2001
• Status: Active Grant

• Current Assignee: Sensormatic Electronics LLC (Johnson Controls International plc)
• Original Assignee: Sensormatic Electronics LLC (Johnson Controls International plc)
• Inventors: Copeland, Richard L., Embling, Steven W., Farrell, William M., Balch, Brent F., Hall, Stewart E.
• Primary Examiner(s): Lee; Benjamin C
• Application Number:
  US10/037,337
• Publication Number:
  US 20030117282A1
• Time in Patent Office: 3,490 Days
• Field of Search: 340/572.7, 340/572.1, 343/718, 343/788, 343/787, 343/741, 342/44, 342/42, 324/243, 728/692.1, 728/379, 728/689
• US Class Current: 340/572.7
• CPC Class Codes: G08B 13/2402 Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting mechanical aspects of the tags, e.g. related to locking E05B73/0017; RFID readers G06K7/00; RFID tags G06K19/00; access control systems G07C9/00; anti-theft control in point of sale systems G07G3/003; security seals G09F3/03
• CPC Class Codes: H01Q 7/08 Ferrite rod or like elongated core
• CPC Class Codes: Y10T 428/294 including metal or compound thereof [excluding glass, ceramic and asbestos]
• CPC Class Codes: Y10T 428/32 Composite [nonstructural laminate] of inorganic material having metal-compound-containing layer and having defined magnetic layer

Abstract

A magnetic core transceiver antenna for EAS marker detection is provided. The core includes a stack of amorphous alloy ribbons insulated from each other and laminated together. A coil winding of wire, also insulted from the ribbons, and connected to an electronic controller provides the transmitter and receiver modes. The transceiver antenna is optimized for the dual mode operation, and is smaller and uses less power than conventional air-core EAS antennas with equivalent performance. Complex core geometries, such as a sandwiched stack of different sized ribbons, can be implemented to vary the effective permeability of the core to customize antenna performance. Multiple transceiver antennas can be combined to increase the size of the generated EAS interrogation zone.

Claims

1. An electronic article surveillance antenna for generating an electromagnetic field to interrogate and detect electronic surveillance markers, comprising:

a core formed by a plurality of amorphous alloy ribbons insulated from each other and stacked to form a substantially elongated solid rectangular shape; and

a coil winding of wire disposed around at least a portion of said core, said coil winding of wire insulated from said core, said core and said coil winding being of a minimum size for generation of an electromagnetic field for interrogation and detection of electronic article surveillance markers;

wherein said core includes a central member about 50 centimeters long and about 2 centimeters wide comprised of about 25 amorphous alloy ribbons, each amorphous alloy ribbon about 23 microns thick stacked and laminated together forming said central core member, and a first outer member and a second outer member disposed on opposite sides of said central member, each of said first outer member and said second outer member about 30 centimeters long and 2 centimeters wide comprised of about 15 amorphous alloy ribbons, each amorphous alloy ribbon about 23 microns thick stacked and laminated together forming said first outer layer and said second outer layer, respectively, said central core member and said first and said second outer members together form said core.

2. An electronic article surveillance system for generating an electromagnetic field to interrogate and detect electronic surveillance markers, comprising:

a core including a plurality of amorphous alloy ribbons insulated from each other and stacked to form an elongate solid rectangular shape; and

a coil winding of wire disposed around at least a portion of said core, said coil winding of wire insulated from said core, said core and said coil winding being configured for generating an electromagnetic field for interrogation and detection of electronic article surveillance markers, wherein said core comprises a central member disposed between a first outer member and a second outer member, wherein at least a portion of said central member extends beyond an end portion of one of said first and second outer members.

3. The system of claim 2, wherein said first outer member has a first length, said second outer member has a second length, said first length substantially equal to said second length.

4. The system of claim 3, wherein said central member has a third length, said third length greater than said first length and said second length.

5. The system of claim 4, wherein said first length and said second length are about 30 centimeters and said third length is about 50 centimeters.

6. An antenna for use in an electronic article surveillance system, said antenna comprising:

a core comprising a central member disposed between a first outer member and a second outer member, wherein at least a portion of said central member extends beyond an end portion of one of said first and second outer members; and

a coil winding disposed around at least a portion of said core.

7. The antenna of claim 6, wherein said first outer member has a first length, said second outer member has a second length, said first length substantially equal to said second length.

8. The antenna of claim 7, wherein said central member has a third length, said third length greater than said first length and said second length.

9. The antenna of claim 8, wherein said first length and said second length are about 30 centimeters and said third length is about 50 centimeters.

10. A system for generating an electromagnetic field to interrogate and detect electronic article surveillance markers, comprising:

a plurality of electronic article surveillance antennas, each of said plurality of antennas including;

a core formed by a plurality of amorphous alloy ribbons insulated from each other and stacked to form an elongate solid rectangular shape having first and second ends; and

a coil winding of wire disposed around at least a portion of said core, said coil winding of wire insulated from said core, said core and said coil winding being of at least a minimum size for operably generating an electromagnetic field for interrogation and detection of electronic article surveillance markers; and

,

at least one electronic controller connected to said plurality of antennas, said electronic controller including;

transmitter means for generating an electromagnetic field for transmission into an interrogation zone for reception by an electronic article surveillance marker, the electronic article surveillance marker responding with a characteristic response signal;

receiver means for detecting the characteristic response signal from the electronic article surveillance marker; and

,

switching means for switching said coil winding of wire between said transmitter means and said receiver means;

wherein a Q value of at least one of said antennas is less than or equal to about 20 at an EAS operating frequency.