Antenna for a Combination Eas/Rfid Tag with a Detacher

• US 20070262865A1
• Filed: 11/02/2005
• Published: 11/15/2007
• Est. Priority Date: 11/02/2004
• Status: Active Grant

• Current Assignee: Sensormatic Electronics LLC (Johnson Controls International plc)
• Original Assignee: Sensormatic Electronics Corporation (Johnson Controls International plc)
• Inventors: Copeland, Richard, Shafer, Gary
• Granted Patent: US 7,701,343 B2
• Time in Patent Office: Days
• US Class Current: 340/572.700
• CPC Class Codes: G06K 19/07749 the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
• CPC Class Codes: H01Q 1/22 by structural association with other equipment or articles
• CPC Class Codes: H01Q 1/38 formed by a conductive layer on an insulating support patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142
• CPC Class Codes: H01Q 9/065 Microstrip dipole antennas patch antenna H01Q9/0407
• CPC Class Codes: Y10T 24/50 Readily interlocking, two-part fastener requiring either destructive or tool disengagement
• CPC Class Codes: Y10T 24/505 including additional fastener structure linking parts
• CPC Class Codes: Y10T 70/5004 For antitheft signaling device on protected article

Abstract

A security device detaches a combination electronic article surveillance (EAS) and radio frequency identification (RFID) tag (EAS/RFID tag), and includes a detacher (magnet) to selectively disengage a clutch release disposed in a first portion of the combination EAS/RFID tag, a near field circular microstrip antenna configured to electronically read information stored in a second portion of the combination EAS/RFID tag. The antenna encircles the detacher and reads information from the second portion of the combination EAS/RFID tag at a position relative to the detacher when the second portion of the tag is disposed at any angle relative to the detacher and only when the detacher is positioned to disengage the clutch release. As long as the portion of the EAS/RFID tag containing the clutch end mechanism is located over the detaching magnet, the RFID label is in a valid detection zone regardless of its orientation relative to the antenna.

Claims

1. A security device for detaching a combination electronic article surveillance (EAS) and radio frequency identification (RFID) tag (EAS/RFID tag), said security device comprising:

a detacher configured to selectively disengage a clutch release disposed in a first portion of the combination EAS/RFID tag; and

a near field substantially circular microstrip antenna configured to electronically read information stored in a second portion of the combination EAS/RFID tag, said near field antenna configured to substantially encircle said detacher and configured to read information from said second portion of the combination EAS/RFID tag at a position relative to said detacher when said second portion of said tag is disposed at any angle relative to said detacher.

2. A security device according to claim 1, wherein the near field antenna is configured to read information only when said detacher is positioned to disengage the clutch release in the first portion of the combination EAS/RFID tag.

3. A security device according to claim 1, wherein the detacher magnetically disengages the clutch release.

4. A security device according to claim 3, wherein the near field antenna is configured to only read information when said detacher is positioned to disengage the clutch release in the first portion of the combination EAS/RFID tag.

5. A security device according to claim 1, wherein the security device further comprises:

a substrate, the substrate having a first surface and a second surface;

a feed port mounted on the substrate;

a terminating resistor mounted on the substrate; and

a ground plane,

wherein the circular antenna microstrip is mounted on the first surface of the substrate and the second surface of the substrate is mounted on the ground plane, and

wherein the feed port is coupled to a first portion of the antenna and the terminating resistor is coupled to a second portion of the antenna and to the ground plane.

6. A security device according to claim 5 wherein the substantially circular microstrip has a diameter ranging from about c/{2π

f(ε

_r)^1/2} to about c/{π

f(ε

_r)^1/2}, where c is the speed of light (3×

10⁸ meters/second), f is the operating frequency (cycles/second), and ε

_r is the relative permittivity of the substrate.

7. A security device according to claim 6, wherein the feed port is excited by one of a monopole and a dipole feed excitation signal.

8. A security device according to claim 1, wherein the second portion of the combination EAS/RFID tag includes an RFID element and the RFID element resides substantially outside of the perimeter of the circular microstrip antenna.

9. A security device for detaching combination electronic article surveillance (EAS) and radio frequency identification (RFID) tags (EAS/RFID tags), said security device comprising:

a detacher having an axis defined therethrough, said detacher configured to selectively disengage a clutch release disposed in a first portion of the combination EAS/RFID tag;

a substantially circular-shaped monopole microstrip near field antenna configured to electronically read information stored in a second portion of the combination EAS/RFID tag, said near field antenna configured to substantially encircle said detacher and configured to read information from said second portion of the combination EAS/RFID tag when said combination EAS/RFID tag is positioned at any angle relative to said axis.

10. A security device according to claim 9, wherein the near field antenna is configured to only read information when said detacher is positioned to disengage the clutch release in the first portion of the combination EAS/RFID tag.

11. A security device according to claim 9, wherein the detacher magnetically disengages the clutch release.

12. A security device according to claim 11, wherein the near field antenna is configured to read information only when said detacher is positioned to disengage the clutch release in the first portion of the combination EAS/RFID tag.

13. A security device according to claim 9, wherein the security device further comprises:

a substrate, the substrate having a first surface and a second surface;

a feed port mounted on the substrate;

a terminating resistor mounted on the substrate; and

a ground plane,

wherein

the circular antenna microstrip is mounted on the first surface of the substrate and the second surface of the substrate is mounted on the ground plane, and

the feed port is coupled to a first portion of the antenna and the terminating resistor is coupled to a second portion of the antenna and to the ground plane.

14. An antenna for use with a combination electronic article surveillance (EAS) and radiofrequency identification (RFID) tag, the antenna comprising

a substrate;

and

a substantially circular microstrip mounted on the substrate.

15. An antenna according to claim 14, the antenna further comprising:

a detacher magnet having a substantially circular perimeter, the substantially circular microstrip being mounted on the substrate around the perimeter of the detacher magnet.

16. An antenna according to claim 14, wherein the substrate comprises first and second surfaces, the substantially circular microstrip being mounted on the first surface of the substrate, and wherein the antenna further comprises

a detacher magnet having a substantially circular perimeter, the detacher magnet being disposed in proximity to the second surface of the substrate such that the substantially circular microstrip is disposed outside the perimeter of the detacher magnet.

17. An antenna according to claim 14, wherein the antenna further comprises:

a feed port mounted on the substrate; and

a terminating resistor mounted on the substrate, wherein

the feed port is coupled to a first portion of the antenna and the terminating resistor is coupled to a second portion of the antenna.

18. An antenna according to claim 17, wherein the substrate comprises first and second surfaces, wherein the antenna further comprises:

a ground plane, and

wherein the circular antenna microstrip is mounted on the first surface of the substrate and the second surface of the substrate is mounted on the ground plane, and

the feed port is coupled to a first portion of the antenna and the terminating resistor is coupled to a second portion of the antenna and to the ground plane.

19. An antenna according to claim 17, wherein the feed port is excited by one of a monopole and dipole feed excitation signal.

20. An antenna according to claim 14, wherein the substantially circular microstrip has a diameter ranging from about c/{2π

f(ε

_r)^1/2} to about c/{π

f(ε

_r)^1/2}, where c is the speed of light (3×

10⁸ meters/second), f is the operating frequency (cycles/second), and ε

_r is the relative permittivity of the substrate.