Arrangement for, and method of, detecting passage of objects associated with radio frequency (RF) identification (RFID) object tags through a portal

• US 10,061,952 B2
• Filed: 12/20/2016
• Issued: 08/28/2018
• Est. Priority Date: 12/20/2016
• Status: Active Grant

• Current Assignee: Symbol Technologies, LLC (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, LLC (Zebra Technologies Corporation)
• Inventors: Duron, Mark W., Strat, Daniella, Austin, Timothy B., Bellows, David
• Primary Examiner(s): Zimmerman, Brian
• Assistant Examiner(s): TRAN, THANG DUC
• Application Number:
  US15/384,475
• Publication Number:
  US 20180173912A1
• Time in Patent Office: 616 Days
• Field of Search: 3405721-5729, 340 101- 106
• CPC Class Codes: G06K 7/10425 the interrogation device being arranged for interrogation of record carriers passing by the interrogation device

Abstract

A radio frequency (RF) identification (RFID) reader is mounted in a venue in proximity to a portal that is openable and closable by a door. The portal reader reads RFID object tags associated with objects that approach the portal. An electrical conductor is associated, and jointly movable, with the door. A portal RFID tag is mounted at the portal. The portal tag is overlain by the electrical conductor in a closed door position and is remote from the electrical conductor in an open door position. The portal tag is readable by the portal reader in either the open or the closed door position. A controller identifies any objects that have passed through the portal based on whether the object tags have been read, as well as whether the portal tag has been read in either the open or the closed door position.

Claims

1. An arrangement for detecting passage of objects associated with radio frequency (RF) identification (RFID) object tags through a portal that is openable and closable by a door movable between respective open and closed positions at a venue, the arrangement comprising:

a portal RFID reader mounted in the venue in proximity to the door for reading the RFID object tags that approach the portal;

an electrical conductor associated, and jointly movable, with the door;

a portal device mounted at the portal and having a portal RFID tag, the portal tag being overlain by the electrical conductor in the closed position of the door and being remote from the electrical conductor in the open position of the door, the portal tag being readable by the portal reader in one of the open and closed positions of the door; and

a controller operatively connected to the portal reader, and operative for identifying the objects that have passed through the portal based on whether the object tags have been read, as well as whether the portal tag has been read in one of the open and closed positions of the door wherein the portal tag includes a dipole antenna having a pair of spaced-apart antenna elements, wherein the electrical conductor includes at least one of (i) an inductive shunt for inductively shunting the antenna elements to enable the portal tag to be read in the closed position of the door, and wherein the portal tag is prevented from being read by the portal reader in the open position of the door and (ii) a pair of capacitive shunts for capacitively shunting each antenna element to enable the portal tag to be read in the closed position of the door, and wherein the portal tag is prevented from being read by the portal reader in the open position of the door.

2. The arrangement of claim 1, wherein the door is constituted of an electrically conductive material, and wherein the electrical conductor is constituted of the electrically conductive material of the door.

3. The arrangement of claim 1, wherein the electrical conductor is an electrically conductive plate mounted on the door.

4. The arrangement of claim 1, wherein the portal tag is read by the portal reader in the open position of the door.

5. The arrangement of claim 1, wherein the portal device includes a support on which the portal tag is mounted, and wherein the support is constituted of a resilient material for resiliently bearing against the door in the closed position.

6. The arrangement of claim 1, wherein the portal device includes a tamper tag that is readable by the portal reader in each position of the door, and wherein the controller determines that the portal device has been tampered with when the tamper tag is no longer being read.

7. The arrangement of claim 6, wherein the tamper tag includes a dipole antenna having a pair of spaced-apart antenna elements, and a tamper wire connected between the antenna elements as an impedance transformer, and wherein the controller detects that the portal reader has not read the tamper tag due to an impedance mismatch upon disturbance of the tamper wire.

8. The arrangement of claim 7, wherein the portal device includes a support on which the tamper tag is mounted, and wherein the support includes a tear line extending across the tamper wire.

9. A method of detecting passage of objects associated with radio frequency (RF) identification (RFID) object tags through a portal that is openable and closable by a door movable between respective open and closed positions at a venue, the method comprising:

reading the RFID object tags that approach the portal with a portal RFID reader mounted in the venue in proximity to the door;

associating an electrical conductor with the door for joint movement therewith;

mounting a portal device having a portal RFID tag at the portal in a location in which the portal tag is overlain by the electrical conductor in the closed position of the door and is remote from the electrical conductor in the open position of the door, the portal tag being readable by the portal reader in one of the open and closed positions of the door; and

identifying the objects that have passed through the portal based on whether the object tags have been read, as well as whether the portal tag has been read in one of the open and closed positions of the door and configuring the portal tag with a dipole antenna having a pair of spaced-apart antenna elements, and at least one of (i) inductively shunting the antenna elements with an inductive shunt to enable the portal tag to be read in the closed position of the door, and preventing the portal tag from being read by the portal reader in the open position of the door and (ii) capacitively shunting each antenna element with a pair of capacitive shunts to enable the portal tag to be read in the closed position of the door, and preventing the portal tag from being read by the portal reader in the open position of the door.

10. The method of claim 9, and constituting the door of an electrically conductive material, and constituting the electrical conductor of the electrically conductive material of the door.

11. The method of claim 9, and configuring the electrical conductor as an electrically conductive plate, and mounting the plate on the door.

12. The method of claim 9, and enabling the portal tag to be read by the portal reader in the open position of the door.

13. The method of claim 9, and configuring the portal device with a support on which the portal tag is mounted, and constituting the support of a resilient material for resiliently bearing against the door in the closed position.

14. The method of claim 9, and configuring the portal device with a tamper tag that is readable by the portal reader in each position of the door, and determining that the portal device has been tampered with when the tamper tag is no longer being read.

15. The method of claim 14, and configuring the tamper tag with a dipole antenna having a pair of spaced-apart antenna elements, and connecting a tamper wire between the antenna elements as an impedance transformer, and wherein the determining is performed by detecting an impedance mismatch upon disturbance of the tamper wire.

16. The method of claim 15, and configuring the portal device with a support on which the tamper tag is mounted, and extending a tear line across the tamper wire.