RFID System

• US 20120098664A1
• Filed: 10/19/2011
• Published: 04/26/2012
• Est. Priority Date: 10/20/2010
• Status: Active Grant

• Current Assignee: Panduit Corporation
• Original Assignee: Panduit Corporation
• Inventors: Nordin, Ronald A., Bolouri-Saransar, Masud
• Granted Patent: US 8,816,857 B2
• Time in Patent Office: Days
• US Class Current: 340/572.1
• 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: G06K 19/07771 the record carrier comprising means for minimising adverse effects on the data communication capability of the record carrier, e.g. minimising Eddy currents induced in a proximate metal or otherwise electromagnetically interfering object
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: G06K 7/10168 the powering being adversely affected by environmental influences, e.g. unwanted energy loss in the interrogation signal due to metallic or capacitive objects in the proximity of the interrogation device or in the proximity of the interrogated record carrier
• CPC Class Codes: G06K 7/10336 the antenna being of the near field type, inductive coil
• CPC Class Codes: G06K 7/10356 using a plurality of antennas, e.g. configurations including means to resolve interference between the plurality of antennas
• CPC Class Codes: G06Q 10/087 Inventory or stock management, e.g. order filling, procurement or balancing against orders

Abstract

The present invention provides an automated system for asset tracking and management and utilizes near field Radio Frequency IDentification (RFID) technology. RFID tags are attached to the assets, and RFID antennas (and corresponding readers) are strategically located in close proximity to read the tags. As applied to a rack or cabinet, near-field antennas are mounted along one of the mounting posts at each rack unit location such that when a piece of equipment (rack mounted or rail mounted) is installed at a particular rack unit space, the tag will be read and registered in an RFID management system. A magnetic field shaping arrangement ensures that crosstalk between adjacent rack positions is prevented. Ferrite elements are used to control the magnetic field.

Claims

1. A method of tracking equipment installed on a rack, the method comprising the steps of:

attaching an RFID tag to a mounting portion of the equipment;

attaching an antenna system to the rack, the antenna system issuing a magnetic field that impinges upon the RFID tag; and

shaping the magnetic field issued by the antenna system in response to a distance between the antenna system and the RFID tag.

2. The method of claim 1, wherein said step of attaching an antenna system to the rack is performed on a mounting post of the rack.

3. The method of claim 2, wherein said step of attaching an RFID tag is performed on a mounting ear of the equipment in close proximity of the mounting post of the rack.

4. The method of claim 1, wherein said step of shaping the magnetic field is responsive to a distance between the RFID tag and the antenna system.

5. The method of claim 1, wherein there is further provided the step of attaching a ferrite element to the RFID tag.

6. The method of claim 5, wherein said step of shaping the magnetic field is responsive to a distance between the ferrite element and the antenna system.

7. The method of claim 1, wherein there is further provided the step of placing a ferrite member in proximity to the antenna system and distal relative to the RFID tag.

8. The method of claim 7, wherein said step of shaping the magnetic field is responsive to a material characteristic of the ferrite member.

9. The method of claim 7, wherein said step of shaping the magnetic field is responsive to a dimensional characteristic of the ferrite member.

10. The method of claim 1, wherein there are further provided the steps of:

attaching a ferrite element to the RFID tag; and

shaping the magnetic field in response to the ferrite element.

11. The method of claim 10, wherein said step of shaping the magnetic field in response to the ferrite element is responsive to a distance between adjacent ones of equipment installed on the rack, and there is provided the further step of determining a safe operating region for the RFID tag.

12. The method of claim 11, wherein said step of determining a safe operating region for the RFID tag is responsive to a dimensional characteristic of a PCB trace.

13. The method of claim 11, wherein said step of determining a safe operating region for the RFID tag is responsive to a dimensional characteristic of a ferrite core installed on the RFID tag.

14. The method of claim 11, wherein said step of determining a safe operating region for the RFID tag is responsive to a distance between the RFID tag and a metal surface in the vicinity of the RFID tag.

15. The method of claim 11, wherein said step of determining a safe operating region for the RFID tag is responsive to a transmission power magnitude of the antenna system.

16. The method of claim 1, wherein the RFID tag has a near field antenna element having a determinable antenna impedance characteristic, and an integrated circuit having a determinable integrated circuit input impedance characteristic, and there is provided the further step of configuring the determinable antenna impedance characteristic and the determinable integrated circuit input impedance characteristic to be substantially equal to one another to achieve enhanced power transfer therebetween.

17. A system for tracking equipment that is installed on a rack, the system comprising:

a near field RFID tag installed in a mounting portion of the equipment that is to be tracked;

an antenna array installed on the rack in predetermined relation to the near field RFID tag for emitting a magnetic field; and

a magnetic field shaping arrangement for controlling the magnetic field issued by said antenna array.

18. The system of claim 17, wherein said magnetic field shaping arrangement comprises a ferrite element installed on said near field RFID tag.

19. The system of claim 17, wherein said magnetic field shaping arrangement comprises a ferrite member installed in the vicinity of said antenna array distal from said near field RFID tag.

20. The system of claim 17, wherein there is further provided a fastener for attaching the equipment to the rack, said fastener affixing said near field RFID tag to the mounting portion of the equipment that is to be protected.