RFID system

• US 8,816,857 B2
• Filed: 10/19/2011
• Issued: 08/26/2014
• Est. Priority Date: 10/20/2010
• Status: Active Grant

• Current Assignee: Panduit Corporation
• Original Assignee: Panduit Corporation
• Inventors: Nordin, Ronald A., Bolouri-Saransar, Masud
• Primary Examiner(s): MCNALLY, KERRI L
• Application Number:
  US13/276,505
• Publication Number:
  US 20120098664A1
• Time in Patent Office: 1,042 Days
• Field of Search: 340/572.1
• 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 a ferrite element to an RFID tag;

attaching the 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;

placing a ferrite member in proximity to the antenna system and distal relative to the RFID tag;

determining a safe operating region for 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, and further in response to the ferrite element, said step of shaping the magnetic field in response to the ferrite element being responsive to a distance between adjacent ones of equipment installed on the rack.

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 further responsive to a distance between the ferrite element and the antenna system.

5. The method of claim 1, wherein said step of shaping the magnetic field is further responsive to a material characteristic of the ferrite member.

6. The method of claim 1, wherein said step of shaping the magnetic field is further responsive to a dimensional characteristic of the ferrite member.

7. The method of claim 1, wherein said step of determining a safe operating region for the RFID tag is responsive to at least one of (i) a dimensional characteristic of a PCB trace, (ii) a dimensional characteristic of a ferrite core installed on the RFID tag, (iii) a distance between the RFID tag and a metal surface in the vicinity of the RFID tag, and (iv) a transmission power magnitude of the antenna system.

8. 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.

9. 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;

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

attaching a ferrite element to the RFID tag; and

shaping the magnetic field in response to the ferrite element, 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.

10. The method of claim 9, wherein said step of determining a safe operating region for the RFID tag is responsive to at least one of (i) a dimensional characteristic of a PCB trace, (ii) a dimensional characteristic of a ferrite core installed on the RFID tag, (iii) a distance between the RFID tag and a metal surface in the vicinity of the RFID tag, and (iv) a transmission power magnitude of the antenna system.

11. The method of claim 9, 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.

12. The method of claim 9, wherein said step of attaching an antenna system to the rack is performed on a mounting post of the rack.

13. The method of claim 12, 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.