HIGH-Q AND OVER-COUPLED NEAR-FIELD RFID READER ANTENNA FOR IMPROVED TAG READ RANGE

• US 20170323501A1
• Filed: 05/03/2017
• Published: 11/09/2017
• Est. Priority Date: 10/31/2015
• Status: Active Grant

• Current Assignee: Disney Enterprises Incorporated (The Walt Disney Company)
• Original Assignee: Disney Enterprises Incorporated (The Walt Disney Company)
• Inventors: SAMPLE, ALANSON
• Granted Patent: US 10,223,850 B2
• Time in Patent Office: Days
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• CPC Class Codes: G06K 19/07762 the adhering arrangement making the record carrier wearable, e.g. having the form of a ring, watch, glove or bracelet record carriers for insertion in the human body for medical purposes A61B90/00; record carriers adapted for attachment to animals A01K11/00
• CPC Class Codes: G06K 7/10148 the step consisting of dynamically tuning the resonant circuit of the interrogation device that is emitting the interrogation signal, e.g. for impedance matching inside of the interrogation device for tuning related to loop aerials in general H01Q7/00
• CPC Class Codes: G06K 7/10366 the interrogation device being adapted for miscellaneous applications
• CPC Class Codes: G06K 7/10415 the interrogation device being fixed in its position, such as an access control device for reading wireless access cards, or a wireless ATM banking machines in general G07F19/00
• CPC Class Codes: G07C 2009/00793 by Hertzian waves
• CPC Class Codes: G07C 9/00309 operated with bidirectional data transmission between data carrier and locks
• CPC Class Codes: G07C 9/00904 for hotels, motels, office buildings or the like
• CPC Class Codes: G07C 9/28 the pass enabling tracking or indicating presence
• CPC Class Codes: H04B 5/72 for local intradevice communication

Abstract

An RFID system in which at least one of the RFID tag antenna and the RFID reader antenna has an impedance matching network associated therewith in order to better match the impedances of the two antennas. This impedance matching places the antennas into an over-coupled regime once they are within a reasonable distance of each other (e.g., 2 to 50 mm). It also increases the Q-factor of the improved antenna, which can greatly increase the range at which the RFID reader can read the RFID tag. This improved RFID system may be used in any of a variety of application, including operating a door lock mechanism.

Claims

1. An RFID system, comprising:

a tag including an antenna that selectively transfers a data signal; and

a reader including an antenna that receives the data signal from the tag;

wherein at least one of the tag antenna and the reader antenna have a Q-factor that is greater than 30;

wherein the tag antenna and the reader antenna are sufficiently matched in impedance to place the two antennas into an over-coupled regime.

2. An RFID system as defined in claim 1, wherein the tag is worn by a user.

3. An RFID system as defined in claim 1, wherein the tag is attached to a wristband worn by a user.

4. An RFID system as defined in claim 1, wherein the reader is attached to a door having a door lock mechanism and provides an unlock signal to the door lock mechanism.

5. An RFID system as defined in claim 1, wherein the tag is attached to a wristband worn by a user and the reader is attached to a door having a door lock mechanism and provides an unlock signal to the door lock mechanism.

6. An RFID system as defined in claim 5, wherein the door includes a generally planar door surface and a door latch actuator that pivots about a pivot axis, the door latch actuator including an elongated handle portion defining a handle axis that extends generally transversely from the pivot axis and generally parallel to the planar door surface, the reader being located in relation to the planar door surface in a position vertically offset from and spaced apart from the handle axis and horizontally offset from and spaced apart from the pivot axis.

7. An RFID system as defined in claim 1, wherein the two antennas are in an over-coupled regime when they are located within 30 mm of each other.

8. An RFID system as defined in claim 1, wherein the two antennas are in an over-coupled regime when they are located within 20 mm of each other.

9. An RFID system as defined in claim 1, wherein the two antennas are in an over-coupled regime when they are located within 10 mm of each other.

10. An RFID system as defined in claim 1, wherein the reader antenna includes an impedance matching network associated therewith.

11. An RFID system as defined in claim 10, wherein the tag antenna includes an impedance matching network associated therewith.

12. An RFID system as defined in claim 1, wherein the tag antenna includes an impedance matching network associated therewith.

13. An RFID system as defined in claim 1, wherein the data signal includes a tag identifier.

14. An RFID system as defined in claim 13, wherein the tag identifier includes an identification number.

15. An RFID system, comprising:

a tag including an antenna that selectively transfers a data signal; and

a reader including an antenna that receives the data signal from the tag;

wherein the tag antenna and the reader antenna are over-coupled when the antennas are within 10 mm of each other.

16. An RFID system, comprising:

a tag including an antenna that selectively transfers a data signal, wherein the data signal includes a tag identifier; and

a reader including an antenna that receives the data signal from the tag;

wherein at least one of the tag antenna and the reader antenna have a Q-factor that is greater than 30;

wherein at least one of the tag antenna and the reader antenna include an impedance matching network associated therewith;

wherein the tag antenna and the reader antenna are over-coupled when the antennas are within 10 mm of each other.

17. An RFID system as defined in claim 16, wherein the tag is attached to a wristband worn by a user and the reader is attached to a door having a door lock mechanism and provides an unlock signal to the door lock mechanism.

18. An RFID system as defined in claim 17, wherein the door includes a generally planar door surface and a door latch actuator that pivots about a pivot axis, the door latch actuator including an elongated handle portion defining a handle axis that extends generally transversely from the pivot axis and generally parallel to the planar door surface, the reader being located in relation to the planar door surface in a position vertically offset from and spaced apart from the handle axis and horizontally offset from and spaced apart from the pivot axis.