RFID tags for enabling batch reading of stacks of cartons

• US 7,501,952 B2
• Filed: 08/21/2007
• Issued: 03/10/2009
• Est. Priority Date: 06/22/2004
• Status: Active Grant

• Current Assignee: Avery Dennison Retail Information Services LLC (Avery Dennison Corporation)
• Original Assignee: Avery Dennison Corporation
• Inventors: Forster, Ian James
• Primary Examiner(s): Previl; Daniel
• Application Number:
  US11/842,680
• Publication Number:
  US 20070285247A1
• Time in Patent Office: 567 Days
• Field of Search: 3405721-5729, 340/568.1, 340/825.36, 340/825.49, 340/10.1, 340/10.3, 340/10.34
• US Class Current: 340/572.1
• CPC Class Codes: B65D 2203/10 Transponders
• CPC Class Codes: G06K 19/0701 at least one of the integrated circuit chips comprising an arrangement for power management
• 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 19/07796 arrangements on the record carrier to allow stacking of a plurality of similar record carriers, e.g. to avoid interference between the non-contact communication of the plurality of record carriers
• 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 7/10019 resolving collision on the communication channels between simultaneously or concurrently interrogated record carriers. collision between the communication channels used by wireless communication devices, where the solution is not particularly adapted for RFIDs or the like, H04W74/08
• CPC Class Codes: G06K 7/10336 the antenna being of the near field type, inductive coil
• CPC Class Codes: H01Q 1/2208 associated with components used in interrogation type services, i.e. in systems for information exchange between an interrogator/reader and a tag/transponder, e.g. in Radio Frequency Identification [RFID] systems methods or arrangements for sensing record carriers, e.g. for reading patterns G06K7/00; record carrier for use with machines and with at least a part designed to carry digital markings G06K19/00
• CPC Class Codes: H01Q 19/30 the primary active element being centre-fed and substantially straight, e.g. Yagi antenna
• CPC Class Codes: H01Q 9/065 Microstrip dipole antennas patch antenna H01Q9/0407

Abstract

A radio-frequency identification (RFID) system including an RFID tag and an RFID-enabled object. The RFID tag may include a pair of antennas and an RFID circuit. The antennas receive activation energy from a reader, and the RFID circuit modulates tag energy when activation energy is received by one of the antennas. The tag may also include a transmission line for operatively coupling the RFID circuit to the antennas. A first one of the antennas may receive activation energy which, in turn, may be radiated by a second one of the antennas. The second antenna may also receive tag energy radiated by an antenna of another RFID tag. The received tag energy may then be radiated by the first antenna. Accordingly, when a plurality of the RFID tags are positioned in sequence in operative proximity with each other, activation energy may be propagated through the sequence from one RFID tag to another in one direction, and tag energy may be propagated through the sequence from one RFID tag to another in another direction.

Claims

1. A radio-frequency identification (RFID) tag for use with a reader that generates activation energy, the RFID tag comprising:

an RFID circuit for modulating tag energy when activation energy is received and for modulating tag energy when tag energy is received from another RFID tag;

a first antenna configured to receive and provide activation energy to the RFID circuit and radiate modulated tag energy received from the RFID circuit;

a second antenna configured to radiate activation energy received by the first antenna and receive and provide tag energy radiated by antenna from another RFID tag to the RFID circuit;

a transmission line for operatively coupling the RFID circuit to the first and second antennas;

whereby when a plurality of the RFID tags are positioned in sequence in operative proximity with each other, activation energy is propagated through the sequence from one RFID tag to another in one direction, and tag energy is propagated through the sequence from one RFID tag to another in another direction;

wherein the RFID circuit comprises an RFID chip having a variable input impedance, the variable input impedance including a first state in which the RFID chip absorbs energy from the transmission line, a second state in which energy from the transmission line is reflected back, and a third state in which the amount of energy absorbed by the RF chip is minimized, thereby maximizing the amount of energy passed on to a next RFID tag.

2. The RFID tag of claim 1 wherein the first antenna and the second antenna are both mounted to a side of an object such that the first antenna and the second antenna are disposed at or near respective opposing edges of the side of the object.

3. The RFID tag of claim 1 wherein the first antenna and the second antenna are mountable to an object such that the first antenna and the second antenna are disposed on opposing sides of the object.

4. The RFID tag of claim 1 wherein the first antenna and the second antenna and the RFID circuit are each disposed on a substrate.

5. The RFID tag of claim 4 wherein the first antenna and the second antenna and the RFID circuit are disposed on a single substrate.

6. The RFID tag of claim 5 wherein the substrate includes an adhesive layer.

7. The RFID tag of claim 5 wherein the first antenna and the second antenna are disposed at or near respective opposing edges of the substrate.

8. The RFID tag of claim 7 wherein the substrate is mountable to a side of an object having a dimension defined between opposing edges of the side;

the substrate having a dimension between the opposing edges thereof that is substantially equal to the dimension of the side of the object.

9. The RFID tag of claim 4 wherein the first antenna and the second antenna and the RFID circuit are each disposed on a respective substrate.

10. The RFID tag of claim 9 wherein each of the substrates includes an adhesive layer.

11. The RFID tag of claim 1 wherein at least one of the first antenna and the second antenna includes a free-space antenna.

12. The RFID tag of claim 1 wherein at least one of the first antenna and the second antenna includes a proximity coupler.

13. The RFID tag of claim 1 wherein at least one of the first antenna and the second antenna includes a dipole antenna.

14. The RFID tag of claim 1 wherein at least one of the first antenna and the second antenna includes a notch antenna.

15. The RFID tag of claim 1 wherein at least one of the first antenna and the second antenna includes a Yagi antenna.

16. The RFID tag of claim 1 wherein at least one of the first antenna and the second antenna is configured to radiate energy in two dimensions.

17. The RFID tag of claim 1 wherein at least one of the first antenna and the second antenna is configured to radiate energy in three dimensions.

18. The RFID tag of claim 1 wherein the RFID circuit includes a switch for coupling the RFID chip to the first antenna and for decoupling the RFID chip from the first antenna when the RFID tag has been read by the reader.

19. The RFID tag of claim 1 wherein the RFID circuit includes an amplifier for amplifying the tag energy received by the second antenna.

20. A radio-frequency identification (RFID)-enabled object for use with a reader, the RFID-enabled object comprising:

an object having a top, a bottom, and four sides each having four edges; and

an RFID tag including;

a first antenna disposed at or near one of the edges of one of the sides of the object;

a second antenna disposed at or near another one of the edges of the one of the sides of the object, the first and second antenna being mounted to the one of the sides of the object;

a transmission line electrically coupled to the first antenna and the second antenna; and

an RFID circuit electrically coupled to the transmission line for communicating with the reader when activated by energy from the reader system, wherein the RFID circuit comprises an RFID chip having a variable input impedance, the variable input impedance including a first state in which the RFID chip absorbs energy from the transmission line, a second state in which energy from the transmission line is reflected back, and a third state in which the amount of energy absorbed by the RF chip is minimized, thereby maximizing the amount of energy passed on to a next RFID-enabled object;

the object being stackable with another RFID-enabled object such that either one of the first and the second antennas is positioned within communicative proximity with an antenna of the other RFID-enabled object.

21. A method of reading radio-frequency identification (RFID)-enabled objects, the method comprising:

providing a load of a plurality of RFID-enabled objects stacked together, each of the objects including;

an object having a top, a bottom, and four sides each having four edges; and

a RFID tag including;

a first antenna disposed at or near one of the edges of one of the sides of the object;

a second antenna disposed at or near another one of the edges of one of the sides of the object;

a transmission line electrically coupled to the first antenna and the second antenna;

an RFID circuit electrically coupled to the transmission line for communicating with the reader when activated by energy from the reader system;

the objects being stacked with one another such that the RFID tags are positioned sequentially in operative proximity with one another;

transmitting activation energy to the load;

sequentially propagating activation energy from one RFID tag to another; and

sequentially modulating tag energy from one RFID tag to another by a corresponding RFID circuit;

wherein the RFID circuit comprises an RFID chip having a variable input impedance, the variable input impedance including a first state in which the RFID chip absorbs energy from the transmission line, a second state in which energy from the transmission line is reflected back, and a third state in which the amount of energy absorbed by the RF chip is minimized, thereby maximizing the amount of energy passed on to a next RFID tag.

22. The method of claim 21 wherein the first antenna of at least one of the RFID-enabled objects has a line of sight with a reader, and the second antenna of the at least one RFID-enabled object has no line of sight with a reader, further comprising modulating tag energy from one RFID tag to another by proximity coupling.