RFID tags for enabling batch reading of stacks of cartons

• US 20050280512A1
• Filed: 06/22/2004
• Published: 12/22/2005
• 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
• Granted Patent: US 7,319,393 B2
• Time in Patent Office: Days
• US Class Current: 340/10.34
• 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 anther in another direction. When a plurality of tags are mounted to a plurality of objects, the now RFID-enabled objects can be read in batch, including the innermost objects in a stack and objects that may be block by an RF obstacle. The RFID tags are oriented on the objects so that when the objects are stacked together, the RFID tags are sequentially positioned in operative proximity with each other. Therefore, energy from a reader that is received by, e.g., an uppermost tag is propagated through the sequence tag by tag in one direction. In addition, tag energy modulated by the RFID circuit of each of the tags is propagated through the sequence tag by tag in the other direction. This two-dimensional propagation enables the RFID circuit of each tag of the RFID-enabled objects in the stack to be excited and to be read by the reader.

Claims

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

a pair of antennas for receiving activation energy;

an RFID circuit for modulating tag energy when activation energy is received by at least one of the antennas; and

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

a first one of the antennas for receiving activation energy;

a second one of the antennas for radiating activation energy received by the first antenna and for receiving tag energy radiated by an antenna of another RFID tag; and

the first antenna for radiating the tag energy received by the second antenna from the other RFID tag;

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 propagate through the sequence from one RFID tag to anther in another direction.

2. The RFID tag of claim 1 wherein the antennas are mountable to an object such that the antennas are disposed at or near respective opposing edges of the object.

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

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

5. The RFID tag of claim 4 wherein the antennas 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 antennas 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 antennas 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 9 wherein the transmission line includes a plurality of segments each electrically coupled to a respective one of the antennas and the RFID circuit.

12. The RFID tag of claim 11 wherein each of the segments of the transmission line is able to be coupled to another segment through capacitance.

13. The RFID tag of claim 1 wherein at least one of the antennas includes a free-space antenna.

14. The RFID tag of claim 1 wherein at least one of the antennas includes a proximity coupler.

15. The RFID tag of claim 1 wherein at least one of the antennas includes a dipole antenna.

16. The RFID tag of claim 1 wherein at least one of the antennas includes a notch antenna.

17. The RFID tag of claim 1 wherein at least one of the antennas includes a Yagi antenna.

18. The RFID tag of claim 1 wherein at least one of the antennas is configured to radiate energy in two dimensions.

19. The RFID tag of claim 1 further comprising a plurality of antennas configured to radiate energy in three dimensions.

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

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

22. The RFID tag of claim 1 wherein the RFID circuit includes an RFID chip having a variable input impedance.

23. A radio-frequency identification (RFID) tag for an object, the RFID tag for use with a reader, the object having a side with a dimension defined between opposing edges and being stackable with other such objects, the RFID tag comprising:

a substrate;

a first antenna disposed on the substrate;

a second antenna disposed on the substrate;

a transmission line coupled to the antennas; and

an RFID circuit electrically coupled to the transmission line and for being activated by radio-frequency (RF) energy;

the substrate having a dimension defined between the edges that enables the first antenna to be disposed at or near one of the edges of the side and the second antenna to be disposed at or near the other edge of the side.

24. 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 one of the sides of the object;

a transmission line electrically coupled to the antennas; and

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

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

25. 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 antennas; and

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; and

transmitting activation energy to the load.

26. The method of claim 25 further comprising receiving tag energy modulated sequentially from one RFID tag to another.

27. The method of claim 26 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.

28. A method for enabling an object to be read by an RFID reader, the method comprising:

providing an object having a side with a dimension defined between opposing edges;

providing an RFID tag including;

a pair of antennas for receiving activation energy;

an RFID circuit for modulating tag energy when activation energy is received by one of the antennas; and

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

a first one of the antennas for receiving activation energy;

a second one of the antennas for radiating activation energy received by the first antenna and for receiving tag energy radiated by an antenna of another RFID tag; and

the first antenna for radiating the tag energy received by the second antenna from the other RFID tag;

mounting the RFID tag to the side of the object such that the first antenna is disposed at or near one of the edges of the side of the object and the second antenna is disposed at or near the other edge of the side of the object.

29. The method of claim 28 wherein the antennas and the RFID circuit are each disposed on a substrate, the mounting step comprising mounting the substrate to the side of the object.

30. The method of claim 29 wherein the substrate includes adhesive, the mounting step comprising adhering the substrate to the side of the object.

31. The method of claim 28 wherein the mounting step includes mounting the RFID tag to the object such that the antennas are disposed on opposing sides of the object.

32. The method of claim 28 wherein the antennas and the RFID circuit are each disposed on a respective substrate with a transmission line segment coupled thereto, thereby defining a pair of antenna sections and an RFID circuit section, the mounting step comprising:

mounting the antenna sections to the side of the object; and

mounting the RFID circuit section to the side of the object by aligning and overlapping the transmission line segments of the RFID circuit section with the transmission line segments of the antenna sections.

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

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

an RFID tag including;

a top antenna disposed at or near the top edge of one of the sides of the object;

a bottom antenna disposed at or near the bottom edge of the one side of the object;

a transmission line electrically coupled to the antennas; and

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

whereby when a plurality of the RFID-enabled objects are vertically stacked, the bottom antenna of an upper one of the RFID-enabled objects is positioned within communicative proximity with the top antenna of a lower one of the RFID-enabled objects on which the first RFID-enabled object is stacked.

34. The RFID-enabled object of claim 33 wherein at least one of the antennas includes a free-space antenna.

35. The RFID-enabled object of claim 33 wherein at least one of the antennas includes a proximity coupler.

36. The RFID-enabled object of claim 33 wherein at least one of the antennas includes a dipole antenna.

37. The RFID-enabled object of claim 36 wherein the dipole radiator includes a pair of radiating elements disposed substantially parallel to the edges.

38. The RFID-enabled object of claim 37 wherein the dipole radiator includes a first radiating element disposed substantially parallel to the edges and a second radiating element disposed substantially perpendicular to the edges.

39. The RFID-enabled object of claim 33 wherein at least one of the antennas includes a notch antenna.

40. The RFID-enabled object of claim 33 wherein at least one of the antennas includes a Yagi antenna.

41. The RFID-enabled object of claim 33 wherein the RFID tag further includes a substrate on which the antennas, the transmission line, and the circuit are disposed.

42. The RFID-enabled object of claim 41 wherein the substrate includes adhesive for adhering to the object.

43. A method for reading a stack of radio-frequency identification (RFID)-enabled objects, each of the RFID-enabled objects having a top, a bottom, and four sides, the method comprising:

providing a stack of RFID-enabled objects each including;

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

an RFID tag including;

a top antenna disposed at or near the top edge of one of the sides of the object;

a bottom antenna disposed at or near the bottom edge of the one side of the object;

a transmission line coupled to the antennas; and

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

wherein the bottom antenna of an upper one of the RFID-enabled objects is positioned within communicative proximity with the top antenna of a lower one of the RFID-enabled objects on which the first RFID-enabled object is stacked;

causing the RFID circuits of the upper and lower RFID-enabled objects to be activated by transmitting energy to the stack of RFID-enabled objects for reception by the top antenna of the upper RFID-enabled object, thereby causing the lower antenna to radiate energy for reception by the top antenna of the lower RFID-enabled object.

44. A radio-frequency identification (RFID) tag for an object, the RFID tag comprising:

a substrate;

a pair of antennas disposed on the substrate;

a transmission line electrically coupled to the antennas; and

a circuit electrically coupled to the transmission line and for being activated by energy;

the substrate for mounting to one of the sides of the object such that;

one of the antennas is disposed at or near an edge of the side of the object; and

the other antenna is disposed at or near an opposing edge of the side of the object;

one of the antennas for receiving energy; and

the other antenna for radiating the received energy;

whereby when the RFID tag is mounted to one of the sides of the object and the object is stacked with another object having an RFID tag mounted similarly to one of its sides, the antenna for radiating the received energy is positioned in communicative proximity to the antenna for receiving energy of the other object.

45. The RFID tag of claim 44 wherein each of the antennas is capable of receiving and radiating energy.