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US 8,505,829 B2Granted
RFID tag sensors and methods
AssigneeWal-Mart Stores, Inc.
InventorBruce W. Wilkinson
Life of this patent
Estimating the term…
Abstract
Radio frequency identification (RFID) devices for use in RFID-based sensors and related methods are described herein. In one implementation, an RFID sensor system includes an RFID device having a near field only RFID tag and a conductive element which functions as a far field antenna. The near field only RFID tag and the conductive element are located in at least a first position and a second position relative to each other; wherein in the first position, the RFID device only operates in a near field, and in the second position, the RFID device operates in both the near field and a far field. The system may also include an RFID reader and controller located within the far field to read the RFID device only when the components are located in the second position.
Claims42
A radio frequency identification (RFID) sensor system comprising:
- an RFID device comprising:
- a near field only RFID tag, wherein the near field only RFID tag in and of itself does not function as a far field RFID tag;
- a conductive element independent from the near field only RFID tag and configured to function as a far field antenna;
- and
- wherein the near field only RFID tag and the conductive element are configured to be located in at least a first position and a second position relative to each other;
- wherein the first position locates the near field only RFID tag and the conductive element relative to each other such that the conductive element is sufficiently decoupled from the near field only RFID tag in order that the RFID device only operates in a near field with respect to an RFID reader;
- and
- wherein the second position locates the near field only RFID tag and the conductive element relative to each other such that the conductive element is sufficiently coupled to the near field only RFID tag such that the RFID device operates in both the near field and a far field with respect to the RFID reader.
5 more elements
A method for using a radio frequency identification (RFID) device as a sensor comprising:
- providing the RFID device comprising a near field only RFID tag and a conductive element, wherein the near field only RFID tag in and of itself does not function as a far field RFID tag, wherein the conductive element is configured to function as a far field antenna, wherein the near field only RFID tag and the conductive element are in one of a proximity relationship and a non-proximity relationship relative to each other,
- wherein, when in the proximity relationship, the near field only RFID tag and the conductive element are sufficiently decoupled from each other in order that the RFID device only operates in a near field with respect to an RFID reader,
- wherein, when in the non-proximity relationship, the near field only RFID tag and the conductive element are sufficiently coupled to each other such that the RFID device operates in both the near field and the far field with respect to the RFID reader;
- and
- moving the near field only RFID tag and the conductive element from the one of the proximity relationship and the non-proximity relationship to another of the proximity relationship and the non-proximity relationship relative to each other.
2 more elements
A radio frequency identification (RFID) sensor system comprising:
- an RFID device comprising:
- a plurality of near field only RFID tags, wherein each near field only RFID tag in and of itself does not function as a far field RFID tag;
- a conductive element independent from the plurality of near field only RFID tags and configured to function as a far field antenna;
- and
- wherein the conductive element is configured to be located in at least a first position and a second position relative to the plurality of near field only RFID tags;
- wherein the first position locates the conductive element such that the conductive element is sufficiently coupled to a first one of the plurality of near field only RFID tags in order that the first one of the plurality of near field only RFID tags is readable in both a near field and a far field with respect to an RFID reader, and the conductive element is sufficiently decoupled from others of the plurality of near field only RFID tags such that the others of the plurality of near field only RFID tags are only readable in the near field with respect to the RFID reader;
- and
- wherein the second position locates the conductive element such that the conductive element is sufficiently coupled to a second one of the plurality of near field only RFID tags in order that the second one of the plurality of near field only RFID tags is readable in both the near field and the far field with respect to the RFID reader, and the conductive element is sufficiently decoupled from the first one and the others of the plurality of near field only RFID tags such that the first one and the others of the plurality of near field only RFID tags are only readable in the near field with respect to the RFID reader.
5 more elements
A radio frequency identification (RFID) sensor system comprising:
- an RFID device comprising:
- a near field only RFID tag that in and of itself does not function as a far field RFID tag;
- a plurality of conductive elements each independent from the near field only RFID tag and each configured to function as a far field antenna;
- and
- wherein the near field only RFID tag is configured to be located in at least a first position and a second position relative to the plurality of conductive elements;
- wherein the first position locates the near field only RFID tag such that the near field only RFID tag is sufficiently coupled to a first one of the plurality of conductive elements in order that the near field only RFID tag is readable in both a near field and a far field with respect to an RFID reader, and the near field only RFID tag is sufficiently decoupled from others of the plurality of conductive elements;
- and
- wherein the second position locates the near field only RFID tag such that the near field only RFID tag is sufficiently coupled to a second one of the plurality of conductive elements in order that the near field only RFID tag is readable in both the near field and the far field with respect to the RFID reader, and the near field only RFID tag is sufficiently decoupled from the first one and the others of the plurality of conductive elements.
5 more elements
Dependencies are inferred from the claim text.