RFID material tracking method and apparatus
First Claim
Patent Images
1. An antenna, comprising:
- a single layer flat metallic coil;
a capacitor connected in series with the coil; and
a diode having its anode connected between the coil and the capacitor, the diode generating a rectified peak voltage indicative of the load on the capacitor and coil.
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Abstract
A method and apparatus for tracking items automatically is described. A passive RFID (Radio Frequency IDentification) tag is used with a material tracking system capable of real-time pinpoint location and identification of thousands of items in production and storage areas. Passive RFID tags are attached to the item to be tracked, remote sensing antennas are placed at each remote location to be monitored, interrogators with several antenna inputs are connected to the sensing antennas to multiplex the antenna signals, and a host computer communicates with the interrogators to determine item locations to an exacting measure.
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Citations
39 Claims
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1. An antenna, comprising:
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a single layer flat metallic coil;
a capacitor connected in series with the coil; and
a diode having its anode connected between the coil and the capacitor, the diode generating a rectified peak voltage indicative of the load on the capacitor and coil. - View Dependent Claims (2, 3, 4)
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5. An antenna for use in a passive RFID interrogation system, comprising:
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a coil of metal arranged in a flat radial single layer formation; and
a capacitor connected in series with the coil. - View Dependent Claims (6, 7, 8)
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9. An antenna, comprising:
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a flat single layer coil of metal; and
a conductive plate in the same plane as the flat single layer coil of metal and separated by a predetermined distance from the plane of the coil, the metal plate preloading the coil to reduce sensitivity of the coil to other ferrous material. - View Dependent Claims (10, 11, 12, 14, 15, 16, 18, 19, 20, 21)
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13. An antenna, comprising:
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a substantially circular core, having an annular ring protruding substantially perpendicular to the plane of the core, and having a substantially centered core post extending substantially perpendicular to the plane of the core; and
a coil wound around the post between the post and the annular ring.
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17. An antenna for connection to a multiple input interrogator having a common detection circuit, the antenna comprising:
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a flat coil;
a capacitor connected with the flat coil to form a tuned circuit; and
a diode having its anode connected between the coil and the capacitor, the diode generating a rectified peak voltage indicative of the load on the capacitor and coil.
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22. An antenna for use in a RFID interrogation system, comprising:
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a substantially circular core, having an annular ring protruding substantially perpendicular to the plane of the core, and having a substantially centered core post extending substantially perpendicular to the plane of the core;
a coil wound around the post between the post and the annular ring; and
a capacitor connected in series with the coil. - View Dependent Claims (23, 24, 25, 26, 28, 29, 30, 31, 32)
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27. An antenna for connection to a multiple input interrogator having a common detection circuit, the antenna comprising:
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a substantially circular core, having an annular ring protruding substantially perpendicular to the plane of the core, and having a substantially centered core post extending substantially perpendicular to the plane of the core;
a coil wound around the post between the post and the annular ring;
a capacitor connected to the coil to form a tuned circuit; and
a diode having its anode connected between the coil and the capacitor, the diode generating a rectified peak voltage indicative of the load on the capacitor and coil.
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33. An antenna array for use in a RFID interrogation system, comprising:
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a first antenna including a first coil of metal arranged in a flat radial single layer formation, the first coil connected in series with a first capacitor; and
a second antenna including a substantially circular core, having an annular ring protruding substantially perpendicular to the plane of the core, and having a substantially centered core post extending substantially perpendicular to the plane of the core, a second coil wound around the post between the post and the annular ring, the second coil connected in series with a second capacitor. - View Dependent Claims (34, 35, 36, 37, 38, 39)
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Specification