Radio frequency identification tag identification system
First Claim
Patent Images
1. A conveyor system for processing items on which radio frequency identification tags are disposed, said system comprising:
- a conveyor that conveys items through a path of travel, each item having at least one respective radio frequency identification tag disposed thereon;
circuitry in communication with the conveyor that tracks a position of items in the path of travel; and
an antenna disposed proximate the path of travel so that the antenna radiates radio frequency signals into the path of travel, wherein the antenna comprises at least one first element and at least one second element that radiate the radio frequency signals and that receive responses to the radio frequency signals from radio frequency identification tags disposed on the items being conveyed by the conveyor through the path of travel, and wherein the at least one first element is disposed upstream from the at least one second element with respect to the path of travel;
wherein the circuitryreceives signals from the at least one first element and the at least one second element corresponding to the responses, andprovides output signals in response to the responses, wherein, for respective said responses, a magnitude of a said output signal corresponds to a difference between magnitude of a said signal corresponding to the response from one of the at least one first element and the at least one second element and magnitude of a signal corresponding to the response from the other of the at least one first element and the at least one second element;
wherein the circuitry is configured to monitor the output signals and to associate information corresponding to a said radio frequency tag with a said item based upon when the magnitude of the output signals reach a minimum.
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Abstract
A conveyor system for processing items on which radio frequency identification tags are disposed has a conveyor that conveys items through a path of travel, and an antenna disposed proximate the path of travel. Circuitry in communication with the antenna may associate RFID tag data with a package on the conveyor based on a difference signal from elements in the antenna.
63 Citations
26 Claims
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1. A conveyor system for processing items on which radio frequency identification tags are disposed, said system comprising:
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a conveyor that conveys items through a path of travel, each item having at least one respective radio frequency identification tag disposed thereon; circuitry in communication with the conveyor that tracks a position of items in the path of travel; and an antenna disposed proximate the path of travel so that the antenna radiates radio frequency signals into the path of travel, wherein the antenna comprises at least one first element and at least one second element that radiate the radio frequency signals and that receive responses to the radio frequency signals from radio frequency identification tags disposed on the items being conveyed by the conveyor through the path of travel, and wherein the at least one first element is disposed upstream from the at least one second element with respect to the path of travel; wherein the circuitry receives signals from the at least one first element and the at least one second element corresponding to the responses, and provides output signals in response to the responses, wherein, for respective said responses, a magnitude of a said output signal corresponds to a difference between magnitude of a said signal corresponding to the response from one of the at least one first element and the at least one second element and magnitude of a signal corresponding to the response from the other of the at least one first element and the at least one second element; wherein the circuitry is configured to monitor the output signals and to associate information corresponding to a said radio frequency tag with a said item based upon when the magnitude of the output signals reach a minimum.
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2. A conveyor system for processing items on which radio frequency identification tags are disposed, said system comprising:
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a conveyor that conveys items through a path of travel, each item having at least one respective radio frequency identification tag disposed thereon; a sensor disposed proximate the path of travel so that the sensor detects presence of items in the path of travel; circuitry in communication with the sensor and the conveyor that tracks a position of each item with respect to the path of travel; and an antenna disposed proximate the path of travel so that the antenna radiates radio frequency signals into the path of travel, including to a predetermined position in the path of travel, wherein the antenna comprises at least one first element and at least one second element that radiate the radio frequency signals and that receive responses to the radio frequency signals from radio frequency identification tags disposed on the items being conveyed by the conveyor through the path of travel, and wherein the at least one first element is disposed upstream from the at least one second element with respect to the path of travel; wherein the circuitry receives signals from the at least one first element and the at least one second element corresponding to the responses, and provides output signals in response to the responses, wherein, for respective said responses, a magnitude of a said output signal corresponds to a difference between magnitude of a said signal corresponding to the response from one of the at least one first element and the at least one second element and magnitude of a signal corresponding to the response from the other of the at least one first element and the at least one second element; wherein the antenna is disposed with respect to the path of travel so that the magnitude of the output signals is at a minimum when the radio frequency identification tag from which the at least one first element and the at least one second element receive the responses is at the predetermined position; and wherein the circuitry is configured to monitor the output signals and to associate information corresponding to a said radio frequency identification tag with a said item based upon proximity of the item to the predetermined position when the magnitude of the output signals reach the minimum. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A conveyor system for processing items on which radio frequency identification tags are disposed, said system comprising:
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a conveyor that conveys items through a path of travel, each item having at least one respective radio frequency identification tag disposed thereon; a sensor disposed proximate the path of travel so that the sensor detects presence of items in the path of travel; circuitry in communication with the sensor and the conveyor that tracks a position of each item with respect to the path of travel; and an antenna disposed proximate the path of travel so that the antenna radiates radio frequency signals into the path of travel, including to a predetermined position in the path of travel, wherein the antenna comprises at least one first element and at least one second element that radiate the radio frequency signals and that receive responses to the radio frequency signals from radio frequency identification tags disposed on the items being conveyed by the conveyor through the path of travel, and wherein the at least one first element is disposed upstream from the at least one second element with respect to the path of travel; wherein the circuitry receives signals from the at least one first element and the at least one second element corresponding to the responses, provides first and second output signals in response to the responses, wherein, for respective said responses, a magnitude of a said first output signal corresponds to a difference between magnitude of a said signal corresponding to the response from one of the at least one first element and the at least one second element and magnitude of a said signal corresponding to the response from the other of the at least one first element and the at least one second element, and a magnitude of a said second output signal corresponds to a sum of the magnitude of the signal from the one of the at least one first element and the at least one second element and the magnitude of the signal from the other of the at least one first element and the at least one second element, for respective instances of said signals from the at least one first element and the at least one second element, determines a first difference between the magnitude of the first output signal and the magnitude of the second output signal, and for respective instances of said signals from the at least one first element and the at least one second element received correspondingly to responses from an individual radio frequency identification tag, determines a second difference between the first difference for each said correspondingly received respective instance and the first difference from a preceding said correspondingly received respective instance; wherein the antenna is disposed with respect to the path of travel so that the magnitude of the first output signals is at a minimum when the radio frequency identification tag from which the at least one first element and the at least one second element receive the responses is at the predetermined position and the magnitude of the second output signals is at a maximum when the radio frequency identification tag from which the at least one first element and the at least one second element receive the responses is at the predetermined position; and wherein the circuitry is configured to monitor the first and second output signals and to associate information corresponding to the individual radio frequency identification tag with a said item based upon change in polarity of the second difference.
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15. A conveyor system for processing items on which radio frequency identification tags are disposed, said system comprising:
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a conveyor that conveys items through a path of travel, each item having at least one respective radio frequency identification tag disposed thereon; an antenna disposed with respect to the path of travel so that the antenna radiates radio frequency signals into a first area through which the items pass, wherein the antenna comprises a substrate and a plurality of patch elements having respective generally planar surfaces, wherein the generally planar surfaces of the patch elements are generally coplanar, wherein the antenna includes a feed network that applies respective signals to each said patch element that drive electric current at the patch elements to radiate the radio frequency signals, and wherein the respective signals applied by the feed network to at least two said patch elements define a predetermined phase shift of approximately 79 degrees with respect to each other that is fixed so that respective electric current patterns on the at least two patch elements are out of phase with respect to each other; and a radio frequency transmitter that drives the antenna to emit the radio frequency signals into the first area. - View Dependent Claims (16, 17)
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18. A conveyor system for processing items on which radio frequency identification tags are disposed, said system comprising:
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a conveyor that conveys items through a path of travel, each item having at least one respective radio frequency identification tag disposed thereon; an antenna disposed with respect to the path of travel so that the antenna radiates radio frequency signals into a first area through which the items pass, wherein the antenna comprises a substrate and a plurality of patch elements having respective generally planar surfaces, wherein the generally planar surfaces of the patch elements are generally coplanar, wherein the antenna includes a feed network that applies respective signals to each said patch element that drive electric current at the patch elements to radiate the radio frequency signals; and a radio frequency transmitter that drives the antenna to emit the radio frequency signals into the first area, wherein the feed network comprises a switch that selectively connects at least one of the patch elements to the transmitter over a first feed line in a first position of the switch and a second feed line in a second position of the switch, wherein the first feed line and the second feed line define a relative difference in length with respect to frequency of the signals applied to the patch elements so that a predetermined difference in phase is defined between the radio frequency signals radiated by the at least one of the patch elements when the switch is in the first position and the radio frequency signals radiated by the at least one of the patch elements when the switch is in the second position. - View Dependent Claims (19, 20, 21, 22)
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23. A method for reading radio frequency identification tags disposed on items being conveyed through a path of travel by a conveyor system, the method comprising the steps of:
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providing a drive signal from a radio frequency transmitter to an antenna disposed with respect to the path of travel so that the antenna radiates radio frequency signals into a first area through which the items pass, wherein the antenna comprises a substrate, a plurality of generally coplanar patch elements, and a feed network that applies respective signals from the radio frequency transmitter to each said patch element, and wherein the feed network comprises a switch that selectively connects at least one of the patch elements to the transmitter over a first feed line in a first position of the switch and a second feed line in a second position of the switch, wherein the first feed line and the second feed line define a relative difference in length with respect to frequency of the signals applied to the patch elements so that a predetermined difference in phase is defined between the radio frequency signals radiated by the at least one of the patch elements when the switch is in the first position and the radio frequency signals radiated by the at least one of the patch elements when the switch is in the second position; measuring a distance between a first said item and a second said item; and activating the switch based on an analysis of the distance. - View Dependent Claims (24, 25, 26)
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Specification