Array Antenna System and Algorithm Applicable to RFID Readers
First Claim
1. An antenna system, comprising:
- an RF input port, wherein the RF input port receives an input RF signal, wherein the input RF signal is suitable for reading at least one RFID tag;
a plurality of antennas capable of producing RF fields in a region of interest;
a means for producing a corresponding plurality of antenna input signals from the input RF signal, wherein each of the plurality of antenna input signals is suitable for reading the at least one RFID tag, wherein when the plurality of antenna input signals is inputted to the plurality of antennas a corresponding plurality of RF fields is produced in the region of interest;
a state controller, wherein the state controller changes a state of the plurality of antennas by altering the plurality of RF fields, wherein the state controller produces a first state during a first period of time and produces a second state during a second period of time,
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Accused Products
Abstract
Embodiments of the invention pertain to Radio Frequency Identification (RFID) method and system using an antenna array, an array controller, and control algorithms. Embodiments of the invention can induce strong radio-frequency (RF) excitation, for a given level of radiated RF power, at any point within an arbitrary inhomogeneous medium. For RFID applications, one typical inhomogeneous medium is an ensemble of cases on a pallet. Another typical medium is a warehouse environment having stored goods together with shelving and other material present. An embodiment of the invention is applicable to the process of reading battery-less, or “passive” RFID tags, which rely on incident RF electromagnetic fields established by RFID readers to power the electronic circuitry within the tags.
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Citations
60 Claims
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1. An antenna system, comprising:
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an RF input port, wherein the RF input port receives an input RF signal, wherein the input RF signal is suitable for reading at least one RFID tag; a plurality of antennas capable of producing RF fields in a region of interest; a means for producing a corresponding plurality of antenna input signals from the input RF signal, wherein each of the plurality of antenna input signals is suitable for reading the at least one RFID tag, wherein when the plurality of antenna input signals is inputted to the plurality of antennas a corresponding plurality of RF fields is produced in the region of interest; a state controller, wherein the state controller changes a state of the plurality of antennas by altering the plurality of RF fields, wherein the state controller produces a first state during a first period of time and produces a second state during a second period of time, - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 48, 49)
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31. A method of reading one or more RFID tags, comprising:
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positioning one or more RFID tags in a region of interest; positioning a plurality of antennas, wherein the plurality of antennas is capable of producing RF fields in the region of interest; receiving an input RF signal, wherein the input RF signal is suitable for reading at least one of the one or more RFID tags; producing a corresponding plurality of antenna input signals from the received input RF signal, each of the plurality of antenna input signals suitable for reading at least one of the one or more RFID tags; inputting each of the plurality of antenna input signals into a corresponding antenna of the plurality of antennas. such that a corresponding plurality of RF fields are simultaneously produced in the region of interest from the plurality of antennas while the plurality of RF fields are in a first state during a first period of time; receiving a first return RF signal, wherein the first return RF signal is due to the plurality of RF fields produced during the first period of time being incident on the at least one of the one or more RFID tags; processing the first return RF signal to determine whether the at least one of the one or more RFID tags is present in the region of interest; inputting each of the plurality of antenna input signals into the corresponding antenna of the plurality of antennas, such that the corresponding plurality of RF fields are simultaneously produced in the region of interest from the plurality of antennas while the plurality of RF fields are in a second state during a second period of time, wherein the second state is accomplished by altering the plurality of RF fields produced in the region of interest; receiving a second return RF signal, wherein the second return RF signal is due to the plurality of RF fields produced during the second period of time being incident on the at least one of the one or more RFID tags; processing the second return RF signal to determine whether the at least one of the one or more RFID tags is present in the region of interest. - View Dependent Claims (32, 33, 34, 35, 36, 37, 38, 43, 44, 45, 46, 47, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60)
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- 39. The method according to claim 39, wherein the criterion is all of the one or more RFID tags in the region of interest are present.
Specification