RFID Reader/Interrogator Sub-Band Selection
AssigneeSymbol Technologies, Inc.
InventorsMark Duran, Richard T. Knadle, JR., Russell Calvarese
Life of this patent
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Abstract
Due to design constraints and installation variability, RFID interrogator antennas do not always function optimally across the entire channel on which they are intended to operate due to diminished antenna bandwidth. Techniques are described for selecting a sub-band of frequencies within the channel on which a particular RFID interrogator can be operated to enhance operating efficiency. These techniques include a VSWR measurement technique and a read/no read technique are disclosed for identifying a useful sub-band of frequencies. The operation of a reader/interrogator is then limited to an identified sub-band so that an RFID interrogator/tag system can be operated efficiently.
Claims15
A method for operating an RFID interrogator comprising:
- identifying a gross band of frequencies over which the interrogator is capable of operating;
- measuring characteristics of an antenna associated with the interrogator;
- and
- operating the interrogator within a sub-band of frequencies based upon characteristics of the antenna as measured.
A method for operating an RFID interrogator comprising:
- identifying a gross band of frequencies over which the RFID interrogator is capable of operating;
- measuring responses of test RFID tags at discrete frequencies within the gross band of frequencies;
- identifying a sub-band of frequencies within the gross band of frequencies in which the test RFID tags responded according to predetermined criteria;
- and
- operating the RFID interrogator only within the sub-band of frequencies.
An RFID tag system, comprising:
- an RFID tag;
- and
- an RFID interrogator, the RFID interrogator comprising:
- an antenna constructed and arranged to transmit interrogation signals to the RFID tag and to receive backscatter signals there from;
- control logic constructed and arranged to control the interrogator in a manner to cause it to send interrogation signals only on particular frequencies on which the interrogator has been previously determined to operate according to predetermined criteria.
Dependencies are inferred from the claim text.