RFID TAG INTERROGATION SYSTEMS
1 Assignment
0 Petitions
Accused Products
Abstract
We describe an RFID tag reading system comprising a plurality of transmit/receive antennas to provide spatial transmit/receive signal diversity, and a tag signal decoder. The system combines received RF signals from the antennas, and the antennas are spaced apart from one another sufficiently for one said antenna not to be within the near field of another. The system performs a tag inventory cycle comprising a plurality of tag read rounds, each having a set of time slots during which a said tag is able to transmit tag data including a tag ID. The system is configured to perform, during a tag inventory cycle, one or both of: a change in a frequency of the tag interrogation signals transmitted simultaneously from the plurality of antennas, and a change in a relative phase of a the RF tag interrogation signal transmitted from one of the antennas with respect to another.
24 Citations
38 Claims
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1-19. -19. (canceled)
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20. An RFID tag reading system for reading one or more RFID Tags, the system comprising an RF transmitter and an RF receiver, a plurality of transmit/receive antennas coupled to said RF transmitter and to said RF receiver, to provide spatial transmit/receive signal diversity, and a tag signal decoder coupled to at least said RF receiver, wherein said system is configured to combine received RF signals from said antennas to provide a combined received RF signal, wherein said RF receiver has said combined received RF signal as an input;
- wherein said antennas are spaced apart from one another sufficiently for one said antenna not to be within the near field of another said antenna, wherein said system is configured to perform a tag inventory cycle comprising a plurality of tag read rounds to read said tags, a said tag read round comprising transmission of an RF tag interrogation signal simultaneously from said plurality of antennas and receiving a signal from one or more of said tags, a said tag read round having a set of time slots during which a said tag is able to transmit tag data including a tag ID for reception by said antenna, and wherein said system is configured to perform, during a said tag inventory cycle, one or both of;
a change in a frequency of said tag interrogation signal transmitted simultaneously from said plurality of antennas, and a change in a relative phase of a said RF tag interrogation signal transmitted from one of said antennas with respect to another of said antennas. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 36, 37)
- wherein said antennas are spaced apart from one another sufficiently for one said antenna not to be within the near field of another said antenna, wherein said system is configured to perform a tag inventory cycle comprising a plurality of tag read rounds to read said tags, a said tag read round comprising transmission of an RF tag interrogation signal simultaneously from said plurality of antennas and receiving a signal from one or more of said tags, a said tag read round having a set of time slots during which a said tag is able to transmit tag data including a tag ID for reception by said antenna, and wherein said system is configured to perform, during a said tag inventory cycle, one or both of;
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32. A method of using an RFID tag reading system for reading one or more RFID tags, the system comprising an RF transmitter and an RF receiver, a plurality of transmit/receive antennas coupled to said RF transmitter and to said RF receiver, to provide spatial transmit/receive signal diversity, and a tag signal decoder coupled to at least said RF receiver, wherein said system is configured to combine received RF signals from said antennas to provide a combined received RF signal, wherein said RF receiver has said combined received RF signal as an input;
- wherein said antennas are spaced apart from one another sufficiently for one said antenna not to be within the near field of another said antenna, wherein said system is configured to perform a tag inventory cycle comprising a plurality of tag read rounds to read said tags, a said tag read round comprising transmission of an RF tag interrogation signal simultaneously from said plurality of antennas and receiving a signal from one or more of said tags, a said tag read round having a set of time slots during which a said tag is able to transmit tag data including a tag ID for reception by said antenna, the method comprising changing, during a said tag inventory cycle, one or both of;
a relative phase of a said RF tag interrogation signal transmitted from one of said antennas with respect to another of said antennas, and a frequency of said tag interrogation signal transmitted simultaneously from said plurality of antennas. - View Dependent Claims (33, 34, 35, 38)
- wherein said antennas are spaced apart from one another sufficiently for one said antenna not to be within the near field of another said antenna, wherein said system is configured to perform a tag inventory cycle comprising a plurality of tag read rounds to read said tags, a said tag read round comprising transmission of an RF tag interrogation signal simultaneously from said plurality of antennas and receiving a signal from one or more of said tags, a said tag read round having a set of time slots during which a said tag is able to transmit tag data including a tag ID for reception by said antenna, the method comprising changing, during a said tag inventory cycle, one or both of;
Specification