Antenna systems for passive RFID tags
First Claim
1. An antenna system for a radio-frequency identification (RFID) tag, comprising:
- an antenna substrate;
an integrated circuit (IC) disposed on an end of the antenna substrate or adjacent to the end of the antenna substrate;
at least one serpentine antenna element having a first length and formed on the antenna substrate and electrically connected to the IC and extending from the IC in a first direction;
a conducting wire having a second length different from the first length electrically connected to either the IC or the at least one serpentine antenna element and extending on the antenna substrate in the first direction or substantially in the first direction; and
a shunt electrically connected to the at least one serpentine antenna element and to the conducting wire, the shunt configured to facilitate impedance matching between the antenna system and the IC.
4 Assignments
0 Petitions
Accused Products
Abstract
Antenna systems for passive radio-frequency identification (RFID) tags. The antenna systems have a very small form factor with good power harvesting and good performance in proximity to other antennas. The antenna system includes at least one, and preferably two, parallel serpentine antenna elements formed on, or otherwise supported by, an antenna substrate so that a RFID-tag integrated circuit (IC) can be electrically contacted to the antenna system at one end of the antenna substrate. A conducting wire that runs in the same direction as the at least one serpentine antenna element is used to match impedance and enhance antenna performance and power flow between the antenna and the IC. An impedance-matching circuit may be employed in place of the conducting wire to facilitate impedance matching between the antenna and the IC.
131 Citations
28 Claims
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1. An antenna system for a radio-frequency identification (RFID) tag, comprising:
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an antenna substrate; an integrated circuit (IC) disposed on an end of the antenna substrate or adjacent to the end of the antenna substrate; at least one serpentine antenna element having a first length and formed on the antenna substrate and electrically connected to the IC and extending from the IC in a first direction; a conducting wire having a second length different from the first length electrically connected to either the IC or the at least one serpentine antenna element and extending on the antenna substrate in the first direction or substantially in the first direction; and a shunt electrically connected to the at least one serpentine antenna element and to the conducting wire, the shunt configured to facilitate impedance matching between the antenna system and the IC. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. An antenna system for a radio-frequency identification (RFID) tag that includes an integrated circuit (IC), comprising:
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an antenna substrate having a proximal end and a distal end; a first serpentine antenna element and a second serpentine antenna element, the first and second serpentine antenna elements each supported by the antenna substrate and each having a proximal end and a distal end; first and second antenna feed points arranged at the antenna substrate proximal end and connected to the respective proximal ends of the first and second serpentine antenna elements so as to provide an electrical connection to the IC, which is arranged adjacent the antenna substrate proximal end; a conducting wire electrically connected to either the first or second serpentine antenna element or the first or second antenna feed point, such that the antenna length of either the first or second serpentine antenna element is longer than the antenna length of the second or first serpentine antenna element, respectively; and a shunt electrically connected to the first and second serpentine antenna elements or one of the first and second serpentine antenna elements and the conducting wire, the shunt configured to facilitate impedance matching between the antenna system and the IC. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23)
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24. An antenna system for a radio-frequency identification (RFID) tag that includes an integrated circuit (IC), comprising:
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an antenna substrate having a proximal end and a distal end; a first serpentine antenna element and a second serpentine antenna element, the first and second serpentine antenna elements each supported by the antenna substrate and each having a proximal end and a distal end; first and second antenna feed points arranged at the antenna substrate proximal end and electrically connected to the respective proximal ends of the first and second serpentine antenna elements so as to provide an electrical connection to the IC, which is arranged adjacent the antenna substrate proximal end; a conducting wire electrically connected to either the first or second serpentine antenna element or the first or second antenna feed point, such that the antenna length of either the first or second serpentine antenna element is longer than the antenna length of the second or first serpentine antenna element, respectively; an impedance-matching circuit electrically connected to one of the first and second serpentine antenna elements and configured to facilitate impedance-matching and current flow between the antenna system and the IC; and a shunt electrically connected to the first and second serpentine antenna elements and configured to facilitate impedance matching between the antenna system and the IC. - View Dependent Claims (25, 26, 27, 28)
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Specification