Antenna systems for passive RFID tags
First Claim
1. An antenna system for a radio-frequency identification (RFID) tag that includes an integrated circuit (IC), comprising:
- an antenna substrate having a proximal end arranged adjacent the IC, and a distal end;
a first serpentine antenna element formed on the antenna substrate and having a proximal end electrically connected to the IC;
a second antenna element running in the same direction from the IC as the first serpentine antenna element and having a proximal end connected to the IC, the second antenna element comprising at least one of a second serpentine antenna element formed on the antenna substrate element and a conducting wire;
a shunt electrically connected to first serpentine antenna element and to the second antenna element, the shunt configured to facilitate impedance matching between the antenna system and the IC; and
wherein, when the second antenna element comprises said second serpentine antenna element, further including an impedance-matching circuit electrically connected to at least one of the first and second serpentine antenna elements.
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.
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Citations
20 Claims
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1. 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 arranged adjacent the IC, and a distal end; a first serpentine antenna element formed on the antenna substrate and having a proximal end electrically connected to the IC; a second antenna element running in the same direction from the IC as the first serpentine antenna element and having a proximal end connected to the IC, the second antenna element comprising at least one of a second serpentine antenna element formed on the antenna substrate element and a conducting wire; a shunt electrically connected to first serpentine antenna element and to the second antenna element, the shunt configured to facilitate impedance matching between the antenna system and the IC; and wherein, when the second antenna element comprises said second serpentine antenna element, further including an impedance-matching circuit electrically connected to at least one of the first and second serpentine antenna elements. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. 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 and a distal end; first and second serpentine antenna elements each supported by the antenna substrate and each having a proximal and a distal end; first and second 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 at least one of the serpentine antenna elements and the antenna feed points, the conducting wire running in the same direction as the 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 or one of the serpentine antenna elements and the conducting wire, the shunt configured to facilitate impedance matching between the antenna system and the IC. - View Dependent Claims (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 and a distal end; first and second serpentine antenna elements supported by the antenna substrate and each having a proximal and a distal end and that run in the same direction; first and second 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; an impedance-matching circuit electrically connected to one of the first and 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 (17, 18, 19, 20)
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Specification