Method and apparatus for multiple frequency RFID tag architecture
First Claim
1. An antenna structure for a RFID tag interrogatable by at least one reader, comprising:
- a first antenna portion, comprising first and second electrostatic elements, that is responsive to an electrostatic interrogation signal at at least one first frequency; and
a second antenna portion, comprising first and second electromagnetic elements, that is responsive to a far-field electromagnetic signal at at least one second frequency,wherein the first electrostatic element comprises a first non-resonant plate and the first electromagnetic element, and the second electrostatic element comprises a second non-resonant plate and the second electromagnetic element.
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Accused Products
Abstract
The present invention provides a multi-band, multi-mode RFID tag that uses a single antenna structure and integrated circuit to provide asset location information at any stage of a supply chain. The unified tag design operates at multiple frequencies (or bands) using the antenna structure, for example, 125 kHz, 13.56 MHz, 915 MHz, and 2.45 GHz, and preferably operates electrostatically (at lower frequencies) and electromagnetically (ay higher frequencies). An on-chip frequency monitor in the integrated circuit automatically determines which frequency is present and derives a local clock for the tag'"'"'s integrated circuit, which can vary in accordance with the frequency or which can be constant. Alternatively, a phase locked loop circuit can be used to derive a local clock signal modulated into the interrogation signal. On-chip matching and power extraction circuits derive power for the tag from the interrogation signal, which is preferably passive. Additionally, a receiver can receive data from the interrogation signal.
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Citations
27 Claims
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1. An antenna structure for a RFID tag interrogatable by at least one reader, comprising:
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a first antenna portion, comprising first and second electrostatic elements, that is responsive to an electrostatic interrogation signal at at least one first frequency; and a second antenna portion, comprising first and second electromagnetic elements, that is responsive to a far-field electromagnetic signal at at least one second frequency, wherein the first electrostatic element comprises a first non-resonant plate and the first electromagnetic element, and the second electrostatic element comprises a second non-resonant plate and the second electromagnetic element. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A RFID tag interrogatable by at least one reader, comprising:
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an antenna structure on a substrate, comprising a first antenna portion, comprising first and second electrostatic elements, that is responsive to an electrostatic interrogation signal at at least one first frequency; and a second antenna portion, comprising first and second electromagnetic elements, that is responsive to a far-field electromagnetic signal at at least one second frequency, wherein the first electrostatic element comprises a first non-resonant plate and the first electromagnetic element, and the second electrostatic element comprises a second non-resonant plate and the second electromagnetic element; and an integrated circuit mounted to the substrate and coupled to the antenna for providing data from the tag to the reader in response to either the electrostatic or far-field electromagnetic interrogation. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27)
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Specification