SYSTEM AND METHOD FOR DATA COLLECTION USING NEAR-FIELD MAGNETIC INDUCTION
First Claim
1. A system for collecting data about objects moving within a specified site:
- at least one tag reader disposed within a specified site and configured to transmit a magnetic field to an interrogation area within the specified location and extending at least two meters across an open-air gap, the at least one tag reader having a transceiver antenna comprising;
a first antenna coil disposed on a planar substrate and substantially defining a first coil closed geometry with an innermost first coil turn and an outermost first coil turn;
at least one second antenna coil disposed on the planar substrate within the innermost first coil turn and having a plurality of second coil turns each defining a substantially closed second coil geometry, wherein the at least one second antenna coil defines an effective second coil area; and
at least one third antenna coil disposed on the planar substrate outside of the outermost first coil turn and having a plurality of third coil turns defining a substantially closed third coil geometry, wherein the at least one third antenna coil has an effective third antenna coil area;
wherein the at least one third antenna coil is connected in series with the at least one second antenna coil and wherein the effective third antenna coil area differs from the effective second coil area by no more than 5%, thereby resulting in at least 95% phase cancellation between a second voltage induced in the at least one second antenna coil and a third voltage induced in the at least one third antenna coil when conducting a current through the first antenna coil; and
a plurality of tags configured to wirelessly communicate with the at least one tag reader via near-field magnetic induction across an open air gap of at least 2 meters, wherein each of the plurality of tags is constructed to be carried by an object moving within the specified site, wherein when located within the interrogation area, each of the plurality of tags is configured to wirelessly communicate a unique identifier to the at least one tag reader via near-field magnetic induction.
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Accused Products
Abstract
A method of collecting location data from objects moving within a specified site includes providing at least one tag reader and a plurality of tags each configured to communicate via near-field magnetic induction across an open-air gap of at least two meters. The tag reader listens for a tag signal transmitted by any one or more of the tags. Each tag transmits a tag signal containing a unique identifier that is received at a tag reader. The tag signal is demodulated to determine the unique identifier associated with the particular tag. Also disclosed is a system for monitoring a condition within a shielded environment using a tag and a tag reader that communicate using near-field magnetic induction.
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Citations
19 Claims
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1. A system for collecting data about objects moving within a specified site:
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at least one tag reader disposed within a specified site and configured to transmit a magnetic field to an interrogation area within the specified location and extending at least two meters across an open-air gap, the at least one tag reader having a transceiver antenna comprising; a first antenna coil disposed on a planar substrate and substantially defining a first coil closed geometry with an innermost first coil turn and an outermost first coil turn; at least one second antenna coil disposed on the planar substrate within the innermost first coil turn and having a plurality of second coil turns each defining a substantially closed second coil geometry, wherein the at least one second antenna coil defines an effective second coil area; and at least one third antenna coil disposed on the planar substrate outside of the outermost first coil turn and having a plurality of third coil turns defining a substantially closed third coil geometry, wherein the at least one third antenna coil has an effective third antenna coil area; wherein the at least one third antenna coil is connected in series with the at least one second antenna coil and wherein the effective third antenna coil area differs from the effective second coil area by no more than 5%, thereby resulting in at least 95% phase cancellation between a second voltage induced in the at least one second antenna coil and a third voltage induced in the at least one third antenna coil when conducting a current through the first antenna coil; and a plurality of tags configured to wirelessly communicate with the at least one tag reader via near-field magnetic induction across an open air gap of at least 2 meters, wherein each of the plurality of tags is constructed to be carried by an object moving within the specified site, wherein when located within the interrogation area, each of the plurality of tags is configured to wirelessly communicate a unique identifier to the at least one tag reader via near-field magnetic induction. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of collecting location data from objects moving within a specified site comprising:
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providing at least one tag reader with a tag reader antenna configured to receive signals via near-field magnetic induction across an open-air gap of at least two meters; providing a plurality of tags configured to wirelessly communicate with the at least one tag reader via near-field magnetic induction across an open air gap of at least 2 meters; the at least one tag reader listening for the tag signal transmitted by any one or more of the plurality of tags; each of the plurality of tags transmitting a tag signal containing a unique identifier; receiving a tag signal from a particular tag at the at least one tag reader; demodulating the tag signal from the particular tag to determine the unique identifier associated with the particular tag; and saving the unique identifier. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16)
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17. A method of monitoring an enclosed environment comprising:
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disposing a sensor inside an environment enclosed by an enclosure made of metal; disposing a transmitter inside the environment, the transmitter configured to communicate using near-field magnetic induction; coupling the sensor to the transmitter; disposing a receiver outside the enclosure, the receiver configured to communicate with the transmitter using near-field magnetic induction; coupling the receiver to a communications device; wirelessly communicating a sensed condition of the environment from the transmitter to the receiver using near-field magnetic induction; and communicating the sensed condition to a user using the communications device. - View Dependent Claims (18, 19)
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Specification