Passive RFID sensor tag and RFID reader
First Claim
1. A method for interrogating a sensor value in a system having a radio frequency identification (RFID) reader and at least one passive RFID sensor tag for communication with a backscattering principle, wherein a modulated backscattered signal carrying a digital response comprises sidebands that are offset from an interrogation frequency by a modulation signal, the method comprising on the RFID reader side of the system:
- sending a radio frequency interrogation signal from the RFID reader over a radio path to the at least one passive RFID sensor tag, the at least one passive RFID tag having;
(i) an antenna configured to receive the radio frequency interrogation signal such that the at least one passive RFID tag is powered by the radio frequency interrogation signal, (ii) an oscillator configured to output a modulation frequency to modulate a backscattered radio frequency signal that is sent from the at least one passive RFID tag through the antenna and the radio path back to the RFID reader, and (iii) a sensing element connected to operate as part of the oscillator to sense a quantity separate of the radio frequency interrogation signal and to apply a value to the sensed quantity such that the modulation frequency is dependent on the value of the sensed quantity;
receiving, at the RFID reader over the radio path from the at least one passive RFID tag, the backscattered radio frequency signal modulated with the oscillation frequency, wherein the offset of the sidebands of the modulated backscattered signal carrying the digital response is arranged to be dependent on and carry the value of the sensed quantity;
identifying the at least one passive RFID tag;
converting the modulation frequency of the backscattered signal into an actual value of the sensed quantity based on predetermined sensor configuration information of the identified passive RFID sensor tag, the sensor configuration information including information on a sensor element or sensor elements available in the identified passive RFID sensor tag, and particularly for each available sensor element information how to convert the modulation frequency of the backscattered signal into actual values of the quantity sensed by the respective sensing element.
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Accused Products
Abstract
An RFID system includes a radio frequency identification (RFID) reader and at least one passive RFID sensor tag. A backscattered radio frequency signal from the passive RFID tag is modulated with an oscillation frequency which is dependent on a value of a quantity sensed by a sensing element. The RFID reader converts converting the oscillation frequency of the backscattered signal into an actual value of the sensed quantity based on predetermined sensor configuration information of the passive RFID sensor tag. The sensor configuration information includes information on a sensor element or sensor elements available in the passive RFID sensor tag, and particularly information how to convert the oscillation frequency of the backscattered signal into actual values of the quantity sensed by the respective sensing element.
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Citations
18 Claims
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1. A method for interrogating a sensor value in a system having a radio frequency identification (RFID) reader and at least one passive RFID sensor tag for communication with a backscattering principle, wherein a modulated backscattered signal carrying a digital response comprises sidebands that are offset from an interrogation frequency by a modulation signal, the method comprising on the RFID reader side of the system:
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sending a radio frequency interrogation signal from the RFID reader over a radio path to the at least one passive RFID sensor tag, the at least one passive RFID tag having;
(i) an antenna configured to receive the radio frequency interrogation signal such that the at least one passive RFID tag is powered by the radio frequency interrogation signal, (ii) an oscillator configured to output a modulation frequency to modulate a backscattered radio frequency signal that is sent from the at least one passive RFID tag through the antenna and the radio path back to the RFID reader, and (iii) a sensing element connected to operate as part of the oscillator to sense a quantity separate of the radio frequency interrogation signal and to apply a value to the sensed quantity such that the modulation frequency is dependent on the value of the sensed quantity;receiving, at the RFID reader over the radio path from the at least one passive RFID tag, the backscattered radio frequency signal modulated with the oscillation frequency, wherein the offset of the sidebands of the modulated backscattered signal carrying the digital response is arranged to be dependent on and carry the value of the sensed quantity; identifying the at least one passive RFID tag; converting the modulation frequency of the backscattered signal into an actual value of the sensed quantity based on predetermined sensor configuration information of the identified passive RFID sensor tag, the sensor configuration information including information on a sensor element or sensor elements available in the identified passive RFID sensor tag, and particularly for each available sensor element information how to convert the modulation frequency of the backscattered signal into actual values of the quantity sensed by the respective sensing element. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. An RFID reader comprising
a sender and a receiver arranged to communicate with at least one passive RFID sensor tag for communication with a backscattering principle, the sender being configured to send a radio frequency interrogation signal from the RFID reader over a radio path to the at least one passive RFID sensor tag, the at least one passive RFID tag having an antenna configured to receive the radio frequency interrogation signal such that the at least one passive RFID tag is powered by the radio frequency interrogation signal, an oscillator configured to output a modulation frequency to modulate a backscattered radio frequency signal that is sent from the at least one RFID tag through the antenna and the radio path back to the RFID reader, and a sensing element connected to operate as part of the oscillator to sense a quantity separate of the radio frequency interrogation signal and to apply a value to the sensed quantity such that the modulation frequency is dependent on the value of the sensed quantity; -
the receiver receiving, at the RFID reader over the radio path from the at least one passive RFID tag, the backscattered radio frequency signal which carries a digital response and comprises sidebands that are offset from an interrogation frequency by the modulation frequency, wherein the offset of the sidebands of the modulated backscattered signal is dependent on and carry the value of the sensed quantity; a controller identifying the at least one passive RFID tag; and a converter converting the modulation frequency of the backscattered signal into an actual value of the sensed quantity based on predetermined sensor configuration information of the identified passive RFID sensor tag, the sensor configuration information including information on a sensor element or sensor elements available in the identified passive RFID sensor tag, and particularly for each available sensor element information how to convert the modulation frequency of the backscattered signal into actual values of the quantity sensed by the respective sensing element. - View Dependent Claims (16)
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17. A passive RFID sensor tag comprising:
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an antenna configured to receive a radio frequency interrogation signal such that the passive RFID sensor tag is powered by the radio frequency interrogation signal; an oscillator configured to output a modulation frequency to modulate a backscattered radio frequency signal that is sent from the passive RFID sensor tag through the antenna and a radio path back to the RFID reader; a sensing element connected to operate as part of the oscillator to sense a quantity separate of the radio frequency interrogation signal and to apply a value to the sensed quantity such that the modulation frequency is dependent on the value of the sensed quantity; and a memory storing predetermined sensor configuration information, the sensor configuration information including one or more of information on the at least one sensor element available in the passive RFID sensor tag, and information for each available sensor element how the modulation frequency depend on actual values of the quantity sensed by the respective sensing element.
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18. A network element system comprising:
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at least one RFID reader arranged to communicate with at least one passive RFID sensor tag over a radio path and with a backscattering principle, wherein a modulated backscattered signal carrying a digital response includes sidebands that are offset from an interrogation frequency by a modulation frequency, and the at least one passive RFID sensor tag includes (i) an antenna configured to receive a radio frequency interrogation signal such that the at least one passive RFID tag is powered by the radio frequency interrogation signal, (ii) an oscillator configured to output a modulation frequency to modulate the backscattered radio frequency signal that is sent from the at least one passive RFID tag through the antenna and the radio path back to the RFID reader, and (iii) a sensing element connected to operate as part of the oscillator to sense a quantity separate of the radio frequency interrogation signal and to apply a value to the sensed quantity such that the modulation frequency is dependent on the value of the sensed quantity; and for a memory configured to permanently or temporally store sensor configuration information for the at least one passive RFID sensor tag, the sensor configuration information including one or more of information on the at least one sensor element available in the at least one passive RFID sensor tag, and information for each available sensor element how the modulation frequency depend on actual values of the quantity sensed by the respective sensing element.
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Specification