Power management of transponders and sensors in an RFID security network
First Claim
1. An RFID transponder having an associated sensor and being configured for use in a security network including at least a first RFID reader that transmits signals at a first frequency, the RFID transponder comprising:
- a processor controlling other components of the RFID transponder;
transmitter circuitry coupled to a transmit antenna for transmitting signals to the first RFID reader at a second frequency;
a receive antenna receiving signals in a frequency band that includes the first frequency;
at least one RF diode obtaining the signal from the receive antenna and configured to output a power envelope signal representing the power level of the signal obtained from the receive antenna; and
an amplifier coupled to the output of the RF diode and amplifying the power envelope signal received from the RF diode;
wherein the processor receives the amplified power envelope signal and decodes any data that have been encoded using an on-off keyed modulation scheme applied to the signal obtained from the receive antenna.
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Accused Products
Abstract
An RFID transponder with an associated sensor used in a security network including at least one RFID reader that transmits signals at a first frequency. The transponder has a processor controlling its other components. Transmitter circuitry coupled to a transmit antenna transmits signals to the reader at a second frequency. A receive antenna receives signals in a frequency band that includes the first frequency. One or more RF diodes obtain the signal from the receive antenna and output a power envelope signal representing the power level of the signal obtained from the receive antenna. An amplifier coupled to the output of the RF diode amplifies the power envelope signal received from the RF diode. The processor receives the amplified power envelope signal and decodes any data that have been encoded using an on-off keyed modulation scheme applied to the signal obtained from the receive antenna.
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Citations
33 Claims
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1. An RFID transponder having an associated sensor and being configured for use in a security network including at least a first RFID reader that transmits signals at a first frequency, the RFID transponder comprising:
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a processor controlling other components of the RFID transponder;
transmitter circuitry coupled to a transmit antenna for transmitting signals to the first RFID reader at a second frequency;
a receive antenna receiving signals in a frequency band that includes the first frequency;
at least one RF diode obtaining the signal from the receive antenna and configured to output a power envelope signal representing the power level of the signal obtained from the receive antenna; and
an amplifier coupled to the output of the RF diode and amplifying the power envelope signal received from the RF diode;
wherein the processor receives the amplified power envelope signal and decodes any data that have been encoded using an on-off keyed modulation scheme applied to the signal obtained from the receive antenna. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method for managing the power of an RFID transponder having an associated sensor and being configured for use in a security network including at least a first RFID reader, the method comprising:
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(a) sending signals from the RFID transponder to the first RFID reader at a second frequency representing relatively low power;
(b) transmitting return signals from the first RFID reader at a first frequency representing relatively high power;
(c) receiving the return signals at at least one diode of the RFID transponder; and
(d) applying at least one of an on-off keyed modulation and an amplitude modulation scheme to the signal obtained by the diode. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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33. A security network comprising:
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at least a first RFID reader transmitting signals at a first frequency and including;
(a) a first diversity antenna sending a first message, (b) a second diversity antenna sending a second message, and (c) a receiver; and
an RFID transponder having an associated sensor, the RFID transponder including;
(a) a processor controlling other components of the RFID transponder, (b) transmitter circuitry coupled to a transmit antenna for transmitting signals to the first RFID reader at a second frequency, (c) a receive antenna receiving signals in a frequency band that includes the first frequency, (d) at least one RF diode obtaining the signal from the receive antenna and configured to output a power envelope signal representing the power level of the signal obtained from the receive antenna, and (e) an amplifier coupled to the output of the RF diode and amplifying the power envelope signal received from the RF diode;
wherein the processor receives the amplified power envelope signal and decodes any data that have been encoded using an on-off keyed modulation scheme applied to the signal obtained from the receive antenna.
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Specification