Passive transponder for an RFID system, and method of transmitting data from/to a data source of such a passive transponder
First Claim
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1. A passive transponder for an RFID system, comprising:
- an antenna;
an antenna oscillator circuit; and
a data source;
whereinthe antenna oscillator circuit is configured to;
operate at a first resonant frequency to store, in the antenna oscillator circuit, energy received by the passive transponder; and
operate at a second resonant frequency to generate, using only the energy stored in the antenna oscillator circuit, a data transmission signal at the second resonant frequency for a data transmission from the data source;
whereinthe antenna oscillator circuit includes a capacitive assembly and an inductive assembly;
at least one of a capacitance value of the capacitive assembly and an inductance value of the inductive assembly is variable to switch the antenna oscillator circuit from the first resonant frequency to the second resonant frequency; and
a controller is provided and programmed to change the capacitance value of the capacitive assembly if a predetermined portion of the energy stored within the antenna oscillator circuit is stored within the inductive assembly.
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Abstract
A passive transponder includes an antenna, an antenna oscillator circuit and a data source. The antenna oscillator circuit is configured to operate at a first resonant frequency or at a second resonant frequency, depending on reception of energy at the transponder or on a data transmission from/to the data source.
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Citations
12 Claims
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1. A passive transponder for an RFID system, comprising:
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an antenna; an antenna oscillator circuit; and a data source;
whereinthe antenna oscillator circuit is configured to; operate at a first resonant frequency to store, in the antenna oscillator circuit, energy received by the passive transponder; and operate at a second resonant frequency to generate, using only the energy stored in the antenna oscillator circuit, a data transmission signal at the second resonant frequency for a data transmission from the data source;
whereinthe antenna oscillator circuit includes a capacitive assembly and an inductive assembly; at least one of a capacitance value of the capacitive assembly and an inductance value of the inductive assembly is variable to switch the antenna oscillator circuit from the first resonant frequency to the second resonant frequency; and a controller is provided and programmed to change the capacitance value of the capacitive assembly if a predetermined portion of the energy stored within the antenna oscillator circuit is stored within the inductive assembly. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A transponder system comprising:
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a passive transponder for an RFID system, comprising; an antenna; an antenna oscillator circuit; and a data source;
whereinthe antenna oscillator circuit is configured to; operate at a first resonant frequency to store, in the antenna oscillator circuit, energy received by the passive transponder; and operate at a second resonant frequency to generate, using only the energy stored in the antenna oscillator circuit, a data transmission signal at the second resonant frequency for a data transmission from the data source; the antenna oscillator circuit includes a capacitive assembly and an inductive assembly; at least one of a capacitance value of the capacitive assembly and an inductance value of the inductive assembly is variable to switch the antenna oscillator circuit from the first resonant frequency to the second resonant frequency; and a controller is provided and programmed to change the capacitance value of the capacitive assembly if a predetermined portion of the energy stored within the antenna oscillator circuit is stored within the inductive assembly; and a reader configured to excite the passive transponder at the first resonant frequency and to receive the data transmission signal from the passive transponder at the second resonant frequency. - View Dependent Claims (10, 11)
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12. A method of transmitting data from a data source of a passive transponder within an RFID system, the method comprising:
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exciting the passive transponder at a first resonant frequency of an antenna oscillator circuit of the passive transponder to store, in the antenna oscillator circuit, energy received by the passive transponder; and transmitting the data by switching the first resonant frequency of the antenna oscillator circuit of the passive transponder to a second resonant frequency to generate, using only the energy stored in the antenna oscillator circuit, a data transmission signal at the second resonant frequency;
whereinthe antenna oscillator circuit includes a capacitive assembly and an inductive assembly; at least one of a capacitance value of the capacitive assembly and an inductance value of the inductive assembly is variable to switch the antenna oscillator circuit from the first resonant frequency to the second resonant frequency; and a controller is provided and programmed to change the capacitance value of the capacitive assembly if a predetermined portion of the energy stored within the antenna oscillator circuit is stored within the inductive assembly.
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Specification