Device and method for the simultaneous reading of passive inductive transponders
First Claim
1. Transponder reading device for reading out a plurality of inductive passive transponders having a resonant circuit, the device comprising:
- a transmitter coil for generating an alternating magnetic field having an operating frequency fB, in which the plurality of transponders may be placed such that they are magnetically coupled to each other; and
a retuning circuit arranged in the alternating magnetic field and having such a frequency-dependent impedance that a voltage induced in the resonant circuits of the transponders by the alternating magnetic field has a maximum in the range of the operating frequency fB.
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Accused Products
Abstract
The present invention relates to a transponder reading device for reading out a plurality of inductive passive transponders (50) having a resonant circuit. A transmitter coil (62) is provided to create an alternating magnetic field having an operating frequency fB, in which the number of transponders (50) may be placed such that same are magnetically coupled to each other. A retuning means (56) is further provided which is arranged in the alternating magnetic field and has such a frequency-dependent impedance that a voltage induced in the resonant circuits of the transponders (50) by the alternating magnetic field has a maximum in the range of the operating frequency fB.
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Citations
10 Claims
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1. Transponder reading device for reading out a plurality of inductive passive transponders having a resonant circuit, the device comprising:
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a transmitter coil for generating an alternating magnetic field having an operating frequency fB, in which the plurality of transponders may be placed such that they are magnetically coupled to each other; and
a retuning circuit arranged in the alternating magnetic field and having such a frequency-dependent impedance that a voltage induced in the resonant circuits of the transponders by the alternating magnetic field has a maximum in the range of the operating frequency fB. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. Method for reading out a plurality of inductive passive transponders having a resonant circuit, the method comprising:
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generating an alternating magnetic field having an operating frequency fB;
placing the plurality of transponders in the alternating magnetic field such that the transponders are magnetically coupled to each other;
placing a retuning circuit in the alternating magnetic field, the retuning circuit having such a frequency-dependent impedance that a voltage induced in the resonant circuits of the transponders by the alternating magnetic field has a maximum in the range of the operating frequency fB; and
receiving data created by the transponders in response to the voltage induced. - View Dependent Claims (9)
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10. Transponder having a resonant circuit consisting of a transponder coil and a tuning capacitor, the resonant circuit being tuned such that a lower minimum cut-off frequency fu,min is in the range of a preset operating frequency fB of an alternating magnetic field, the lower minimum cut-off frequency fu,min being the frequency approached by the lowest-frequency maximum of the voltage induced in the transponder resonant circuit by the alternating magnetic field of the operating frequency fB if a theoretically unlimited number of transponders are arranged in the alternating magnetic field.
Specification