Device for contactless transmission of data
AssigneeInfineon Technologies AG
InventorsLorenz Gaul, Martin Häring
Life of this patent
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Abstract
A device for a contactless transmission of data includes a data transceiver with an antenna. The impedance of the antenna of the data transceiver is purposely mismatched. A reactance is introduced into the antenna in order to tune the antenna to a frequency different from its resonant frequency. In the event that the antenna impedance has to be adapted to the characteristic impedance of a line of unknown length, the loss resistance of the antenna is deliberately increased. The power required to produce a magnetic alternating field with the data transceiver for operating at least one portable data carrier is reduced.
Claims9
A device for a contactless transmission of data, comprising:
- a data transceiver and a portable data carrier;
- said data transceiver including:
- a transmitting device for producing a first signal of a given frequency;
- a receiving device for receiving a second signal of a given frequency;
- a line of unknown length, said line having a characteristic impedance;
- a data transceiver antenna connected to said transmitting device and to said receiving device via said line of unknown length;
- a matching circuit configuration connected between said data transceiver antenna and at least one of said transmitting device and said receiving device, said matching circuit configuration having at least one resistance limiting a factor Q for matching a total impedance to the characteristic impedance of said line, and said matching circuit having an additional loss resistance;
- said portable data carrier including:
- a data carrier antenna for transmitting and for receiving an induced signal;
- and
- a circuit configuration, connected to said data carrier antenna, for processing the induced signal and for producing a signal to be transmitted to said data transceiver antenna.
Dependencies are inferred from the claim text.