Patent ID: 8638196

Claim:
A data carrier for contactless communication with a base station across an electromagnetic field generated by the base station, comprising an antenna coil connected to a first coil terminal and to a second coil terminal into which a received signal can be induced when the electromagnetic field is in operation, the received signal having an unmodulated coil voltage between the first and the second coil terminal, a modulation circuit for modulating the electromagnetic field with transmission data to be communicated to the base station by occasionally reducing the unmodulated coil voltage by a modulation amplitude as a result of a modification of the resistance value of a modulation load connected at least indirectly to the first and the second coil terminal, and a coil voltage control circuit arranged for controlling the unmodulated coil voltage in response to the strength of the electromagnetic field, by decreasing the unmodulated coil voltage in response to an increase in strength of the electromagnetic field, thereby decreasing the modulation amplitude.