A PORTABLE CARD WITH AN RFID COIL

摘要

An RFID-type system is described in which a portable card receives a signal from a transceiver and outputs a phase modulated or amplitude modulated signal from which the transceiver derives information transmitted from the card. Alternatively, the card may have a coil with a self inductance of 3mH or more which, by altering the characteristics ofthe coil or a circuit connected thereto (loading the coil) facilitates a loading of the signal from the transceiver, which load change may be used for extracting the additional information.