ULTRA LOW FREQUENCY CONTACTLESS SMART CARDS
D. Ciudad – L. Pérez – P. Sánchez – M. C. Sánchez – E. López – C. Aroca
A new contactless system that can work at ultralow frequencies (<100 kHz, 2 kHz used) has been developed. At this frequencies the screening problems of the current technologies are avoided. It is characterized by the use of a tunable magnetic sensor; concretely, a fluxgate with a double demodulation technique, as detection module. The main difference with the commercial systems used at present is that it is based on the detection of the magnetic field produced by the card, not on an inductive coupling. Due to the incorporation of a magnetic core, the card does not need a resonant circuit.
Keywords: contactless, smart card, RFID, double demodulation, fluxgate, tunable sensor, magnetic core