Chipless RFID system based on magnetoinductive-wave (MIW) delay lines

A novel fully passive and electromagnetic chipless radiofrequency identification (RFID) system is proposed. The system is based on printed tags implemented with magnetoinductive-wave (MIW) delay lines. Such lines are composed of a periodic chain of magnetically coupled resonators and propagate slow waves. The identification (ID) code is implemented by introducing reflectors between the elements of the MIW line. When the tags are interrogated with a pulse in time domain, they produce replicas at the positions where the reflectors are placed. Thanks to the slow group velocity of the MIW delay line, the replicas of the original pulse are not overlapped in time domain and can be demodulated, thus providing the ID code of the tag.