Chipless RFID tag at 13.56MHz

In contrast to EAS (electronic article surveilance) systems, RFID is expected to carry a digital code as article identity information.
A digital memory - or in other words a chip - is required to store it and encode it to the RF signal.

About chipless EAS systems, see:
https://www.edaboard.com/viewtopic.php?t=344733 or
http://en.wikipedia.org/wiki/Electro...e_surveillance

Chipless RFID-Tags are possible. They working with the SAW principle.
http://www.rfidjournal.com/glossary/148
SAW Tags for UHF RFID exsist, but I don't know about LF-Tags

The low available bandwidth of 13.56 MHz systems involves a respective time duration of a modulated signal, that carries more
information than yes or no. In my opinion, it can't be handled by reasonable dimensioned SAW components.