Design of Active RFID Reader for Fast Recognition Time

This paper proposed a transponder detection method to reduce recognition time in RFID system. It´s also shown that conventional procedure of communication in the system could cause a waste of time when a reader recognizes a transponder. The reduction of recognition time can be obtained by developing a circuit to detect a transponder actively. Detecting a transponder is achieved by using the variation of reader antenna voltage that happens when a transponder approaches to the vicinity of magnetic field formed by the reader. By adding a comparator to the antenna receiver of a reader, the reader can perceive approach or existence of a transponder. A reader for experiment is made using the MFRC500 by Phillip that supports ISO/IEC 14443 protocol. Comparing the proposed method with the conventional methods by experiment, there are 47.5 ms reduction of recognition time maximally and 12 ms in average