Tag movement direction estimation methods in an RFID gate system

An RFID system using many RF tags has some advantages over a bar code system such as simultaneous multi-reading and long read range. Especially, it has been strongly desired by logistics and the retail industry for efficiency of operation. Recently, user-friendly RFID systems are being studied. We focused on a gate system using RFID technologies. It will be very useful for the efficiency of inventory management and the check of illicit smuggling out. In this paper, a new method of tag movement direction detection using the difference of passing time of two antennas without external expensive sensors is proposed. Some experimental results of this method are also shown and its feasibility is proved.