FDTD Analysis of Electromagnetic Wave Propagation for Out-door Active RFID System

In recent years, RFID systems have received much attention in security, logistics and medical fields. However, most of these systems axe used at in-door and the RF tags axe passive tags that are controlled by reader. We consider to use active RFID system of very weak UHF electromagnetic waves at out-door. In this paper, we describe the characteristics of electromagnetic wave propagation by RF tags using FDTD method. In transmit and receive points of the weak electromagnetic wave, receive characteristics axe influenced by the established environment. We consider the road models as this environment. RF tags axe carried by the human on the road, and the readers are installed on the electric pole and connected to the cable network. As out-door models, we consider road models of three types, the straight road, the T-type road and the cross road and numerical results of maximum receiving intensity of the electric fields in these models axe shown.