RFID tag and automatic recognition system

A RFID tag and an automatic recognition system using the same are provided. Even though the RFID tag is small, the communication distance can be ensured. The RFID tag has heat resistance, and is cost-effective compared with the conventional RFID tags. The RFID tag includes a substrate made of resin, an IC chip disposed on the central part of the substrate, a single layer antenna disposed on the outer periphery of the IC chip and connected to the IC chip to form a closed electrical circuit, and a sealing member for sealing the IC chip and the antenna, wherein the antenna is a coil antenna or a loop antenna. The resonant frequency f0 of the electrical circuit formed by including the inductance L of the antenna and the capacitance C of the IC chip is at or near the operating frequency of the IC chip. The operating frequency of the IC chip is from 13.56 MHz to 2.45 GHz, or from 0.86 to 0.96 GHz. The size of the RFID tag is longitudinal of 13 mm or less * horizontal of 13 mm or less *height of 1.0 mm or less. The