RFID tag antenna using two‐shorted microstrip patches mountable on metallic objects

A novel UHF band RFID tag antenna, which can be effectively mounted on metallic objects, is presented. Using the inductively coupled feeding technique, the proposed antenna consists of two symmetric shorted radiating elements and feeding loop. The feeding loop is excited so that the currents on the radiating elements are out of phase with the equal amplitude. The proposed tag antenna gives smaller variation of the antenna performance than that of conventional tag antennas when the tag is mounted on the various sizes of the metallic objects.