Radiation efficiency improvement method of RFID tag antenna for metallic objects printed on lossy substrate

This paper proposes a novel design method of RFID tag antenna on metallic surfaces using a lossy substrate such as FR4. The proposed design reduces the substrate loss and improves the radiation efficiency more than double compared with a conventional PIFA (planar inverted-F antenna). The antenna can be directly matched to the typical high-Q impedance of a tag chip, which consists of small resistance and large capacitive reactance.