Ceramic patch antenna for UHF RFID tag embedded in metallic objects

A design for tag antenna(diameter of 34 mm) using ceramic material and PIFAs at UHF band, embedded in metallic object is implemented. The antenna can be directly matched to the arbitrary reactance of a tag chip. The proposed tag antenna also has good characteristics of the radiation patterns and the high restraining cross polarization level. It is verified that the proposed tag has good performance by measuring the reading distance over 3m when the tag is just embedded in metallic object.