Compact and small size antenna for an UHF RFID tag placed over a metallic thing

We report in this paper the design of a compact and small size patch antenna for a RFID tag in American UHF band. The size of the proposed antenna is 91 × 36 × 6.34 mm
³
. The antenna presents good performances. A good matching of -22 dB and a high gain of 4.7 dBi are achieved at the resonant frequency (918 MHz). The proposed antenna is well adapted for a compact and small size RFID tag placed over a metallic thing.