Alumina ceramic slot antenna for UHF RFID tag embedded in vehicles

To address the problem of metallic interferences in vehicular RFID (Radio-frequency identification) applications, this paper proposes a novel alumina ceramic slot tag antenna (ACSTA). The proposed antenna consists of a grounded thin alumina ceramic substrate and a slotted top layer rectangular patch with all four shorting edges. This structure can be equivalent to a horizontal magnetic current flow above a large ground plane, so an excellent radiation performance is achieved according to the electromagnetic image theory. Meanwhile, due to the existence of the ground plane, the influences of the interferential metallic objects behind the ground to the tag antenna impedance can be maximally reduced. This ACSTA combined with a commercial chip is fabricated and measured, and the thickness of the novel tag is only 1mm. Simulation and measurement results show that the proposed antenna has an excellent performance, and the operating frequency band of the ACSTA covers U.S. legal UHF RFID (902MHz-928MHz) band, and so it is a quite suitable candidate for vehicular RFID applications.