Miniature slotted RFID tag antenna for metallic objects

Designing RFID tag antenna for metallic objects is a challenging task as antenna parameters are highly affected by metallic surface. This paper presents a miniaturized slotted RFID tag antenna with overall dimensions of 33 mm × 16 mm × 3.2 mm for metallic objects. The proposed design contains two coplanar metallic patches which are electrically connected to the ground plane through a copper via. Multiple slots are created on metallic patches which help in improving overall antenna inductance. A non-connected metallic plate is present between the ground and the patches. The proposed antenna design is simulated and fabricated, and its parameters are analyzed. It is concluded that this design can be reused for different tag chips having different input impedances simply by varying slot length without changing any other antenna dimensions. The read range of the proposed design, when the tag antenna is mounted on the metallic surface, is approximately 80 cm.