Flexible Folded-Patch Antenna with Tapered Edges for Metal-Mountable UHF RFID Tag Design

A flexible folded-patch tag antenna with a compact dimension of 30 mm × 50 mm × 3.3 mm (0.092λ × 0.153λ × 0.010λ) is designed for mounting on metallic objects. It consists of a tapered patch resonator on the top, two rows of small loading patches at the middle, a ground patch at the bottom, and a loop-shaped stub on the sidewall. The tag antenna can be easily fabricated using flexible soft foam substrates that are sandwiched in between the top patch, the middle patch, and the ground. The gap of the rows of the small loading patches can be adjusted for changing and fine-tuning the resonant frequency effectively without affecting much to the antenna gain. The proposed tag antenna is working in the UHF passband and it can achieve a reasonably far read distance of approximately 17.5 m on metal.