Compact on-Metal UHF RFID Tag Antenna

This study investigates the design and development of a compact UHF RFID tag antenna for on-metal applications. Typical UHF RFID tag antennas face limitations when placed near metallic objects, as the metal can reduce the tag's realized gain and read distance. To address this, a slotted structure is introduced in the patch design, enabling the UHF RFID tag to function efficiently even when attached to metal surfaces. The proposed tag antenna has a compact size of 48 mm by 48 mm and is mounted on a 200 mm by 200 mm metal plate. It is designed on a polyethylene terephthalate (PET) substrate with a thickness of 0.05 mm and a dielectric constant of 3.4. The radiating patch is connected to the ground plane via an inductive stub and operates within the UHF RFID band (860–960 MHz), resonating at 916.4 MHz. The proposed tag antenna achieves a far-read distance of approximately 5 meters. All simulation and optimization procedures were conducted using CST Microwave Studio software.