Wideband Long Range Compact Serrated Triangular Patch-Based UHF RFID Tag for Metallic Base Environment

A folded-patch tag antenna measuring ( $53.5\times 12\times 3.3$ ) mm3 has been developed for effective operation on metallic surfaces. The antenna design features a distinctive serrated triangular patch radiator on its top layer, connected to the bottom ground plane through inductive stubs positioned at the ends. This triangular patch configuration is tailored to offer enhanced impedance matching. Furthermore, the inclusion of serrations, inductive stubs, and a thin rectangular stub on the top layer serves the dual purpose of fine-tuning the resonant frequency and reducing the overall size of the tag. The designed tag antenna works well for both ETSI and FCC bands. In practical testing scenarios in ETSI band, the designed tag antenna achieves a maximum read range of 8 meters in air and 5.1 meters when mounted on a metallic plate of size $20\times 20$ cm2. For FCC band the read range is 4.5 m in air and 3.1 m for metallic surface. The tag also exhibit 4 m (ETSI) and 2.1 m (FCC) reading ranges on curved metallic surface. Notably, the wide operational frequency range of the tag encompasses both European/Indian and U.S. RFID bands.