Miniature I-shaped Patch for Metal-mountable UHF RFID Tag Design

A novel structure consists of an I-shaped radiating patch with double T-slots is designed for ultra-high frequency (UHF) radio frequency identification (RFID) tag that can be used for mountable metal tagging. The T-slots on the radiating patch increase the electrical current path resulting in size miniaturization. The radiating patch is shorted to the ground plane using an inductive stub, where the inductive stub is useful for frequency tuning. The proposed tag is low in profile and has a compact size of 43.45 mm × 43.45, equivalent to 0.133λ ×0.133λ at 920 MHz. It provides sufficient resistance and inductive reactance for achieving conjugate impedance matching with the microchip. The proposed tag offers a good power transmission coefficient and a theoretical read range of 8.4 m with an EIPR of 4 W when mounted on a metallic surface.