A Compact Wearable UHF RFID Textile Tag Antenna with Hybrid Meandered-Line and Loop Geometry

This paper presents the design, fabrication, and experimental validation of a compact wearable UHF RFID tag integrated onto a superhydrophobic textile substrate for industrial worker identification and tracking. The proposed antenna combines a meander-line structure with a rectangular loop to achieve a small form factor while maintaining robust electromagnetic performance. Electromagnetic simulations demonstrate that the antenna exhibits an input impedance of 34 + j 205 Ω at 868 MHz, closely matching the complex conjugate of the Alien Higgs-3 microchip, and achieves a gain of 1.75 dBi with a directivity of 1.9 dBi. Fabrication was performed using inkjet printing with conductive inks, and the microchip was mounted with a conductive adhesive. Experimental measurements confirm a read range of approximately 4 m under a standard test setup, in good agreement with theoretical predictions. The proposed design demonstrates high reliability, flexibility, and washability, making it suitable for integration into personal protective equipment (PPE) for real-time worker monitoring in industrial environments.