Wearable UHF RFID Tag Antenna Design using Hilbert Fractal Structure

Abstract

A broadband ultra-high frequency (UHF) radio frequency identification tag antenna is proposed for wearable applications. The antenna consists of an elliptical matching loop and capacitive loading plates to reduce the size of the antenna. This tag was printed on a low-cost 0.5 mm paper substrate. We employ a first order Hilbert fractal structure and parallel strips to further improve impedance. The Hilbert fractal structure was etched on the capacitive loading. The proposed tag antenna offers broadband characteristics (ranging from 860 MHz to 960 MHz), when attached to the multi-layered human model. Moreover, the tag antenna can able to work with metallic objects, if one end loading plate of the antenna is attached to metal. Furthermore, the designed tag provides a read range of 5.5 m and 8.5 m, when attached to the human body and the metal plate (100×100mm2), respectively.