Small-Size Wearable High-Efficiency TAG Antenna for UHF RFID of People

Abstract

This paper introduces a small-size, low-profile wearable radiator based on the coupled patches and vertically folded patches techniques for application as a tag antenna for identification of people in the European UHF RFID band. The electric field distribution comes out dominantly from the central coupling slot, and thus the electric properties of the radiator are almost unaffected by the human body to which the antenna is intended to be attached. Accordingly, with the relative size 0.14×0.12×0.009 λ0 at 866 MHz (50×40×3.04 mm3), the antenna exhibits total efficiency better than 50%, even if it is attached directly to a person.