Passive UHF RFID Yarn For Temperature Sensing Applications

This paper presents an Ultra High Frequency (UHF) Radio Frequency IDentification (RFID) temperature sensor integrated into a textile yarn. The tag system consists of a thermistor of which the resistance is sensitive to temperature variation. The theoretical working principle is detailed and validated using electromagnetic simulation. The UHF RFID temperature sensor is fabricated using the E-Thread® technology. Experimental results demonstrate the potential of the sensor for detecting a temperature variation comprised between $25^{\circ}\mathrm{C}$ and $70^{\circ}\mathrm{C}$ through a variation of the reading distance between 4.5 meters to 6.2 meters.

I. Introduction

The Radio Frequency Identification (RFID) technology became ubiquitous in our everyday life [1]. RFID is used in a wide range of applications such as logistics, access control and ID cards. Passive RFID systems consist on a communication between two elements: a reader and a passive tag by using the backscattering technique [2].