On the Use of Knitted Antennas and Inductively Coupled RFID Tags for Wearable Applications

Abstract

Recent advancements in conductive yarns and fabrication technologies offer exciting opportunities to design and knit seamless garments equipped with sensors for biomedical applications. In this paper, we discuss the design and application of a wearable strain sensor, which can be used for biomedical monitoring such as contraction, respiration, or limb movements. The system takes advantage of the intensity variations of the backscattered power (RSSI) from an inductively-coupled RFID tag under physical stretching. First, we describe the antenna design along with the modeling of the sheet impedance, which characterizes the conductive textile. Experimental results with custom fabricated prototypes showed good agreement with the numerical simulation of input impedance and radiation pattern. Finally, the wearable sensor has been applied for infant breathing monitoring using a medical programmable mannequin. A machine learning technique has been developed and applied to post-process the RSSI data, and the results show that breathing and non-breathing patterns can be successfully classified.

Monitoring vital signs over multiplexed radio by near-field coherent sensing

“…We chose to implement NCS by passive harmonic RF identification (RFID) tags 21 , where the vital signals are modulated on the harmonic backscattering together with the tag ID. Besides the ultralow cost, the simple and robust packaging of the passive tag enables direct fabric integration with laundry readiness 22,23 . An example of the RFID sensor tag chip integrated with an embroidered antenna on fabric is shown in Supplementary Fig.…”

3D-Printed Graphene Antennas and Interconnections for Textile RFID Tags: Fabrication and Reliability towards Humidity

“…Graphene ink can be used as a conductor in these printed structures, which opens novel possibilities for textile antenna and antenna-electronics interconnection fabrication. In particular, passive RFID (radio-frequency identification) tags integrated into textiles, which will be the focus of this paper, provide versatile wireless identification and sensing possibilities embedded into clothing [4][5][6][7] and are thus a great platform for this new fabrication method and material. In wearable systems, textile antennas can be used in a great variation of applications [8] and often they operate in an extremely challenging environment.…”

Wearable Hardware Design for the Internet of Medical Things (IoMT)

“…That being said, they are releasing their next generation with functional fabrics. They have incorporated physiological sensors into their garments using advanced knitting techniques, and are now moving towards the introduction of Radio-Frequency Identification technology (RFID) [ 49 ]. It has been proven recently that the use of RFID technology for traditional metal-based tags allows for the capture of material deformations.…”