Han He

The possibilities of passive UHF RFID textile tags as comfortable wearable sweat rate sensors

Sweat rate measurements can be used for healthcare purposes as well as for helping in exercising. In this paper, the suitability of passive UHF (ultra high frequency) RFID (radiofrequency identification) technology for sweat rate sensing is investigated. The technology has a great potential in wearable, comfortable, and wireless sweat sensing systems, although it is not originally used for sensing purposes. Two types of textile sensing tag prototypes are presented, their performance is evaluated by wireless measurements, and the prospects and concerns of these are discussed in this paper. The achieved results indicate high potential of textile RFID tags in perspiration sensing.

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

We present the possibilities of 3D direct-write dispensing in the fabrication of passive UHF RFID graphene tags on a textile substrate. In our method, the graphene tag antenna is deposited directly on top of the IC strap, in order to simplify the manufacturing process by removing one step, that is, the IC attachment with conductive glue. Our wireless measurement results confirm that graphene RFID tags with printed antenna-IC interconnections achieve peak read ranges of 5.2 meters, which makes them comparable to graphene tags with epoxy-glued ICs. After keeping the tags in high humidity, the read ranges of the tags with epoxy-glued and printed antenna-IC interconnections decrease 0.8 meters and 0.5 meters, respectively. However, after drying, the performance of both types of tags returns back to normal.

Experimental Study on Inkjet-Printed Passive UHF RFID Tags on Versatile Paper-Based Substrates

We present the possibilities and challenges of passive UHF RFID tag antennas manufactured by inkjet printing silver nanoparticle ink on versatile paper-based substrates. The most efficient manufacturing parameters, such as the pattern resolution, were determined and the optimal number of printed layers was evaluated for each substrate material. Next, inkjet-printed passive UHF RFID tags were fabricated on each substrate with the optimized parameters and number of layers. According to our measurements, the tags on different paper substrates showed peak read ranges of 4–6.5 meters and the tags on different cardboard substrates exhibited peak read ranges of 2–6 meters. Based on their wireless performance, these inkjet-printed paper-based passive UHF RFID tags are sufficient for many future wireless applications and comparable to tags fabricated on more traditional substrates, such as polyimide.

3D Printed and Photonically Cured Graphene UHF RFID Tags on Textile, Wood, and Cardboard Substrates

This paper introduces 3D direct writing and microdispensing of graphene ultrahigh frequency (UHF) radio-frequency-identification (RFID) antennas on textile, wood, and cardboard substrates, subsequently cured either by conventional oven or photonically by pulsed Xenon flashes. Photonic-cured passive UHF RFID graphene tags on cardboard, wood, and textile substrates achieve read ranges of 5.4, 4.6, and 4 meters, respectively. These results are superior to those achieved by the oven-cured tags that featured read ranges of 4.8, 4.5, and 3.6 meters, respectively. This work presents the first integration of 3D printing and photonic curing of graphene antennas on low-cost versatile substrates.

Experimental study on antenna — IC interconnections for electro-textile RFID tags

Wearable passive UHF RFID tags have enormous potential in future body-centric wireless communication and sensing systems, which have countless applications for example in the welfare and health care sectors. Antenna-IC joints in these wireless components are usually the critical parts from the reliability point of view and they operate in an extremely challenging environment. In this study, we demonstrate the wireless performance and reliability of three types of textile RFID tags with the antennas patterned from commercial electro-textile materials and the ICs attached with two different electrically conductive adhesives. Based on our results, the major reliability challenge is to find a suitable conductive adhesive to be used with each different electro-textile material.

Textile-integrated three-dimensional printed and embroidered structures for wearable wireless platforms

In this paper, we present fabrication and performance evaluation of three-dimensional (3D) printed and embroidered textile-integrated passive ultra high frequency radio frequency identification (RFID) platforms. The antennas were manufactured by 3D printing a stretchable silver conductor directly on an elastic band. The electric and mechanical joint between the 3D printed antennas and microchips was formed by gluing with conductive epoxy glue, by printing the antenna directly on top of the microchip structure, and by embroidering with conductive yarn. Initially, all types of fabricated RFID tags achieved read ranges of 8–9 meters. Next, the components were tested for wetting as well as for harsh cyclic strain and bending. The immersing and cyclic bending slightly affected the performance of the tags. However, they did not stop the tags from working in an acceptable way, nor did they have any permanent effect. The epoxy-glued or 3D printed antenna–microchip interconnections were not able to endure harsh stretching. On the other hand, the tags with the embroidered antenna–microchip interconnections showed excellent wireless performance, both during and after a 100 strong stretching cycles. Thus, the novel approach of combining 3D printing and embroidery seems to be a promising way to fabricate textile-integrated wireless platforms.

Inkjet-printed antenna-electronics interconnections in passive UHF RFID tags

We outline the possibilities of inkjet printing in fabrication of passive UHF RFID tag antennas and antenna-electronics interconnections on paper and polyimide substrates. In our method, the silver nanoparticle tag antenna is deposited directly on top of the IC fixture, in order to simplify the manufacturing process by removing one step, i.e., the IC attachment with conductive glue. Our wireless measurement results confirm that the manufactured RFID tags with the printed antenna-lC interconnections achieve peak read ranges of 8.5–10 meters, which makes them comparable to traditional tags with epoxy-glued ICs.

Towards environmentally friendly RFID applications: Fabrication of antennas and interconnections

In this paper, we present environmentally friendly UHF RFID tag antennas that are manufactured by inkjet printing silver nanoparticle ink on a plain paper substrate after finding the most efficient manufacturing parameters and the optimal number of printed layers. The RFID ICs in this work are attached with environmental-friendly and cost-effective conductive adhesive, and the ready RFID tags are evaluated for their wireless performance. According to our measurements, these tags show good performance throughout the global UHF RFID band. The peak read rangeof the fabricated tags can reach about 4 meters, which is suitable for many practical applications.