A historical review of the development of electronic textiles

Textiles have been at the heart of human technological progress for thousands of years, with textile developments closely tied to key inventions that have shaped societies. The relatively recent invention of electronic textiles is set to push boundaries again and has already opened up the potential for garments relevant to defense, sports, medicine, and health monitoring. The aim of this review is to provide an overview of the key innovative pathways in the development of electronic textiles to date using sources available in the public domain regarding electronic textiles (E-textiles); this includes academic literature, commercialized products, and published patents. The literature shows that electronics can be integrated into textiles, where integration is achieved by either attaching the electronics onto the surface of a textile, electronics are added at the textile manufacturing stage, or electronics are incorporated at the yarn stage. Methods of integration can have an influence on the textiles properties such as the drapability of the textile

The next generation textile antennas based on substrate integrated waveguide technology

Textile antennas for body-worn applications have some very specific requirements and needs. From an electrical engineer's point of view, good radiation characteristics and impedance matching to the active electronics are important. From the wearer's perspective, the antenna should be unobtrusively integrated into the clothing, and the smart textile comfortable to wear. New techniques offer the potential to fulfill these different needs. One new approach consists of applying metalized eyelets to implement substrate integrated waveguide technology on textile materials. This results in high-performance on-body antennas with excellent behavior in close proximity of the human body. Two realizations are discussed: a wideband design and a miniaturized half mode substrate integrated waveguide dual-band design. Both yield excellent free-space and on-body performance, and superb antenna-body isolation, automatically resulting in very robust characteristics when deployed on-body

A through wall doppler radar system: active textile antenna design, prototyping and experiment

Using garments as a platform for electronic sensing and communication systems opens up a wide range of novel and exciting applications. By carefully tailoring the antenna properties and by adopting a dedicated design strategy, a robust wearable antenna system can be obtained onto which all necessary electronics are integrated. In this contribution, the dedicated design for approach of a low-weight, wearable Doppler radar system fabricated on textile materials is presented. The system, fully integrated into a rescue worker's garment, is capable of detecting moving objects behind a barrier. It relies on an array of four textile transmit antennas to scan the surroundings. At the receiving end, an active wearable receive antenna is deployed to capture the reflected signals. It is demonstrated that the on-body system is capable of detecting moving subjects in indoor environments, including through-wall scenarios

Surface morphology of polyimide thin film dip-coated on polyester filament for dielectric layer in fibrous organic field effect transistor

The idea of wearable electronics automatically leads to the concept of integrating electronic functions on textile substrates. Since this substrate type implies certain challenges in comparison with their rigid electronic companions, it is of utmost importance to investigate the application of materials for generating the electronic functions on the textile substrate. Only when interaction of materials and textile substrate is fully understood, the electronic function can be generated on the textile without changing the textile's properties, being flexible or stretchable. This research deals with the optimization of the dielectric layer in a fibrous organic field effect transistor (OFET). A transistor can act as an electrical switch in a circuit. In this work, the polyimide layer was dip-coated on a copper-coated polyester filament. After thoroughly investigating the process conditions, best results with minimal thickness and roughness at full insulation could be achieved at a dip-coating speed of 50 mm/min. The polyimide solution was optimal at 15w% and the choice for the solvent NMP was made. In this paper, details on the pre-treatment methods, choice of solvent and dip-coating speed and their effect on layer morphology and thickness, electrical properties and roughness are reported. Results show that the use of polyimide as a dielectric layer in the architecture of a fibrous OFET is promising. Further research deals with the application of the semiconductor layer within the mentioned architecture, to finally build an OFET on a filament for application in smart textiles

Active textile antennas in professional garments for sensing, localisation and communication

New wireless wearable monitoring systems integrated in professional garments require a high degree of reliability and autonomy. Active textile antenna systems may serve as platforms for body-centric sensing, localisation, and wireless communication systems, in the meanwhile being comfortable and invisible to the wearer. We present a new dedicated comprehensive design paradigm and combine this with adapted signal-processing techniques that greatly enhance the robustness and the autonomy of these systems. On the one hand, the large amount of real estate available in professional rescue worker garments may be exploited to deploy multiple textile antennas. On the other hand, the size of each radiator may be designed large enough to ensure high radiation efficiency when deployed on the body. This antenna area is then reused by placing active electronics directly underneath and energy harvesters directly on top of the antenna patch. We illustrate this design paradigm by means of recent textile antenna prototypes integrated in professional garments, providing sensing, positioning, and communication capabilities. In particular, a novel wearable active Galileo E1-band antenna is presented and fully characterized, including noise figure, and linearity performance

Digital lace:a collision of responsive technologies

Designing with properties such as colour-change and light using electronics and digital control brings new challenges within art and design, and a range of new possibilities for aesthetics, tactility and functionality. Heimtextil 2014 (accessed April 2014) promotes emerging materials and technologies as one of four trends which highlight the increasing demand for unique products utilizing novel material properties and digital making. However, there is still limited insight into the creative potential of these materials that are fundamental to the exploitation of 'smart' material properties, the development of new 'smart' surfaces and digital tools that facilitate designing with colour-change and light-emitting properties specific to textiles. This submission to the Fiber arts category presents new material concepts as Digital Lace: a novel, multifaceted textile which will be presented as an interactive table runner for a digitally manufactured console table. Digital Lace explicitly pools together the digital-craft skills base and disparate expertise of printed textile practitioner and thermochromic specialist, Sara Robertson (SR) and constructed textile practitioner and light-emitting optical fibre specialist, Sarah Taylor (ST). Within the context of 'smart', material development and experimentation, Digital lace exploits and amalgamates the responsive technologies of dye and fibre with digital-control

An automated process for inclusion of package dies and circuitry within a textile yarn

The integration of small electronic components into textile fabrics, without compromising the textile qualities such as flexibility and conformability, is necessary in ensuring wider adoption of electronic textiles. A solution is to use flexible, electronic yarns that incorporate electronic components within the fibers of the yarn. The production of these novel yarns was initially a craft skill, with inclusion of electronics within each section of yarn taking 60–90 minutes. A prototype, automated production process was developed to speed up the manufacturing process to 6 minutes. This paper describes the process, using machinery and methods from both electronics and textiles applications

Wearable flexible lightweight modular RFID tag with integrated energy harvester

A novel wearable radio frequency identification (RFID) tag with sensing, processing, and decision-taking capability is presented for operation in the 2.45-GHz RFID superhigh frequency (SHF) band. The tag is powered by an integrated light harvester, with a flexible battery serving as an energy buffer. The proposed active tag features excellent wearability, very high read range, enhanced functionality, flexible interfacing with diverse low-power sensors, and extended system autonomy through an innovative holistic microwave system design paradigm that takes antenna design into consideration from the very early stages. Specifically, a dedicated textile shorted circular patch antenna with monopolar radiation pattern is designed and optimized for highly efficient and stable operation within the frequency band of operation. In this process, the textile antenna's functionality is augmented by reusing its surface as an integration platform for light-energy-harvesting, sensing, processing, and transceiver hardware, without sacrificing antenna performance or the wearer's comfort. The RFID tag is validated by measuring its stand-alone and on-body characteristics in free-space conditions. Moreover, measurements in a real-world scenario demonstrate an indoor read range up to 23 m in nonline-of-sight indoor propagation conditions, enabling interrogation by a reader situated in another room. In addition, the RFID platform only consumes 168.3 mu W, when sensing and processing are performed every 60 s

Novel wearable antenna systems for high datarate mobile communication in healthcare

In critical healthcare applications, there is a need for reliable wideband mobile communication links, implemented by portable units with sufficient autonomy. We present the latest generation wearable antenna systems for invisible and comfortable integration in patients' or caregivers' garments. These active textile modules boast excellent performance and reliability, thanks to innovative antenna topologies, leveraged by the application of substrate integrated waveguide technology, pervasive integration of electronics and energy harvesters, and the application of multi-antenna processing techniques. Applications range from mobile communication links between caregivers and a coordination centre during interventions, over wireless sensor systems for patient monitoring, to relaying videos streams between a wireless endoscopy capsule and a remote control station