Crumpled textile antennas

The performance of a dual-band textile antenna under two-dimensional crumpling conditions is described. Both input impedance and radiation patterns are investigated based on numerical and experimental methods at 2.45 and 5.8 GHz. The return loss for the coplanar antenna is affected by the most severe crumpling at the higher frequency band, while the radiation patterns remain acceptable at both bands

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

On the Development of Conductive Textile Antennas

UWB systems are becoming increasingly utilized due to their use in a variety of applications. Meanwhile, many advances have been achieved in the realm of conductive textiles. These textiles can be used as a sensing system or implemented wearable antennas. Combining these two applications is attractive for a number of reasons. First, wearable antennas constructed entirely from fabric offer a cost- effective, flexible solution when compared to rigid antennas. Second UWB technology is also attractive for body area network applications due to the low power operation and the inherent low radiated power in its system design. In our implementation accurately defined textile antennas have been developed using a laser machine with high precision cutting capabilities. The textile antennas are comprised of a conductive fabric layer that is laser defined and can be easily incorporated into uniforms and garments using a simple iron-on process. We have developed and present a monopole antenna design geared towards UWB applications. We show that these UWB textile antennas can be applied to localization systems and can provide accurate estimation of wearers location. Wide-band textile slot antennas have been developed too. The antennas are composed of three textile layers: the top and bottom are conducting layers and are precisely defined by a laser cutting machine, while the third layer is a textile dielectric layer sandwiched between these two conducting layers. A single, two-element and four-element array slot antennas have been developed and successfully tested. The developed antennas offer flexible, light-weight and bendable properties. The iron-on process allows for the fabric to be washed without losing its adhesion. The antenna fabrication and the capabilities of the laser precision technique and its extension to development of large area antenna arrays will be presented. Conductive textiles can also be implemented to meet the requirements of combat wound detection systems. Using these textiles, a fabric-based sensor can be developed to accurately detect and localize the bullets penetration

An efficient technique based on polynomial chaos to model the uncertainty in the resonance frequency of textile antennas due to bending

The generalized polynomial chaos theory is combined with a dedicated cavity model for curved textile antennas to statistically quantify variations in the antenna's resonance frequency under randomly varying bending conditions. The nonintrusive stochastic method solves the dispersion relation for the resonance frequencies of a set of radius of curvature realizations corresponding to the Gauss quadrature points belonging to the orthogonal polynomials having the probability density function of the random variable as a weighting function. The formalism is applied to different distributions for the radius of curvature, either using a priori known or on-the-fly constructed sets of orthogonal polynomials. Numerical and experimental validation shows that the new approach is at least as accurate as Monte Carlo simulations while being at least 100 times faster. This makes the method especially suited as a design tool to account for performance variability when textile antennas are deployed on persons with varying body morphology

Foldable all-textile cavity-backed slot antennas for personal UWB localization

An all-textile multimoded cavity-backed slot antenna has been designed and fabricated for body-worn impulse radio ultra-wideband (IR-UWB) operation in the 3,744-4,742.4 MHz frequency band, thereby covering Channels 2 and 3 of the IEEE 802.15.4a standard. Its light weight, mechanical flexibility, and small footprint of 35 mm x 56 mm facilitate integration into textile for radio communication equipment for first aid responders, personal locator beacons, and equipment for localization and medical monitoring of children or the elderly. The antenna features a stable radiation pattern and reflection coefficient in diverse operating conditions such as in free space, when subject to diverse bending radii and when deployed on the torso or upper right arm of a test person. The high isolation toward the wearer's body originates from the antenna's hemispherical radiation pattern with a -3 dB beamwidth of 120 degrees and a front-to-back ratio higher than 11 dB over the entire band. Moreover, the antenna exhibits a measured maximum gain higher than 6.3 dBi and a radiation efficiency over 75%. In addition, orientation-specific pulse distortion introduced by the antenna element is analyzed by means of the System Fidelity Factor (SFF). The SFF of the communication link between two instances of this antenna is higher than 94% for all directions within the antenna's -3 dB beamwidth. This easily wearable and deployable antenna is suitable to support IR-UWB localization with an accuracy in the order of 5 cm

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, localization and wireless communication systems, in the meanwhile being comfortable and invisible to the wearer. New design strategies combined with dedicated signal processing techniques greatly enhance the robustness of these systems. On the one hand, the large amount of real estate available in public regulated services' 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 recent textile antenna prototypes integrated in professional garments, providing sensing, positioning and communication capabilities

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

Design and performance analysis of a purely textile spiral antenna for on-body NFC applications

Novel combinations of materials and construction techniques are key for the development of new textile antenna configurations for on-body applications. Stretchable, flexible and conformable features of textile antennas are one of the hot research topics nowadays. This work gives a step forward with new designs of purely textile spiral antennas with flexible and robust features for Near Field Communications (NFC) on-body applications. Their performance is successfully validated with a real NFC chipset, and some design and construction considerations are offered for novel textile materials