High-Strength, Metalized Fibers for Conformal Load Bearing Antenna Applications

Shin

et al. 2015

Adv Funct Materials

525

417

Stretchable conductive fibers have received significant attention due to their possibility of being utilized in wearable and foldable electronics. Here, highly stretchable conductive fiber composed of silver nanowires (AgNWs) and silver nanoparticles (AgNPs) embedded in a styrene–butadiene–styrene (SBS) elastomeric matrix is fabricated. An AgNW‐embedded SBS fiber is fabricated by a simple wet spinning method. Then, the AgNPs are formed on both the surface and inner region of the AgNW‐embedded fiber via repeated cycles of silver precursor absorption and reduction processes. The AgNW‐embedded conductive fiber exhibits superior initial electrical conductivity (σ0 = 2450 S cm−1) and elongation at break (900% strain) due to the high weight percentage of the conductive fillers and the use of a highly stretchable SBS elastomer matrix. During the stretching, the embedded AgNWs act as conducting bridges between AgNPs, resulting in the preservation of electrical conductivity under high strain (the rate of conductivity degradation, σ/σ0 = 4.4% at 100% strain). The AgNW‐embedded conductive fibers show the strain‐sensing behavior with a broad range of applied tensile strain. The AgNW reinforced highly stretchable conductive fibers can be embedded into a smart glove for detecting sign language by integrating five composite fibers in the glove, which can successfully perceive human motions.

Section: Resultsmentioning

confidence: 99%

Ag Nanowire Reinforced Highly Stretchable Conductive Fibers for Wearable Electronics

Shin

et al. 2015

Adv Funct Materials

525

417

IEEE Antennas Propag. Mag.

“…The simplest approach is to integrate, knit or embroider conducting wires, copper tape or conductive yarns into a piece of clothing [41]- [43], [45]. In 2004, Salonen et al [33] assembled a dual-band antenna by mounting a Uslot patch, created in copper tape, on a fleece fabric substrate.…”

Section: B Materials and Technologiesmentioning

confidence: 99%

Wearable Antennas for Off-Body Radio Links at VHF and UHF Bands: Challenges, the state of the art, and future trends below 1 GHz

Nepa

Rogier

2015

106

Abstract-An in-depth survey of wearable antennas for offbody radio links in the VHF and UHF frequency bands (below 1 GHz) is presented. The review encompasses distinctive specifications, design criteria and challenges, material characterization procedures, antenna topologies and technologies, multi-antenna systems, dedicated testing procedures, applications and future trends.Index Terms-Wearable antennas, body-worn antennas, textile antennas, embroidered antennas, VHF antennas, UHF antennas, antennas for body-centric communications, antennas for body area networks, antennas for personal area networks, antennas for off-body wireless communications. I. INTRODUCTIONhere are several existing and forthcoming wireless applications that either require or can benefit from one or more antennas that are directly stitched on a piece of clothing or a garment, or integrated into a personal accessory (such as shoes, glasses, buttons, helmets). These antennas are usually referred to as body-worn antennas, textile antennas, BAN (Body Area Network) antennas, antennas for body-centric communications, wearable antennas. The last term is the one that is going to be used in this paper, as it denotes any antenna that is small and light enough to be worn or carried on one's body.In the last decades, hundreds of scientific papers on wearable antennas have been published in the open literature [1]- [8]. Therefore, for the sake of completeness and clarity, a valuable analysis of the state-of-the-art on wearable antennas should be limited to antennas for a specific application, a given frequency range, or a chosen antenna technology. In this context, the present review focuses on wearable antennas operating in the VHF band and part of the UHF frequency band (below 1 GHz). Choosing 1 GHz as an upper boundary for this review is highly relevant, as the operating frequency is usually the main parameter to discriminate among available antenna topologies, technologies and characterization techniques. Moreover, we limit our discussion on antennas for off-body radio links, also excluding antennas integrated into mobile terminals/cases and operating close to the body. Specifically, only wearable antennas that can be used separately from the radio unit are of interest here.VHF/UHF wearable antennas are mostly used in professional mobile radio communications for soldiers, emergency operators and law-enforcement personnel. VHF As far as VHF/UHF wearable antennas are concerned, many of their distinctive features are related to the fact that the corresponding free-space wavelength (with 30cm<<10m when 30MHz

International Journal of Antennas and Propagation

“…Several embroidered antennas and wearable sensors have already been reported in the literature using conductive fibers on textiles and polymer composite substrates [2,[6][7][8][9][10][11][12]. Embroidered wearable RFID tags on textile and polymer composites have also been reported [13,14].…”

Section: Introductionmentioning

confidence: 99%

Design and Characterization of a Flexible Wideband Antenna Using Polydimethylsiloxane Composite Substrate

Abbas

Desai

Volakis

et al. 2018

The design and characterization of a simple, flexible wideband antenna using polydimethylsiloxane (PDMS) composite are presented. Conductive fibers are used to construct the metallic parts on a PDMS composite. To characterize the performance, two identical antennas are designed, one using the PDMS composite while the other on conventional dielectric materials. It was observed that both antennas behave well in terms of the matched bandwidth; however, the radiation towards the broadside direction is reduced when using the PDMS composite as substrate, particularly at higher frequencies. The antenna exhibits a matched bandwidth of 59.9%, ranging from 3.43 to 11.1 GHz. Moreover, the bending analysis carried out for different scenarios show that the wideband behavior of the antenna is well preserved and the variation reaches a maximum of 1% variation.