345 research outputs found
User-interactive wirelessly-communicating “smart” textiles made from multimaterial fibers
En raison de la nature intime des interactions homme-textiles (essentiellement, nous sommes entourés par les textiles 24/7 - soit sous la forme de vêtements que nous portons ou comme rembourrage dans nos voitures, maisons, bureaux, etc.), les textiles intelligents sont devenus des plates-formes de plus en plus attrayantes pour les réseaux de capteurs innovants biomédicaux, transducteurs, et des microprocesseurs dédiés à la surveillance continue de la santé. En même temps, l'approche commune dans le domaine des textiles intelligents consiste en l'adaptation de la microélectronique planaire classique à une sorte de substrat souple. Cela se traduit souvent par de mauvaises propriétés mécaniques et donc des compromis au niveau du confort et de l'acceptation des usagers, qui à leur tour peuvent probablement expliquer pourquoi ces solutions émergent rarement du laboratoire et, à l'exception de certains cas très spécifiques, ne soit pas utilisés dans la vie de tous les jours. Par ailleurs, nous assistons présentement à un changement de paradigme au niveau de l'informatique autonome classique vers le concept de calculs distribués (ou informatique en nuage). Dans ce cas, la puissance de calcul du nœud individuel ou d'un dispositif de textile intelligent est moins importante que la capacité de transmettre des données à l'Internet. Dans ce travail, je propose une nouvelle approche basée sur l'intégration de polymère, verre et métal dans des structures de fibres miniaturisées afin de réaliser des dispositifs de textiles intelligents de prochaine génération avec des fonctionnalités de niveau supérieur (comme la communication sans fil, la reconnaissance tactile, les interconnexions électriques) tout en ayant une forme minimalement envahissante. Tout d'abord, j'étudie différents modèles d'antennes compatibles avec la géométrie des fibres et des techniques de fabrication. Ensuite, je démontre expérimentalement que ces antennes en fibres multi-matériaux peuvent être intégrées dans les textiles lors d’un processus standard de fabrication de textiles. Les tests effectués sur ces textiles ont montré que, pour les scénarios «sur-corps et hors-corps», les propriétés émissives en termes de perte de retour (S11), le patron (diagramme) de radiation, l'efficacité (gain), et le taux d'erreur binaire (TEB) sont directement comparables à des solutions classiques rigides. Ces antennes sont adéquates pour les communications à courte portée des applications de communications sans fil ayant un débit de données de Mo/s (méga-octets par seconde) (via protocoles Bluetooth et IEEE 802.15.4 à la fréquence de 2,4 GHz). Des simulations numériques de taux d'absorption spécifique démontrent également le plein respect des règles de sécurité imposées par Industrie Canada pour les réseaux sans fil à proximité du corps humain. Puisque les matériaux composites de fibres métal-verre-polymère sont fabriqués en utilisant des fibres de silice creuses de diamètre submillimétrique et la technique de dépôt d'argent à l'état liquide, les éléments conducteurs sont protégés de l'environnement et ceci préserve aussi les propriétés mécaniques et esthétiques des vêtements. Cet aspect est confirmé par des essais correspondant aux normes de l'industrie du textile, l'étirement standard et des essais de flexion. De plus, appliquer des revêtements superhydrophobes (WCA = 152º, SA = 6º) permet une communication sans fil sans interruption de ces textiles sous l'application directe de l'eau, même après plusieurs cycles de lavage. Enfin, le prototype de textile intelligent fabriqué interagit avec l'utilisateur à travers un détecteur tactile et transmet les données tactiles à travers le protocole Bluetooth à un smartphone. Cette démonstration valide l’approche des fibres multi-matériaux pour une variété d'applications.As we are surrounded by textiles 24/7, either in the form of garments that we wear or as upholstery in our cars, homes, offices, etc., textiles are especially attractive platforms for arrays of innovative biomedical sensors, transducers, and microprocessors dedicated, among other applications, to continuous health monitoring. In the same time, the common approach in the field of smart textiles consists in adaptation of conventional planar microelectronics to some kind of flexible substrate, which often results in poor mechanical properties and thus compromises wearing comfort and complicates garment care, which results in low user acceptance. This explains why such solutions rarely emerge from the lab and, with the exception of some very specific cases, cannot be seen in the everyday life. Furthermore, we are currently witnessing a global shift from classical standalone computing to the concept of distributed computation (e.g. so-called thin clients and cloud storage). In this context, the computation power of the individual node or smart textile device in this case, becomes progressively less important than the ability to relay data to the Internet. In this work, I propose a novel approach based on the idea of integration of polymer, glass and metal into miniaturized fiber structures in order to achieve next-generation smart textile devices with higher-level functionalities, such as wireless communication, touch recognition, electrical interconnects, with minimally-invasive attributes. First, I investigate different possible fiber-shaped antenna designs and fabrication techniques. Next, I experimentally demonstrate that such multi-material fiber antennas can be integrated into textiles during standard textile manufacturing process. Tests conducted on these textiles have shown that, for on-body and off-body scenarios, the emissive properties in terms of return loss (S11), radiation pattern, efficiency (gain), and bit-error rate (BER) are directly comparable to classic ‘rigid’ solutions and adequately address short-range wireless communications applications at Mbps data-rates (via Bluetooth and IEEE 802.15.4 protocols at 2.4 GHz frequency). Numerical simulations of the specific absorption rate (SAR) also demonstrate full compliance with safety regulations imposed by Industry Canada for wireless body area network devices. Since metal-glass-polymer fiber composites were fabricated using sub-millimetre hollow-core silica fibers and liquid state silver deposition technique, the conductor elements are shielded against the environment and preserve the mechanical and cosmetic properties of the garments. This is confirmed by the textile industry standard stretching and bending tests. Additionally, applied superhydrophobic coatings (WCA=152º, SA=6º) allow uninterrupted wireless communication of the textiles under direct water application even after multiple washing cycles. Finally, I fabricated a user-interactive and wireless-communicating smart textile prototype, that interacts with the user through capacitive touch-sensing and relays the touch data through Bluetooth protocol to a smartphone. This demonstration validates that the proposed approach based on multi-material fibers is suitable for applications to sensor fabrics and bio-sensing textiles connected in real time to mobile communications infrastructures, suitable for a variety of health and life science applications
Fractal Antennas for Wearable Applications
This chapter focuses on the design and fabrication of different types of flexible and inflexible wearable fractal for modern wireless applications with body-area-networks (BANs). A wearable antenna is intended to be a part of clothing used for modern wireless communication purposes. Fractal technology allowed us to design compact antennas and integrate multiple communication services into one device. The proposed antennas were simulated and measured by CST simulator version 2017 and Agilent N9918A VNA respectively. Furthermore, these antennas were fabricated using folded copper. The measured results agree well with the simulated results
Development of Textile Antennas for Energy Harvesting
The current socio-economic developments and lifestyle trends indicate an increasing
consumption of technological products and processes, powered by emergent concepts, such as
Internet of Things (IoT) and smart environments, where everything is connected in a single
network. For this reason, wearable technology has been addressed to make the person, mainly
through his clothes, able to communicate with and be part of this technological network.
Wireless communication systems are made up of several electronic components, which over
the years have been miniaturized and made more flexible, such as batteries, sensors, actuators,
data processing units, interconnectors and antennas. Turning these systems into wearable
systems is a demanding research subject. Specifically, the development of wearable antennas
has been challenging, because they are conventionally built on rigid substrates, hindering their
integration into the garment. That is why, considering the flexibility and the dielectric
properties of textile materials, making antennas in textile materials will allow expanding the
interaction of the user with some electronic devices, by interacting through the clothes. The
electronic devices may thus become less invasive and more discrete.
Textile antennas combine the traditional textile materials with new technologies. They emerge
as a potential interface of the human-technology-environment relationship. They are becoming
an active part in the wireless communication systems, aiming applications such as tracking and
navigation, mobile computing, health monitoring and others. Moreover, wearable antennas
have to be thin, lightweight, of easy maintenance, robust, and of low cost for mass production
and commercialization.
In this way, planar antennas, the microstrip patch type, have been proposed for garment
applications, because this type of antenna presents all these characteristics, and are also
adaptable to any surface. Such antennas are usually formed by assembling conductive (patch
and ground plane) and dielectric (substrate) layers. Furthermore, the microstrip patch
antennas, radiate perpendicularly to a ground plane, which shields the antenna radiation,
ensuring that the human body is exposed only to a very small fraction of the radiation.
To develop this type of antenna, the knowledge of the properties of textile materials is crucial
as well as the knowledge of the manufacturing techniques for connecting the layers with glue,
seam, adhesive sheets and others. Several properties of the materials influence the behaviour
of the antenna. For instance, the bandwidth and the efficiency of a planar antenna are mainly
determined by the permittivity and the thickness of the substrate. The use of textiles in
wearable antennas requires thus the characterization of their properties. Specific electrical
conductive textiles are available on the market and have been successfully used. Ordinary
textile fabrics have been used as substrates. In general, textiles present a very low dielectric constant, εr, that reduces the surface wave
losses and increases the impedance bandwidth of the antenna. However, textile materials are
constantly exchanging water molecules with the surroundings, which affects their
electromagnetic properties. In addition, textile fabrics are porous, anisotropic and
compressible materials whose thickness and density might change with low pressures.
Therefore, it is important to know how these characteristics influence the behaviour of the
antenna in order to minimize unwanted effects.
To explain some influences of the textile material on the performance of the wearable
antennas, this PhD Thesis starts presenting a survey of the key points for the design and
development of textile antennas, from the choice of the textile materials to the framing of the
antenna. An analysis of the textile materials that have been used is also presented. Further,
manufacturing techniques of the textile antennas are described.
The accurate characterization of textile materials to use as a dielectric substrate in wearable
systems is fundamental. However, little information can be found on the electromagnetic
properties of the regular textiles. Woven, knits and nonwovens are inhomogeneous, highly
porous, compressible and easily influenced by the environmental hygrometric conditions,
making their electromagnetic characterization difficult. Despite there are no standard
methods, several authors have been adapting techniques for the dielectric characterization of
textiles. This PhD Thesis focuses on the dielectric characterization of the textile materials,
surveying the resonant and non-resonant methods that have been proposed to characterize the
textile and leather materials. Also, this PhD Thesis summarizes the characterization of textile
materials made through these methods, which were validated by testing antennas that
performed well.
Further a Resonant-Based Experimental Technique is presented. This new method is based on
the theory of resonance-perturbation, extracting the permittivity and loss tangent values based
on the shifts caused by the introduction of a superstrate on the patch of a microstrip antenna.
The results obtained using this method have shown that when positioning the roughest face of
the material under test (MUT) in contact with the resonator board, the extracted dielectric
constant value is lower than the one extracted with this face positioned upside-down. Based
on this observation, superficial properties of textiles were investigated and their influence on
the performance of antennas was analysed.
Thus, this PhD Thesis relates the results of the dielectric characterization to some structural
parameters of textiles, such as surface roughness, superficial and bulk porosities. The results
show that both roughness and superficial porosity of the samples influence the measurements,
through the positioning of the probes. Further, the influence of the positioning of the dielectric
material on the performance of textile microstrip antennas was analysed. For this, twelve
prototypes of microstrip patch antennas were developed and tested. The results show that,
despite the differences obtained on the characterization when placing the face or reverse-sides of the MUT in contact with the resonator board, the obtained average result of εr is well suited
to design antennas ensuring a good performance.
According to the European Commission Report in 2009, “Internet of Things — An action plan for
Europe”, in the next years, the IoT will be able to improve the quality of life, especially in the
health monitoring field. In the Wireless Body Sensor Network (WBSN) context, the integration
of textile antennas for energy harvesting into smart clothing is a particularly interesting
solution for a continuous wirelessly feed of the devices. Indeed, in the context of wearable
devices the replacement of batteries is not easy to practice. A specific goal of this PhD Thesis
is thus to describe the concept of the energy harvesting and then presents a survey of textile
antennas for RF energy harvesting. Further, a dual-band printed monopole textile antenna for
electromagnetic energy harvesting, operating at GSM 900 and DCS 1800 bands, is also proposed.
The antenna aims to harvest energy to feed sensor nodes of a wearable health monitoring
system. The gains of the antenna are around 1.8 dBi and 2.06 dBi allied with a radiation
efficiency of 82% and 77.6% for the lowest and highest frequency bands, respectively.
To understand and improve the performance of the proposed printed monopole textile antenna,
several manufacturing techniques are tested through preliminary tests, to identify promising
techniques and to discard inefficient ones, such as the gluing technique. Then, the influence
of several parameters of the manufacturing techniques on the performance of the antenna are
analysed, such as the use of steam during lamination, the type of adhesive sheet, the
orientation of the conductive elements and others. For this, seven prototypes of the printed
monopole textile antenna were manufactured by laminating and embroidering techniques.
The measurement of the electrical surface resistance, Rs, has shown that the presence of the
adhesive sheet used on the laminating process may reduce the conductivity of the conductive
materials. Despite that, when measuring the return loss of printed monopole antennas
produced by lamination, the results show the antennas have a good performance. The results
also show that the orientation of the conductive fabric does not influence the performance of
the antennas. However, when testing embroidered antennas, the results show that the
direction and number of the stitches in the embroidery may influence the performance of the
antenna and should thus be considered during manufacturing.
The textile antennas perform well and their results support and give rise to the new concept
of a continuous substrate to improve the integration of textile antennas into clothing, in a more
comfortable and pleasure way. A demonstrating prototype, the E-Caption: Smart and
Sustainable Coat, is thus presented. In this prototype of smart coat, the printed antenna is fully
integrated, as its dielectric is the textile material composing the coat itself. The E-Caption
illustrates the innovative concept of textile antennas that can be manipulated as simple
emblems. The results obtained testing the antenna before and after its integration into cloth,
show that the integration does not affect the behaviour of the antenna. Even on the presence
of the human body the antenna is able to cover the proposed resonance frequencies (GSM 900
and DCS 1800 bands) with the radiation pattern still being omnidirectional. At last, the exponential growth in the wearable market boost the industrialization process of
manufacturing textile antennas. As this research shows, the patch of the antennas can be easily
and efficiently cut, embroidered or screen printed by industrial machines. However, the
conception of a good industrial substrate that meets all the mechanical and electromagnetic
requirements of textile antennas is still a challenge. Following the continuous substrate
concept presented and demonstrated through the E-Caption, a new concept is proposed: the
continuous Substrate Integrating the Ground Plane (SIGP). The SIGP is a novel textile material
that integrates the dielectric substrate and the conductive ground plane in a single material,
eliminating one laminating process. Three SIGP, that are weft knitted spacer fabrics having one
conductive face, were developed in partnership with the Borgstena Textile Portugal Lda,
creating synergy between research in the academy and industry. The results of testing the
performance of the SIGP materials show that the integration of the ground plane on the
substrate changes the dielectric constant of the material, as a consequence of varying the
thickness. Despite this, after the accurate dielectric and electrical characterization, the SIGP
I material has shown a good performance as dielectric substrate of a microstrip patch antenna
for RF energy harvesting. This result is very promising for boosting the industrial fabrication of
microstrip patch textile antennas and their mass production and dissemination into the IoT
network, guiding future developments of smart clothing and wearables.Os atuais desenvolvimentos socioeconómicos e tendências de estilo de vida apontam para um
crescimento do consumo de produtos e processos tecnológicos, impulsionado por conceitos
emergentes como a Internet das Coisas, onde tudo tudo está conectado em uma única rede.
Por esta razão, as tecnologias usáveis (wearable) estão a afirmar-se propondo soluções que
tornam o utilizador possivelmente através das suas roupas, capaz de comunicar com e fazer
parte desta rede.
Os sistemas de comunicações sem fios são constituídos por diversos componentes eletrónicos,
que com o passar dos anos foram sendo miniaturizados e fabricados em materiais flexíveis, tais
como as baterias, os sensores, as unidades de processamento de dados, as interconexões e as
antenas. Tornar os sistemas de comunicações sem fios em sistemas usáveis requer trabalho de
investigação exigente. Nomeadamente, o desenvolvimento de antenas usáveis tem sido um
desafio, devido às antenas serem tradicionalmente desenvolvidas em substratos rígidos, que
dificultam a sua integração no vestuário. Dessa forma, considerando a flexibilidade e as
propriedades dielétricas dos materiais têxteis, as antenas têxteis trazem a promessa de
permitir a interacção dos utilizadores com os dispositivos eletrónicos através da roupa,
tornando os dispositivos menos invasivos e mais discretos.
As antenas têxteis combinam os materiais têxteis tradicionais com novas tecnologias e emergem
assim como uma potencial interface de fronteira entre seres humanos-tecnologias-ambientes.
Expandindo assim a interação entre o utilizador e os dispositivos eletrónicos ao recurso do
vestuário. Assim, através das antenas têxteis, o vestuário torna-se uma parte ativa nos sistemas
de comunicação sem fios, visando aplicações como rastreamento e navegação, computação
móvel, monitorização de saúde, entre outros. Para isto, as antenas para vestir devem ser finas,
leves, de fácil manutenção, robustas e de baixo custo para produção em massa e
comercialização.
Desta forma, as antenas planares do tipo patch microstrip têm sido propostas para aplicações
em vestuário, pois apresentam todas estas características e também são adaptáveis a qualquer
superfície. Estas antenas são geralmente formadas pela sobreposição de camadas condutoras
(elemento radiante e plano de massa) e dielétricas (substrato). Além disso, as antenas patch
microstrip irradiam perpendicularmente ao plano de massa, que bloqueia a radiação da antena,
garantindo que o corpo humano é exposto apenas a uma fração muito pequena da radiação.
Para desenvolver este tipo de antena, é crucial conhecer as propriedades dos materiais têxteis,
bem como as técnicas de fabricação para conectar as camadas, com cola, costuras, folhas
adesivas, entre outros. Diversas propriedades dos materiais influenciam o comportamento da
antena. Por exemplo, a permitividade e a espessura do substrato determinam a largura de banda e a eficiência de uma antena planar. O uso de têxteis em antenas usáveis requer assim
uma caracterização precisa das suas propriedades. Os têxteis condutores elétricos são materiais
específicos que estão disponíveis comercialmente em diversas formas e têm sido utilizados com
sucesso para fabricar o elemento radiante e o plano de massa das antenas. Para fabricar o
substrato dielétrico têm sido utilizados materiais têxteis convencionais.
Geralmente, os materiais têxteis apresentam uma constante dielétrica (εr) muito baixa, o que
reduz as perdas de ondas superficiais e aumenta a largura de banda da antena. No entanto, os
materiais têxteis estão constantemente a trocar moléculas de água com o ambiente em que
estão inseridos, o que afeta as suas propriedades eletromagnéticas. Além disso, os tecidos e os
outros materiais têxteis planares são materiais porosos, anisotrópicos e compressíveis, cuja
espessura e densidade variam sob muito baixas pressões. Portanto, é importante saber como
estas grandezas e características estruturais influenciam o comportamento da antena, de forma
a minimizar os efeitos indesejáveis.
Para explicar algumas das influências do material têxtil no desempenho das antenas usáveis,
esta Tese de Doutoramento começa por fazer o estado da arte sobre os pontos-chave para o
desenvolvimento de antenas têxteis, desde a escolha dos materiais têxteis até ao processo de
fabrico da antena. Além disso, a tese identifica e apresenta uma análise dos materiais têxteis
e técnicas de fabricação que têm sido utilizados e referidos na literatura.
A caracterização rigorosa dos materiais têxteis para usar como substrato dielétrico em sistemas
usáveis é fundamental. No entanto, pouca informação existe sobre a caracterização das
propriedades eletromagnéticas dos têxteis vulgares. Como já referido, os tecidos, malhas e
não-tecidos são materiais heterogéneos, altamente porosos, compressíveis e facilmente
influenciados pelas condições higrométricas ambientais, dificultando a sua caracterização
eletromagnética. Não havendo nenhum método padrão, vários autores têm vindo a adaptar
algumas técnicas para a caracterização dielétrica dos materiais têxteis. Esta Tese de
Doutoramento foca a caracterização dielétrica dos materiais têxteis, revendo os métodos
ressonantes e não ressonantes que foram propostos para caracterizar os materiais têxteis e o
couro. Além disso, esta Tese de Doutoramento resume a caracterização de dieléctricos têxteis
feita através dos métodos revistos e que foi validada testando antenas que apresentaram um
bom desempenho.
No seguimento da revisão, apresenta-se uma Técnica Experimental Baseada em Ressonância.
Esta nova técnica baseia-se na teoria da perturbação de ressonância, sendo a permitividade e
tangente de perda extraídas com base nas mudanças de frequência causadas pela introdução
de um superstrato no elemento radiante de uma antena patch microstrip. Os resultados de
caracterização obtidos através deste método revelam que, ao posicionar a face mais rugosa do
material em teste em contato com a placa de ressonância, o valor da constante dielétrica
extraída é inferior ao valor extraído quando esta face é colocada ao contrário. Com base nesta
observação, as propriedades estruturais da superfície dos materiais têxteis foram investigadas
e a sua influência no desempenho das antenas foi analisada. Assim, esta Tese de Doutoramento relaciona os resultados da caracterização dielétrica com
alguns parâmetros estruturais dos materiais, como rugosidade da superfície, porosidades
superficial e total. Os resultados mostram que tanto a rugosidade como a porosidade superficial
das amostras influenciam os resultados, que dependem assim do posicionamento do material
que está a ser testado. Também foi analisada a influência do posicionamento do material
dielétrico na performance das antenas têxteis tipo patch microstrip. Para isso, foram
desenvolvidos e testados doze protótipos de antenas patch microstrip. Os resultados mostram
que, apesar das diferenças observadas durante o processo de caracterização, o valor médio da
permitividade é adequado para a modelação das antenas, garantindo um bom desempenho.
De acordo com o relatório da Comissão Europeia, “Internet das Coisas - Um plano de ação para
a Europa”, emitido em 2009, nos próximos anos a Internet das Coisas poderá melhorar a
qualidade de vida das pessoas, nomeadamente pela monitorização da saúde. No contexto das
Redes de Sensores Sem Fios do Corpo Humano, a integração de antenas têxteis para recolha de
energia em roupas inteligentes é uma solução particularmente interessante, pois permite uma
alimentação sem fios e contínua dos dispositivos. De fato, nos dispositivos usáveis a substituição
de baterias não é fácil de praticar. Um dos objetivos específicos desta Tese de Doutoramento
é, portanto, descrever o conceito de recolha de energia e apresentar o estado da arte sobre
antenas têxteis para recolha de energia proveniente da Rádio Frequência (RF). Nesta tese, é
também proposta uma antena impressa do tipo monopolo de dupla banda, fabricada em
substrato têxtil, para recolha de energia eletromagnética, operando nas bandas GSM 900 e DCS
1800. A antena visa recolher energia para alimentar os nós de sensores de um sistema usável
para monitorização da saúde. Os ganhos da antena apresentada foram cerca de 1.8 dBi e 2.06
dBi, aliados a uma eficiência de radiação de 82% e 77.6% para as faixas de frequência mais
baixa e alta, respetivamente.
Para entender e melhorar o desempenho da antena impressa tipo monopolo de dupla banda em
substrato têxtil, várias técnicas de fabrico foram testadas através de testes preliminares, de
forma a identificar as técnicas promissoras e a descartar as ineficientes, como é o caso da
técnica de colagem. De seguida, analisou-se a influência de vários parâmetros das técnicas de
fabrico sobre o desempenho da antena, como o uso de vapor durante a laminação, o tipo de
folha adesiva, a orientação dos elementos irradiantes e outros. Para isto, sete protótipos da
antena têxtil monopolar impressa foram fabricados por técnicas de laminação e bordado.
As medições da resistência elétrica superficial, Rs, mostrou que a presença da folha adesiva
usada no processo de laminagem pode reduzir a condutividade dos materiais condutores. Apesar
disso, ao medir o S11 das antenas impressas tipo monopolo produzidas por laminagem, os
resultados mostram que as antenas têm uma boa adaptação da impedância. Os resultados
também mostram que a orientação do tecido condutor, neste caso um tafetá, não influencia o
desempenho das antenas. No entanto, ao testar antenas bordadas, os resultados mostram que
a direção e o número de pontos no bordado podem influenciar o desempenho da antena e,
portanto, estas são características que devem ser consideradas durante a fabricação. De um modo geral, as antenas têxteis funcionam bem e seus resultados suportam e dão origem
ao um novo conceito de substrato contínuo para melhorar a integração de antenas têxteis no
vestuário, de maneira mais confortável e elegante. A tese apresenta um protótipo
demonstrador deste conceito, o E-Caption: A Smart and Sustainable Coat. Neste protótipo de
casaco inteligente, a antena impressa está totalmente integrada, pois o seu substrato dielétrico
é o próprio mat
Artificial Magnetic Conductor Integrated Textile Monopole Antenna
Wearable antenna is a fast growing field in application-oriented research, which introduced a new generation of garments capable of monitoring wear health, as well as environmental states. This thesis is concerned with the design and fabrication of a compact textile wearable antenna at operating frequency within the Industrial, Scientific and Medical (ISM) band, intended for integration into a flight jacket of the astronaut inside the habitat. The antenna is integrated with artificial material known as High Impedance Surface (HIS) for performance enhancement. The purpose of the system is to constantly monitor vital signals of the astronauts.
The entire design cycle of wearable Co-Planar Waveguide (CPW) fed monopole antenna, starting from simulation-based design to fabricated prototype and antenna testing under different conditions was carried out in this thesis. Because of the lossy nature of human body tissues, the radiation efficiency of the antenna will be reduced due to the absorption of the radiated energy. Hence, changes in the radiation characteristics of the wearable antenna like operating frequency, gain and impedance bandwidth will take place. To overcome these challenges, HIS has been suggested and integrated with the monopole antenna to isolate the antenna from the ambient environments. This wearable antenna was tested under real operating conditions such as bending and crumpling conditions.
Moreover, as the antenna operates near human body tissues, Specific Absorption Rate (SAR) assessment is required to consider the safety concerns of the antenna system. SAR analysis based on simulation results has been carried out in this thesis to show a significant reduction in SAR with the usage of HIS in the antenna system
Study of Wearable Antenna for Body Area Network
Wearable frameworks are calling a great deal of considerations lately. Savvy watches, virtual reality glasses, sports arm ornaments together with different smart wearable checking gadgets have been tossed into business sectors. Web of things is growing rapidly. To associate everything and everyone is in this way offered a plausibility and is a pattern that is on the roadway to its acknowledgment. The key innovation of this region has turned into a hot examination theme. Use of wearable materials in the radio reception apparatus segment has been seen on the rising as a result of the present downsizing of remote contraptions. A wearable radio receiving wire is planned to be a bit of the clothing used for correspondence purposes, which consolidates following and course, flexible figuring. In this paper different wearable antennas analyze
Synchronous wearable wireless body sensor network composed of autonomous textile nodes
A novel, fully-autonomous, wearable, wireless sensor network is presented, where each flexible textile node performs cooperative synchronous acquisition and distributed event detection. Computationally efficient situational-awareness algorithms are implemented on the low-power microcontroller present on each flexible node. The detected events are wirelessly transmitted to a base station, directly, as well as forwarded by other on-body nodes. For each node, a dual-polarized textile patch antenna serves as a platform for the flexible electronic circuitry. Therefore, the system is particularly suitable for comfortable and unobtrusive integration into garments. In the meantime, polarization diversity can be exploited to improve the reliability and energy-efficiency of the wireless transmission. Extensive experiments in realistic conditions have demonstrated that this new autonomous, body-centric, textile-antenna, wireless sensor network is able to correctly detect different operating conditions of a firefighter during an intervention. By relying on four network nodes integrated into the protective garment, this functionality is implemented locally, on the body, and in real time. In addition, the received sensor data are reliably transferred to a central access point at the command post, for more detailed and more comprehensive real-time visualization. This information provides coordinators and commanders with situational awareness of the entire rescue operation. A statistical analysis of measured on-body node-to-node, as well as off-body person-to-person channels is included, confirming the reliability of the communication system
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