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Aquest projecte pretén contribuir al camp dels sensors wearables, especialment en el context de la salut i la monitorització del moviment. La combinació de tecnologia resistiva tridimensional i integració en tèxtil obre noves possibilitats per a la monitorització fiable i còmoda de l'angle de flexió del genoll en temps real, amb possibles aplicacions en àmbits com la rehabilitació física i la mobilitat de persones discapacitades. El projecte s’ha dut a terme des de l’elecció del model, els materials, el bordat del sensor al tèxtil, programació amb Arduino per la realització de les mesures, adquisició de dades i interfície gràfica per a la observació dels resultats. Aquests requeriments formen la base essencial del desenvolupament del sensor resistiu tridimensional integrat en tèxtil, assegurant la seva eficàcia en la captació i mesura dels moviments articulatoris amb aplicacions rellevants en àrees de salut, rehabilitació i rendiment físic. Els resultats obtinguts revelen que els sensors bordats amb fil conductor sobre un teixit elàstic permeten la construcció d'un sistema eficaç per mesurar i monitoritzar l'angle de flexió del genoll. El projecte pot assolir un futur destacat en el món dels teixits intel·ligents. Pel que fa al disseny del sensor, s'ha constatat la diversitat de combinacions de materials i dissenys disponibles, indicant la necessitat d'una investigació més detallada. No obstant això, ofereix l'avantatge de possibilitar dissenys personalitzats segons el producte i l'ús específic. Tot i que el projecte s'ha centrat en la incorporació d'aquests sensors en pacients pediàtrics amb exoesquelets, s'identifiquen nombroses aplicacions potencials d'un sistema semblant en altres àrees. Aquest estudi ha contribuït a un petit avanç en la fusió dels elements tèxtils i els electrònics

In this work, different textile electrodes are assessed and a novel measurement system for their characterization is presented. Those electrodes are made of a paraffin-coated conductive yarn embroidered into a textile substrate following two distinct embroidering techniques with up to six different geometry characteristics for each one. To evaluate the sensor behaviour, the impedance has been measured by means of an LCR meter at 50¿kHz at atmospheric conditions (25¿°C and about 40% relative humidity). The results obtained were as follows. First, the application of a paraffin wax coating to the conductive yarn enhances better test results and eases the production process. Second, the proposed measurement system provides much more consistent results in comparison with other standard techniques already in use. Finally, higher densities of conductive yarn obtained lower resistance values, and so impedance, rather than other configurations., This work was supported by the Spanish Government-MICINN under Projects PID2021-124288OB-I00 and TED2021-131209B-I00., Peer Reviewed, Postprint (published version)

La monitorización de la posición en los pacientes que tienen movilidad reducida es de gran importancia en el ámbito de la salud, ya que podría suponer un gran riesgo desarrollando enfermedades como las ulceras por presión (UPP). En los últimos años se realizaron varios estudios midiendo las fuerzas que intervienen en la postura del paciente. Un problema que obstaculiza el progreso de la investigación es la dificultad para medir la fuerza de corte o fuerza transversal (shear force) en los usuarios de sillas de ruedas, en comparación con las demás. En este proyecto se desarrollará un sensor capacitivo innovador flexible con la capacidad de recuperación mecánica después de deformarse, que pretende contribuir a la prevención de úlceras por presión (PPU) en pacientes en silla de ruedas, mediante la medición de las fuerzas que surgen, y se centrará en la medición de la fuerza de corte. El proyecto se llevó a cabo inicialmente realizando un estudio de los posibles materiales a emplear, que deben ser flexibles y que se adapten a la geometría propuesta del sensor. Posteriormente, se realizó un estudio y análisis de las propuestas de posibles configuraciones para conseguir el objetivo de medir la fuerza de corte, mediante la medición de la variable de capacidad. De Los resultados de las mediciones de capacidad realizadas, se observa que tienen un comportamiento bastante lineal con el desplazamiento que tiene lugar entre los dos electrodos. Según los resultados obtenidos, el prototipo de sensor realiza las funciones que se han descrito en las especificaciones, es capaz de realizar medidas correctas y lineales en buena aproximación

A low profile textile MIMO antenna design for Industrial scientific and medical bands at 5.8 GHz is presented. The design consists of 2 embroidered antennas based on vertical and horizontal strips with a shared partial ground structure on Felt substrate. The dimensions of the designed MIMO are 50×50×1 mm3 with a permittivity of 1.2 and 0.02 loss tangent. An isolation of 18 dB between the two ports is achieved. The gain and the efficiency of the flat textile MIMO antenna are 3.64 dBi and 98%, respectively. Bending impact with different radius has been considered with a slight shift in the resonance frequency and a small reduction of gain, efficiency and isolation in the ISM band. The Envelope Correlation Coefficient (ECC) between the antennas is less than 0.01 at the operation frequency band., Peer Reviewed, Postprint (published version)

An embroidered textile UHF RFID is proposed and characterized. The TAGs are based on a ‘T-match’ structure embroidered on a polyester textile substrate with three different conductive yarns. The input impedance and read range performance has been experimentally measured. The results show that the lower the electrical resistance of the yarn, the greater the TAG read range, achieving up to 7.5 meters., Peer Reviewed, Postprint (published version)

Tesi en modalitat de compendi de publicacions, amb continguts parcialment retallats per drets de l’editor, (English) Wearable antenna sensors are a promising technology for developing new applications in the healthcare field since textiles are widely used by everyone due to the maturity of textile manufacturing. According to the last decade's market behavior, it is expected that consumers will claim smaller and more intelligent communications systems which will improve their quality of life. In this respect, wearable antenna sensor technology is one of the key implementations of the future smart clothes field and they may find their place in our daily life. Currently, the researches on wearable antenna sensors are receiving increasing interest while wearable antenna sensors on textile have less research, thus it is a novelty and motivation of this thesis. This thesis deals with challenges regarding wearable antenna sensor design, characterization, and measurements on textile. Based on the analysis of the current state of the art, there are several new research that merits to be explored, thus generating the specific objectives of this thesis. The first objective is to develop new textile antenna sensors with high performance including low profile, high sensitivity, low cost, and high durability; the second objective is to explore wearable antenna-based sensors that can be used for body signal/healthcare monitoring and communication purposes; the third objective is to test the performance of the antenna sensor in real-world scenarios, such as breathing monitoring, and the fourth objective is to develop antenna sensors that can be integrated into clothing for breathing monitoring combined with other commercial electronic components, such as Bluetooth/WIFI transmitter. For achieving the first objective, an embroidered fully textile antenna-based sensor is proposed to detect various concentrations of salt and sugar using microwave signals. Different concentrations of salt and sugar are identified through variations in frequency shifts and magnitude levels observed in reflect, (Español) Los sensores de antena portátiles son una tecnología prometedora para el desarrollo de nuevas aplicaciones en el campo de la salud, ya que los textiles son ampliamente utilizados por todos debido a la madurez de los métodos de fabricación textil. De acuerdo con el comportamiento del mercado de la última década, se espera que los consumidores reclamen sistemas de comunicaciones más pequeños e inteligentes que mejoren su calidad de vida. En este sentido, la tecnología de sensor de antena portátil es una de las implementaciones clave del futuro campo de la ropa inteligente y puede encontrar su lugar en nuestra vida diaria. Actualmente, las investigaciones sobre sensores de antena portátiles están recibiendo un interés creciente, mientras que los sensores de antena portátiles en textiles han sido sometidos a menor investigación, por lo que es una novedad y motivación de esta tesis. Esta tesis aborda los desafíos relacionados con el diseño, la caracterización y las mediciones de sensores antena portátiles. En base al análisis del estado del arte actual, hay varias investigaciones nuevas que merecen ser exploradas y que constituyen los objetivos específicos de esta tesis. El primer objetivo es desarrollar nuevos sensores de antena textil con alto rendimiento que incluyan bajo perfil, alta sensibilidad, bajo costo y alta durabilidad; el segundo objetivo es explorar sensores portátiles basados en antenas que se puedan integrarse en la ropa para propósitos de comunicación y monitoreo de señales corporales/salud; el tercer objetivo es probar el rendimiento del sensor de antena en escenarios del mundo real, como el control de la respiración, y el cuarto objetivo es desarrollar sensores de antena que se puedan integrar en la ropa para para monitorear la respiración junto con otros componentes electrónicos comerciales, como el transmisor Bluetooth/WIFI. Para lograr el primer objetivo, se propone un sensor basado en una antena totalmente textil bordado para detectar dif, Postprint (published version)

Tesi en modalitat de compendi de publicacions, amb continguts retallats per drets de l’editor, (English) Nowadays, the textile clothing industry is searching for new ways to add value to their products. Developments in textile sensors start to demonstrate their usability and possibilities when they are integrated on fabrics. The Internet of Things context pushes the companies to find new ways to obtain information from our surroundings to be able to actively react, in real-time, to the situation we are living in. For many years, the integration of sensors in textile has been regarded as inconvenient. The users do not feel comfortable to use it since the textile properties are modified. In recent years, advancement in technology and integration of conductive materials into textile materials have provided that the researchers new opportunities to integrate sensors on fabrics. Conductive yarns produced following the textile processes results in a family of yarns which are soft, flexible and conductive. The conductive material is unnoticeable by sight which is very important for the final user feeling. These conductive yarns are being used to develop conductive fabrics or patterns that do not give the feeling of being a sensor or electrically conductive. The sensors play an important role to make our daily life more comfortable and easy. But due to their certain features, conventional sensors may not be a good fit for the applications in some fields. Textile sensors rise as a new alternative tool to address the shortcomings of the conventional sensors. Textile capacitive sensors could provide a new tool to introduce sensors in fields where it could not be done previously. The advantages of the textile capacitive sensors are flexibility, long area coverage and proximity to the measured stimulus. The thesis is focused on the textile capacitive sensor development. The conductive materials, the effect of the materials on the sensor behaviour and the textile integration methods are covered over the course of the thesis. The textile capacitive sensor is based on the pe, (Español) En la actualidad, la industria de la moda está buscando nuevas formas de añadir valor a sus productos. El desarrollo en los ensores textiles integrados en los tejidos, empieza a demostrar su utilidad y posibilidades. El contexto actual de Internet de las cosas (IoT), está provocando que las compañías busquen nuevas formas de obtener información de nuestro alrededor, para así, poder reaccionar activamente, en tiempo real, a las situaciones que estamos viviendo. Durante años, la integración de sensores textiles ha sido rechazada, sobre todo por los posibles usuarios. Estos no se sentían cómodos usando tejidos con sensores integrados, debido a la modificación que estos provocaban en las propiedades de los mismos. En los últimos años, los avances en los procesos tecnológicos y la integración de materiales conductores en los material es textiles han provisto a los investigadores de nuevas oportunidades para poder integrar sensores en los tejidos. Los hilos conductores producidos mediante técnicas textiles resultan ser unos hilos suaves, flexibles y conductores. El material conductor pasa a ser indetectable visualmente, lo cual es muy importante para las sensaciones del usuario final. Estos hilos conductores son usados para desarrollar tejidos o patrones conductores que no dan la sensación de ser sensores o conductores de la electricidad. Los sensores juegan un papel muy importante a la hora de hacer nuestra vida diaria más fácil y cómoda. Pero, debido a una serie de características, los sensores convencionales no pueden ser usados en ciertas aplicaciones. Los sensores textiles aparecen como alternativa viable para responder a desventajas que pueden tener los sensores convencionales a la hora de ser integrados. Los sensores textiles pueden llegar a ser una opción para introducir sensores en nuevas aplicaciones, antes inexploradas. Las ventajas que aportan los sensores textiles son su flexibilidad, cobertura de un área amplia y la proximidad al estímulo medido. L, Postprint (published version)

This study showcases the creation of an innovative textile antenna sensor that utilizes a resonant cavity for the purpose of liquid characterization. The cavity is based on circular substrate integrated waveguide (SIW) technology. A hole is created in the middle of the structure where a pipe is used to inject the liquid under test. The pipe is covered by a metal sheath to enhance the electromagnetic field’s penetration of the tube, thus increasing the device’s sensitivity. The resonance frequency of the proposed system is altered when the liquid under test is inserted into the sensitive area of the structure. The sensing of the liquid is achieved by the measurement of its dielectric properties via the perturbation of the electric fields in the SIW configuration. The S11 measurement enables the extraction of the electromagnetic properties of the liquid injected into the pipe. Specifically, the dielectric constant of the liquid is determined by observing the resonance frequency shift relative to that of an air-filled pipe. The loss tangent of the liquid is extracted by comparing the variation in the quality factor with that of an air-filled pipe after eliminating the inherent losses of the structure. The proposed SIW antenna sensor demonstrates a high sensitivity of 0.7 GHz/¿er corresponding to a dielectric constant range from 4 to 72. To the best of our knowledge, this article presents for the first time the ability of a fully textile SIW cavity antenna-based sensor to characterize the dielectric properties of a liquid under test and emphasizes its differentiating features compared to PCB-based designs. The unique attributes of the textile-based antenna stem from its flexibility, conformability, and compatibility with various liquids., Postprint (published version)

This paper presents a mutual coupling reduction technique in a textile ultra-wideband (UWB) multiple-input–multiple-output (MIMO) antenna system implemented on a textile substrate. The compact textile UWB MIMO antenna consists of two patch antennas implemented on a felt textile substrate. The compact size and close placement of the antennas in a MIMO system cause higher mutual coupling which deteriorates the performance of the communication systems. To minimize the mutual coupling, Parasitic Elements and Defected Ground Structures are used in the designed textile UWB MIMO antenna. The MIMO antenna performed very well over almost the whole UWB frequencies ranging from 3.29¿GHz to 13.3¿GHz. The simulated and the measured parameters showed a good impedance matching with an impedance bandwidth of 133.4%. The results showed an improvement of 20¿dB isolation at certain frequencies without impacting the reflection coefficient S and the antenna impedance bandwidth. The MIMO antenna has good diversity performance parameters in terms of Envelope Correlation Coefficient (ECC), Diversity Gain, Mean Effective Gain (MEG) and radiation pattern and the results indicate that the textile antenna is suitable for UWB MIMO applications. The overall size of the antenna is 30x60¿mm2. Fully embroidered structure provides freedom of movement and comfort, so it is a good fit for Wireless Body Area Network applications., Postprint (author's final draft)

In this paper, woven wearable metamaterials are developed. For this purpose, several frequency selective surface (FSS) textile absorbers are proposed. The main structure of the FSS consists of a fabric with different patch shapes, a back ground plate (conductive layer) and a textile substrate. Firstly, the effect of the substrate used on the S-parameters and absorbance in order to detect the best substrate is analyzed. Then, once selected the best substrate, the effect of the patches’ shape on the performance of the wearable metamaterial is analyzed. It was found that the fabric that gives the best results is the one composed of 65% polyester and 35% cotton and the best patches are the cross-shaped ones. The developed FSS can be used in wearable textiles to protect the human body from microwave radiation emissions., Peer Reviewed, Postprint (author's final draft)

In this paper, a full textile capacitive woven sensor integrated over a textile substrate is presented. The sensor consists in an interdigitated capacitance prepared to measure moisture and/or presence detection. In order to evaluate the sensor response to moisture, capacitance has been measured by means of an LCR meter from 20 Hz to 20 kHz in a climatic chamber with a swept of the relative humidity (RH) from 30% to 90% at 20 °C. Subsequently, presence response is evaluated measuring the capacitance of the woven sensor meanwhile a person is sitting down and getting up. The woven sensor results demonstrate its functionality over moisture measurement where sensor capacitance changes from a minimum of 9.74 pF at 30% RH to a maximum of 2.31 uF at 90% RH. The presence detection is also demonstrated, which makes the capacitance variation change from a 10% of capacitance variation when the chair is empty, to a capacitance variation of 170% when a person is sitting on it. The adaptation of the weaving process to accomplish a fully integrated sensor provides a better repeatability than previous embroidered sensors and opens a door to being commercially produced., This work was supported by Spanish Government-MINECO under Project TEC2016-79465-R and AGAUR-UPC(2020 FI-B 00028). Agencia de Gestión de Ayudas Universitarias y de Investigación, Generalitat de Catalunya., Peer Reviewed, Postprint (published version)

This paper provides an overview of flexible and wearable respiration sensors with emphasis on their significance in healthcare applications. The paper classifies these sensors based on their operating frequency distinguishing between high-frequency sensors, which operate above 10 MHz, and low-frequency sensors, which operate below this level. The operating principles of breathing sensors as well as the materials and fabrication techniques employed in their design are addressed. The existing research highlights the need for robust and flexible materials to enable the development of reliable and comfortable sensors. Finally, the paper presents potential research directions and proposes research challenges in the field of flexible and wearable respiration sensors. By identifying emerging trends and gaps in knowledge, this review can encourage further advancements and innovation in the rapidly evolving domain of flexible and wearable sensors., This work was supported by the Spanish Government (MICINN) under Projects TED2021-131209B-I00 and PID2021-124288OB-I00., Peer Reviewed, Postprint (published version)

With the development of the healthcare field, multi-application textile tags are worth exploring. In this paper, three types of body postures are tested by a proposed textile UHF-RFID tag, including monitoring a bent knee, a bent elbow and bent back. The RSSI-angle fitting curves on the bent knee and elbow conform to quadratic function models whereas the fitting curve on the back conforms to an exponential function. Through the experimental measurements, the proposed textile UHF-RFID tag is proved to have the feasibility of monitoring the bending level of the three types of body postures by the correspondence between the RSSI and bending angles., Peer Reviewed, Postprint (published version)

The field of flexible electronics is undergoing an exponential evolution due to the demand of the industry for wearable devices, wireless communication devices and networks, healthcare sensing devices and the technology around the Internet of Things (IoT) framework. E-tex tiles are attracting the healthcare areas, amongst others, given the possibility to develop continuous patient monitoring solutions and customized devices to accommodate patient’s spe-cific needs. This review paper summarizes multiple approaches investigated in the literature for wearable/flexible resonators working as antenna-based systems, sensors and filters, with a spe-cial attention to the integration to flexible materials, especially textiles. This review manuscript provides a general overview of the flexible resonators’ advantages and drawbacks, materials, fabrication techniques and processes and applications. Finally, the main challenges and future prospects of wearable resonators are discussed., Peer Reviewed, Postprint (published version)

In this paper, a smart office chair with movable textile sensors to monitor sitting position during the workday is presented. The system consists of a presence textile capacitive sensor with different levels of activation with a signal conditioning device. The proposed system was integrated into an office chair to detect postures that could provoke musculoskeletal disorders or discomfort. The microcontroller measured the capacitance by means of a cycle count method and provided the position information in real time. The information could be analysed to set up warnings to prevent incorrect postures or the necessity to move. Five participants assumed a series of postures, and the results showed the workability of the proposed smart chair. The chair can be provided as a new tool for companies, hospitals, or other institutions to detect incorrect postures and monitor the postures of people with reduced mobility. This tool can optimise control procedures or prevent occupational risks., This work was supported by The Academy of Finland (decisions 332168 and 337861) and The Ministry of Education and Culture, Finland (Tekos project). Moreover, it was supported by the Agencia Estatal de Investigación under project PID2021-124288OB-I00 and AGAUR UPC (2020 FI-B 00028)., Peer Reviewed, Postprint (published version)

© 2023 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works., The paper presents a system for monitoring breathing patterns based on an antenna-sensor integrated into an e-textile T-shirt with a Bluetooth transmitter. The main aim of the system is to detect and monitor respiratory diseases. The sensor consists of a meander dipole antenna made of a silver-coated nylon thread attached to a compact transmitter. The respiratory signal is extracted from the received signal strength indicator (RSSI) emitted from the antenna-based sensor and detected wirelessly by a base station, which contains a computer with a receiver Bluetooth module. We analyzed the feasibility assessment of using a textile antenna-based sensor for respiratory monitoring of a female volunteer in sitting position with different breathing patterns. The experimental results showed that respiratory signals can be acquired wirelessly by the RSSI via Bluetooth, the RSSI of different breathing patterns range change from -72 dBm to -82dBm, -80dBm to -86dBm and -79dBm to -86dBm for Eupnea, Biot and Cheyne-stokes, respectively., Postprint (author's final draft)

Programa de doctorat: Doctorat en Enginyeria Electrònica

Incoming

En aquest projecte s’ha estudiat, dissenyat i simulat una sèrie d’antenes del tipus dipol destinades a funcionar sobre la banda ISM a 2,45 GHz. L’objectiu del projecte serà arribar a dissenyar una antena totalment funcional amb el software CST Studio Suite 3D EM. Aquesta antena és dissenya sobre un substrat tèxtil amb l’objectiu de ser un wearable per poder obtenir dades entre la respiració superficial i profunda d’un model humà. A més, s’han realitzat totes les simulacions necessàries per tal d’assegurar la funcionalitat i poder assegurar-ne la seguretat d’aquesta obtenint les tasses d’absorció en el cos humà (SAR). Per últim, es farà la comparació de tots els dissenys funcionals obtinguts per observar quins canvis hi ha en funció de l’antena. A dia d’avui, la tecnologia wearable la trobem molt present i en un futur promet ser tota una revolució. És més, pel que fa les antenes tèxtils la majoria estan en fase d’investigació, tot i que hi ha algun model comercial, el ventall que trobem en el mercat és reduït

Wearable technology has been getting more attention for monitoring vital signs in various medical fields, particularly in breathing monitoring. To monitor respiratory patterns, there is a current set of challenges related to the lack of user comfort, reliability, and rigidity of the systems, as well as challenges related to processing data. Therefore, the need to develop user-friendly and reliable wireless approaches to address these problems is required. In this paper, a novel, full, compact textile breathing sensor is investigated. Specifically, an embroidered meander dipole antenna sensor integrated into an e-textile T-shirt with a Bluetooth transmitter for real-time breathing monitoring was developed and tested. The proposed antenna-based sensor is designed to transmit data over wireless communication networks at 2.4 GHz and is made of a silver-coated nylon thread. The sensing mechanism of the proposed system is based on the detection of a received signal strength indicator (RSSI) transmitted wirelessly by the antenna-based sensor, which is found to be sensitive to stretch. The respiratory system is placed on the middle of the human chest; the area of the proposed system is 4.5 × 0.48 cm2 , with 2.36 × 3.17 cm2 covered by the transmitter module. The respiratory signal is extracted from the variation of the RSSI signal emitted at 2.4 GHz from the detuned embroidered antenna-based sensor embedded into a commercial T-shirt and detected using a laptop. The experimental results demonstrated that breathing signals can be acquired wirelessly by the RSSI via Bluetooth. The RSSI range change was from -80 dBm to -72 dBm, -88 dBm to -79 dBm and -85 dBm to -80 dBm during inspiration and expiration for normal breathing, speaking and movement, respectively. We tested the feasibility assessment for breathing monitoring and we demonstrated experimentally that the standard wireless networks, which measure the RSSI signal via standard Bluetooth protocol, can be used to detect hum, This work was supported by the Spanish Government-MICINN under Projects TED2021- 131209B-I00 and PID2021-124288OB-I00., Peer Reviewed, Postprint (published version)

© 2022 Elsevier. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0, Textile Ultra High Frequency (UHF, 865–868 MHz) Radio Frequency Identification (RFID) devices meet difficulties from connection of solid chips and textile antennas. In this work, three electro-textile interfaces integrated with the corresponding textile UHF-RFID antennas as the solutions are proposed and compared. The simulated and measured impedance curves of the corresponding antennas are all close and the radiation performance (realized gain) are designed to be near (about 1.4 dBi). According to the Friis formula, the simulated and measured read ranges of the interfaces with the corresponding antennas in air are obtained (all above 4.5 m). For reliability validation, mixed use feasibility tests are implemented and the results show the read ranges of each interface used on other two designs have tolerable read range decrease (< 2 m but all above 3.41 m).In addition, the read ranges of the designs on body are all above 2.05 m. Due to the small sizes of the interfaces, stable performance on body and good reliability, the proposed interfaces solutions are proved feasible., Peer Reviewed, Postprint (author's final draft)

© 2022 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works., Ultra High Frequency (UHF, 865-868 MHz) Radio Frequency Identification (RFID) devices are expected to be implemented in many health-caring areas. In this paper, we present three progressive designs of textile UHF-RFID antennas on surgical masks using a function-extensible integrated circuit (IC) chip (Rocky 100). The simulated and measured resonance curves of the designs all match well (|S11| < -20 dB at 868 MHz) and the maximum realized gain are improved progressively in order to overcome the difficulty of the chip low sensitivity and increase the maximum read range. The best type (Design 3) is selected and its read range measured by the RFID reader (M6e kit) can reach 2.5 m in air. In addition, several reliability validation measurements are performed, such as bending and skin contact, and maximum read range can reach 1.1 m considering the on-body worn worst case. The proposed Design 3 allows common use as a tag for tracking or safe distance alert under an epidemic situation. Alternatively, for the used function-extensible chip, the design can be applied to many different types of sensors for various application scenarios., This work was supported in part by Spanish Government-MINECO under Project TEC2016-79465-R, and China Scholarship Council under Grant No.201908440233., Peer Reviewed, Postprint (author's final draft)

In this work, several fabrics with different composition and structure have been used as the substrate for the production of wearable textile-embroidered dipole antennas. The performance of the antennas has been determined by measuring their resonance frequency, return loss and bandwidth. To determine their durability as wearable fabrics, the performance has been assessed before and after subjecting the antennas to washing and abrasion cycles. The results revealed that the woven fabrics presented a good washing fastness, even in fabrics having elastic fibers or low-crimp structures. In all cases, a good performance of the antennas was maintained after 30 washing cycles. For the abrasion cycles, the substrates with higher stability (measured as the crimp ratio) presented a higher wear fastness, whereas a higher variability was observed for the substrates with lower stability, Postprint (author's final draft)

A woven capacitive sensor is presented as a novel automotive seat occupancy sensor. The woven capacitive sensor is developed as a response to one of the most difficult challenges that the automotive sector has faced the past few years: seat occupancy sensor false positives. The designed sensor demonstrates the error-free sitting detection of a person by detecting the change of the permittivity around it, providing a distinction between a person and an object with the same weight., This research was funded by Spanish Government “Ministerio de ciencia e innovacion” PID2021 124288OB I00 and AGAUR 2020FI-B 00028., Peer Reviewed, Postprint (published version)

© 2022 Elsevier. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0, In this paper we present the design and the validation of a novel fully embroidered meander dipole antenna-based sensor integrated into a commercially available T-shirt for real-time breathing monitoring using the technique based on chest well movement analysis. The embroidered antenna-based sensor is made of a silver-coated nylon thread. The proposed antenna-sensor is integrated into a cotton T-shirt and placed on the middle of the human chest. The breathing antenna-based sensor was designed to operate at 2.4 GHz. The sensing mechanism of the system is based on the resonant frequency shift of the meander dipole antenna-sensor induced by the chest expansion and the displacement of the air volume in the lungs during breathing. The resonant frequency shift was continuously measured using a Vector Network Analyzer (VNA) to a remote PC via LAN interface in real-time. A program was developed via Matlab to collect respiration data information using a PC host via LAN interface to be able to transfer data with instrumentation over TCP/IP. The measurements were carried out to monitor the breathing of a female volunteer for various positions (standing and sitting) with different breathing patterns: eupnea (normal respiration), apnea (absence of breathing), hypopnea (shaloow breathing) and hyperpnea (deep breathing). The measured resonance frequency shift to 2.98 GHz, 3.2 GHz and 2 GHz for standing position and 2.84 GHz, 2.95 GHz and 2.15 GHz for sitting position, for eupnea, hyperpnea and hypopnea, respectively. The area of the textile sensor is 45 x 4.87 mm2 , reducing the surface consumtion significatively with regard to other reported breath wearable sensors for health monitoring., This work was supported by the Spanish Government MINECO under project TEC2016-79465-R., Peer Reviewed, Postprint (author's final draft)

©2022 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works., This paper presents an embroidered textile frequency-splitting microwave sensor based on a pair of identical stepped-impedance resonators (SIRs) loading a microstrip transmission line. The sensor is implemented by means of conductive threads. The sensing region of the proposed structure is the capacitive square patch of one of the SIRs. If such region is kept unaltered, the structure is symmetric, and the frequency response (transmission coefficient) exhibits a single transmission zero. However, if symmetry is broken (e.g., through liquid absorption in the sensing region), the frequency response of the proposed sensor exhibits two transmission zeros (frequency splitting). The difference (in frequency and magnitude) between such zeros (or notches) is intimately related to the dielectric properties of the absorbed liquids to be sensed / detected. The proposed sensing structure is applied to the detection of deionized (DI) water absorption, and to the quantification of the number of DI water drops. The maximum measured sensitivity is found to be 2.70 MHz /µl and 0.03 dB /µl for the incremental frequency and incremental magnitude of the notches., This work was supported by MICIIN-Spain (projects PID2019-103904RB-I00, TEC2016-79465-R, and PDC2021-121085-I00),Generalitat de Catalunya (project 2017SGR-1159), Institució Catalana de Recerca i Estudis Avançats (who awarded Ferran Martín), and by FEDER funds., Peer Reviewed, Postprint (author's final draft)

Tesi en modalitat de compendi de publicacions, amb una secció retallada per drets de l'editor. In reference to IEEE copyrighted material which is used with permission in this thesis, the IEEE does not endorse any of Universitat Politècnica de Catalunya's products or services. Internal or personal use of this material is permitted. If interested in reprinting/republishing IEEE copyrighted material for advertising or promotional purposes or for creating new collective works for resale or redistribution, please go to http://www.ieee.org/publications_standards/publications/rights/rights_link.html to learn how to obtain a License from RightsLink., Radio frequency identification over measurable ultra-high frequency textile substrates (UHF-RFID) is a promising technology to develop new applications in the field of health and the Internet of Things (IOT), due to the massive use of fabrics and the technological maturity of embroidery techniques. This thesis is the result of a compendium of publications on this topic. First, as a result of the analysis of the state of art, a systematic review entitled 'Wearable textile UHF-RFID sensors: A systematic review' has been published. The thesis aims to improve research on UHF-RFID textile-based sensor technology. Thanks to the analysis of the state of art, three novel research objectives have been set that are worth exploring. The first is to study novel detection functions for textile UHF-RFID based sensor technology; the second is to find a connection/interface solution between textile antennas and integrated circuit (IC) chips and the third is to reduce the costs of such technology to promote future commercial applications. To contextualize the thesis, it includes the necessary theoretical fundamentals and the manufacturing and characterization methods used during it. As a result of the work derived from the first objective, a scientific article entitled “Textile UHF-RFID Antenna Sensor for Measurements of Sucrose Solutions in Different Levels of Concentration” has been published. In this work, a textile UHF-RFID tag with two detection positions is proposed for sucrose solution measurements. The two detection positions with the different detection functions show good performance and can offer two options for future full applications. In addition, another scientific article entitled “ Textile UHF-RFID Antenna Embroidered on Surgical Masks for Future Textile Sensing Applications” has been published to support the first objective. The inspiration for this work came from the current pandemic situation. This work develops three progressive designs of textile UHF-RFID anten, La identificación por radiofrecuencia sobre substratos textiles de ultra alta frecuencia (UHF-RFID) con capacidad de medida es una tecnología prometedora para desarrollar nuevas aplicaciones en el campo de la salud y el Internet de las cosas (IOT), debido a la masiva utilización de los tejidos y a la madurez tecnológica de las técnicas de bordado. Esta tesis es el resultado de un compendio de publicaciones sobre dicha temática. En primer lugar, como resultado del análisis del estado del arte se ha publicado una revisión sistemática titulada 'Wearable textile UHF-RFID sensors: A systematic review'. La tesis tiene como objetivo mejorar la investigación sobre la tecnología de sensores basada en textiles UHF-RFID. Gracias al análisis del estado del arte se han fijado tres objetivos de investigación novedosos que vale la pena explorar. El primero es estudiar funciones de detección novedosas para la tecnología de sensores basada en UHF-RFID textiles; el segundo es encontrar una solución de conexión/interfaz entre antenas textiles y chips de circuito integrado (IC) y el tercero es la reducción de costes de dicha tecnología para promover futuras aplicaciones comerciales. Para contextualizar la tesis, ésta incluye los fundamentos teóricos necesarios y los métodos de fabricación y caracterización utilizados durante la misma. Como resultado del trabajo derivado del primer objetivo, se ha publicado un artículo científico titulado “Textile UHF-RFID Antenna Sensor for Measurements of Sucrose Solutions in Different Levels of Concentration”. En este trabajo, se propone una etiqueta UHF-RFID textil con dos posiciones de detección para mediciones de solución de sacarosa. Las dos posiciones de detección con las diferentes funciones de detección muestran un buen rendimiento y pueden ofrecer dos opciones para futuras aplicaciones completas. Además, se ha publicado otro artículo científico titulado "Textile UHF-RFID Antenna Embroidered on Surgical Masks for Future Textile Sensing Applica, Postprint (published version)

© 2022 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works., Electro-textile Ultra High Frequency (UHF, 865–868 MHz) Radio Frequency Identification (RFID) devices have great potential to be explored as sensors due to the features of fabric materials. In this work, an electro-textile UHF-RFID compression sensor base on T-match structure with a corresponding interface are developed and evaluated for two application scenarios. For accurate textile UHF-RFID antenna design and maximize the read range, the impedance of the electro-textile based on snap buttons is modelled and characterized an a measured read range of 5.22m is experimentally obtained. If the distance of the RFID reader and RFID sensor remain constant at 1 m. The experimental results show that RSSI range change from -42 dBm to -58 dBm as a quadratic function in terms of the knee angle bending and from -45 dBm to -40 dBm during expiration and inspiration phase when the sensor is located on the chest, which validated the usefulness of the proposed sensor., This work was supported in part by Spanish Government-MINECO under Project TEC2016-79465-R and China Scholarship Council under Grant No.201908440233., Peer Reviewed, Postprint (author's final draft)

This paper presents an experimental abrasion analysis of textile capacitive sensors based on Martindale test. The textile sensor is manufactured with a well-known woven technology where some yarns are replaced by electrical conductive yarn. Specifically, two types of conductive yarns were used to compare the abrasion behaviour respect to conventional fabrics and the impact of abrasion on sensors functionality. The results show that the integration of conductive yarn on fabric don’t reduce the fabric lifetime and moreover the sensing behaviour remains unalterable during the lifetime of the textile., This work was supported by Spanish Government-MINECO under Project TEC2016-232 79465-R and AGAUR-UPC (2020 FI-B 00028)., Peer Reviewed, Postprint (published version)

Este trabajo consiste en el estudio, diseño, fabricación y medición de un sensor resistivo tridimensional en tejido plegable. Es un proyecto de investigación sobre el desarrollo de este tipo novedoso de sensores y sus aplicaciones centrándose en la medición de la respiración. Se incluyen estudios sobre los sensores y la tecnología Wearable a nivel general. Para después explicar la parte principal del proyecto que es el desarrollo, diseño y optimización del sensor para posteriormente hacer las mediciones y comprobaciones para estudiar su comportamiento y posibles usos

El presente Trabajo Final de Máster tiene como objetivo el estudio, diseño, simulación, impresión y medición de un sensor tridimensional en textil plegable basado en un resonador mediante tecnología microstrip. El desarrollo e implementación de estos dispositivos wereable ofrecen un abanico de aplicaciones muy amplio, entre ellas la detección de posición y/o postura de una persona, la obtención de datos métricos o señales vitales, la interface con computadoras, la integración en aplicaciones comerciales, entre otras. Se trata de un proyecto de investigación pionero en el desarrollo de esta clase de sensores no disponibles actualmente en el mercado, en colaboración con las universidades UdK de Berlín (Alemania) y Loughborough University (Reino Unido)

A novel wearable Frequency Selective Surface (FSS) created using fabric materials capable of blocking electromagnetic radiation around the frequency of 10.64 GHz (X Microwave frequency band) is presented in this paper. Two different unit cell shapes are tested: embroidered metal yarn squares and hexagons. A cotton fabric with permittivity 1.9 and thickness 0.4 mm is used as a substrate. The proposed design is validated by comparison of 3 D electromagnetic simulations and measurements. The obtained results correspond to a maximum absorptivity of 99.23% at 10.63 GHz for the simulation using a square as unit cell, whereas the simulations using hexagons led to a maximum in absorptivity of 99.94% at 10.68 GHz. Experimental results, at their turn, showed maximums of 98.39% for the squares and 98.00% for the hexagons, both at 10.46 GHz. So, results showed that the textile was actually offering a high degree of electromagnetic shielding, increasing the safety for civil and occupational exposures to electromagnetic radiation. In this case, this protection is offered at the microwave frequencies, used especially for telecommunications Earth-satellite which is in the range considered as a potential risk by the WHO (World Health Organization)., This work was supported by the Spanish Government MINECO under Project TEC2016-79465-R., Peer Reviewed, Postprint (author's final draft)

©2021 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works., In this paper a wearable system with a sensor embroidered on a textile substrate to detect urine leaks is presented. The system consists of a moisture textile capacitive sensor together with the signal conditioning and its wireless transmission to the cloud. The proposed system has been integrated on underwear and hospital sheet to detect the urine leakage on the diaper users and critical ill patient, respectively. The methodology used by the microcontroller to measure the sensor value is a charge/discharge method. The information is visualised through a computer or smartphone, where can be seen the current state of the sensor. The system has a warning set up to communicate any urine leakage. The experimental results show the functionality of the proposed system which could supply a new tool to hospitals, nursing homes or other institutions to detect when the patient diaper or sheet need to be removed. This tool can optimise the hospital protocol and improve the patient quality of life., This work was supported by Spanish Government-MINECO under Project TEC2016-79465-R and AGAUR-UPC(2020 FIB 00028)., Peer Reviewed, Postprint (author's final draft)

In this paper, the utilization of common fabrics for the manufacturing of e-textile metamaterial is investigated. The proposed design is based on a transmission line loaded with split-ring resonators (SRRs) on a cotton substrate for filter signal application. The proposed design provides a stop band between 2.7 GHz and 4.7 GHz, considering a four stage SRR topology. Experimental results showed stop band levels higher than -30 dB for the proposed compact embroidered metamaterial e-textiles. The validated results confirmed embroidery as a useful technique to obtain customized electromagnetic filter properties, such as transmitted signal filtering and control, on wearable tech device applications., This work was supported by the Ministry of Economy, Industry and Competitiveness under project TEC2016-79465-R., Peer Reviewed, Postprint (published version)

This paper addresses the design and fabrication of an embroidered textile RFID tag antenna. The main feature of this design is that we have embroidered an RFID chip on the textile support which avoids the use of metallic wires or soldering. The modeled equivalent circuit of the tag is presented to get physical insight into RFID tag antenna design. The detailed results given in this paper include the effect of the bending and the human body proximity on the antenna performance. It is shown that the bending does not introduce a conspicuous effect on the tags read range while the dissipative characteristics of the human body cause a gain and read range reduction. The proposed design may find applications in wearable devices dedicated to health monitoring applications., Peer Reviewed, Postprint (author's final draft)

Recently, researchers have adapted Bioelectrical Impedance Analysis (BIA) as a new approach to objectively monitor wounds. They have indicated various BIA parameters associated to specific wound types can be linked to wound healing through trend analysis relative to time. However, these studies are conducted using wet electrodes which have been identified as possessing several shortcomings, such as unstable measurements. Thus, the adaption of e-textile electrodes has become an area of interest in measuring biosignals. E-textile electrodes are known to possess a significantly large polarization impedance (Zp) that potentially influences these biosignal measurements. In this study we aim to identify the suitability of e-textile electrodes to monitor wounds using BIA methodologies. By adapting suggested methodologies conducted in-vivo from previous studies, we used an ex-vivo model to observe the behaviour of e-textile electrodes relative to time. This was compared to common clinical wet electrodes, specifically Ag/AgCl. The objective of this study was to identify the BIA parameters that can be used to monitor wounds with e-textile electrodes. By analysing the BIA parameters relative to time, we observed the influence of Zp on these parameters., Peer Reviewed, Postprint (author's final draft)

In this paper, a feasibility study of a microwave antenna-based sensor is proposed for in vitro experiments for monitoring blood glucose levels. The proposed device consists of a square-ring incorporated within a fully textile monopole antenna to absorb and sense different glucose concentrations, covering patients with different diabetic conditions. The designed antenna-sensor is optimized to operate at 2.4 GHz. The sensing principle is based on the resonance frequency shift of the reflection response of the antenna-based sensor under different glucose levels. The experiments were carried out with blood mimicking by means of aqueous solutions, using D(+)- glucose/water in different concentrations for various diabetic conditions of type-2 diabetes. The performance of the embroidered antenna-based sensor is characterized and validated using a convenient setup for in vitro measurements. The results demonstrated the ability of the proposed antenna-based sensor to cover all the glucose levels of the diabetes range, including hypoglycemia (10–70 mg/dL), normoglycemia (80–110 mg/dL) and hyperglycemia (130–190 mg/dL) with a sensitivity of 350 kHz/(mg/dL). Besides its ability to detect different glucose concentrations of various diabetic conditions, the proposed antenna-sensor presents diverse features such as a simplistic design, compact size, wearability and low cost. The proposed textile device demonstrates a proof of concept for efficient in vitro blood glucose level measurements and diagnostics of diabetes., This work was supported by the Spanish Government-MINECO under Projects TEC2016- 79465-R., Peer Reviewed, Postprint (published version)

In this paper, a method to develop embroidered textile strain resistive sensors is presented. The method is based on two overlapped zigzag conductive yarn patterns embroidered in an elastic textile. To demonstrate the functionality of the proposed configuration, a textile sensor embroidered with a conductor yarn composed of 99% pure silver-plated nylon yarn 140/17 dtex has been experimentally characterised for an elongation range from 0% to 65%. In order to show the sensor applicability, a second test with the sensor embroidered in a knee-pad has been done to evaluate the flexion knee angle from 180° to 300°. The experimental results show the usefulness of the proposed method to develop fabric strain sensors that can help to manufacture commercial applications on the healthcare sector., This work was supported by Spanish Government-MINECO under Project TEC2016-79465-R and AGAUR-UPC(2020 FI-B 00028)., Peer Reviewed, Postprint (published version)

© 2021 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works., This paper presents a monopole antenna-based sensor for measuring different amounts and concentrations of salt and sugar in water. The proposed antenna sensor consists of a textile monopole antenna with circular-ring and partial ground plane. It is implemented by means of embroidery on a felt textile substrate and it resonates at 2.4 GHz. The textile substrate can absorb liquids through the sensing area incorporated within the monopole antenna structure. Therefore, the substrate dielectric properties are changed according to the liquid properties of the absorbed solution. The proposed antenna sensor uses microwave signals to track different amount and concentrations of salt and sugar in terms of the magnitude of the return loss and resonance frequency shift. The measurements are recorded and compared before and after applying different solutions. The rinsing reliability of the proposed antenna sensor has been also studied. The proposed antenna sensor demonstrates a high sensitivity of 800 MHz/mL with a good correlation with the linear fit ( R2=0.9737 ) and 550 MHz/mL with linear response ( R2=0.9135 ) for 5% salt and sugar concentration solutions, respectively. To the best of our knowledge, this article demonstrates for the first time the capability of a fully-textile antenna sensor to detect different amounts and concentrations of salt and sugar using microwave signals., This work was supported by the Spanish Goverment MINECO under Project TEC2016-79465-R., Peer Reviewed, Postprint (author's final draft)

With the trend of textile antennas development, ultra high frequency (UHF, 865–868 MHz) radio frequency identification (RFID) devices using textile materials are expected to be developed in many areas for replacing or simplifying some complex RFID devices on a PCB. In this paper, we present a textile UHF-RFID tag with two sensing positions ('radiation parts' and 'loop part') for exploring the feasibility of sucrose solutions measurements and the relationship between variables of the proposed design and the sucrose solutions. The simulated and measured resonance curves of the designs both match well (-20 dB in the simulation and -15.8 dB in the measurement at 868 MHz) and the read range measured by the RFID reader (M6e kit) is 1.71 m in air. Before the tests by the solutions on the proposed designs, a test board is developed as a preparation work for confirming the relative dielectric constants of the sensing substrate area in the real measurements. Compare the results of the simulation and the real tests, the proposed design shows good feasibility by comparing the simulated and measured results in confirmed relative dielectric constants. Moreover, its two sensing positions have different sensing features. The sensing 'radiation parts' position shows a stable frequency operation performance but sensing range is from 1.71 m (dry) to 2.3 m, while the sensing 'loop part' position has a wide sensing range from 0.4 m to 1.71 m (dry) but a lower frequency operation performance., This work was supported by Spanish Government-MINECO under Project TEC2016- 79465-R and China Scholarship Council No.201908440233., Peer Reviewed, Postprint (author's final draft)

In this paper, a textile UHF-RFID tag antenna at 915 MHz based on a T-match dipole loaded with circular patch on a felt fabric substrate is presented and discussed. In addition, the bending impact on the read range is analyzed by means of full 3D electromagnetic simulations. The bending analysis results indicate that the proposed textile tag can be used under both, concave and convex bending with a reduction of read range lower than 10 % in all cases. These results confirm that the proposed UHF-RFID tag is a useful design in application where the devices can be deformed, such as wearable applications., Postprint (published version)

Accés restringit a part del contingut per motius de confidencialitat., En la actualidad existen wearables capaces de medir datos biométricos y/o otros parámetros con el fin de controlar y mejorar el rendimiento deportivo, pero éstos son, en su gran mayoría, relojes y pulseras conectados a dispositivos móviles. Los textiles, en cambio, apuntan a ser excelentes sustratos para la integración de estos dispositivos, ya que se sitúan muy cerca del cuerpo de una forma no intrusiva, permitiendo una distribución precisa de los sensores. Las prendas que integran componentes electrónicos en el tejido son considerados Smart Textiles, si éstas cuentan con un mínimo nivel de integración de estos componentes. En este proyecto se ha querido estudiar la viabilidad de un producto de estas características, de lo que se considera un Smart Sport Textile. Es decir una prenda técnica deportiva que integre un determinado número de sensores, que aporten cierta información de interés para el usuario. Para ello, el trabajo se ha dividido en dos fases principales, la fase de investigación y la fase de desarrollo de la propuesta. En la primera fase, se ha buscado información sobre el estado del arte, productos similares a lo que se quiere plantear, esto incluye ver qué sensores y otras tecnologías han integrado, cómo las han integrado y con qué objetivo. Además se han estudiado otros puntos relevantes, como el público objetivo de éstos y productos y el precio de venta al público. A partir de ésta primera búsqueda, se ha realizado una segunda búsqueda, esta vez para encontrar sensores y otros componentes electrónicos para medir y parametrizar datos biométricos, que se puedan integrar en prendas. Finalmente se ha buscado también diferentes métodos de integración de sensores y otros componentes electrónicos en prendas. A partir de la información recolectada en la fase de investigación, se ha realizado una conceptualización de una propuesta de producto. Para ello, se han determinado los requerimientos del producto, se han realizado dinámicas para recoger ideas a parti

Les comunicacions sense fils estan a l'ordre del dia i el número d’aplicacions pel seu ús augmenta cada vegada més. Gran part dels productes electrònics disponibles al mercat estant incorporant comunicacions sense fils per connectar-se a la xarxa a través de Wifi. En molts casos l’usuari pot interactuar amb aquests aparells des de una aplicació en el seu telèfon mòbil. En aquest document s’exposa la possibilitat de utilitzar antenes low cost i respectuoses amb el medi ambient per a aquestes finalitats. Recentment, i cada vegada més, s’està estudiant la possibilitat de utilitzar paper com a substrat per a diferents tipus d’antenes. El paper presenta propietats desitjables com flexibilitat i versatilitat així com el fet de ser respectuós amb el medi ambient i fàcil de produir. La tècnica usada per dipositar l’antena sobre el paper és la impressió ink-jet. Aquesta tècnica consisteix en imprimir la geometria de l’antena en tinta metàl·lica sobre el substrat. Al llarg del treball es proposen tres dissenys diferents d’antenes escollides de la literatura i se n’estudia el funcionament. D’aquestes tres antenes dues son seleccionades segons criteris relacionats amb el funcionament i mètodes de producció. Les antenes seleccionades son sotmeses a diferents modificacions que n’afecten el funcionament. Les modificacions van encarades a caracteritzar-ne el funcionament segons la geometria del circuit emissor de l’antena i segons el gruix del substrat. Les modificacions de la geometria del circuit tenen en compte les corrents a la superfície de l’antena durant el seu funcionament. Aquestes corrents mostren en la geometria de l’antena les parts que estan més excitades i les que, al contrari, generen pèrdues. En tots els casos s’ha modificat la geometria reforçant el camí de màxima excitació o traient material de les zones menys excitades. En aquest aspecte la tècnica ink-jet presenta un avantatge significatiu ja que permet la impressió de geometries que son inabastables mitjançant

El present projecte es basa en la investigació del sistema actual de localització de víctimes per allaus anomenat RECCO, amb la intenció de facilitar i augmentar el numero de rescats amb èxit davant d’un allau. El principal objectiu d’aquest projecte es aconseguir una antena sense alimentació externa capaç de rebre un senyal en 0,9 GHz i transmetre’l en 1.8GHz per tal de que l’equip de rescat sigui capaç de localitzar a la víctima. El treball final de grau es dividirà en tres parts diferenciades. La primera part consistirà en realitzar un estudi intensiu de les solucions actuals de mercat així com de les diferents antenes existents avui en dia. La segona part del projecte consistirà en l’estudi de les variables i materials necessaris per dur a terme el disseny del prototip que volem fabricar durant el projecte. La tercera i ultima part del projecte consisteix en la simulació i optimització de la antena i en la obtenció de resultats experimentals. Per a dur a terme aquest projecte serà necessari utilitzar el software CST Studio així com el AWR microwave office

El artículo caracteriza a nivel estructural, morfológico y térmico tres muestras distintas de óxido de grafeno comerciales (AGO, EGO y CGO) obtenidas mediante el método Hummers, las cuales han sido posteriormente reducidas (ArGO, ErGO y CrGO). Los resultados obtenidos demuestran que las muestras AGO y EGO son estructuralmente muy parecidas mientras que la muestra CGO es totalmente distinta. Los resultados de las muestras reducidas ponen de manifiesto que la estructura inicial del óxido de grafeno es determinante en el comportamiento térmico. El análisis morfológico mediante SEM indica que los GOs con mayor dispersión de grupos oxidados, son los que presentan una estructura laminar más precisa durante el proceso de reducción. La reducción de las muestras con baja dispersión de los grupos oxidados define estructuras menos laminares y más carbonáceas, Postprint (published version)

In this work, an embroidered textile moisture sensor is proposed and characterized with three different fabric substrates. The sensors are based on a capacitive interdigitated structure embroidered on a textile substrate with a conductive yarn. The performance of three different type of substrates has been addressed. In order to evaluate the sensor behavior, the impedance of the sensor has been measured by means of an LCR meter from 20 Hz to 200 kHz on a climatic chamber with a sweep of the relative humidity from 30% to 80% at 20ºC. The results show that the fabric substrate defines the electrical properties of the sensor due to both, the substrate permittivity and size yarn thickness increase. This sensor dependence determines the optimum substrate to be used to develop wearable applications for moisture measurement., Postprint (author's final draft)

Textile radio-frequency identification operating in ultra-high frequency (UHF-RFID) sensors based on different scenarios are becoming attractive with the forthcoming internet of things (IoT) era and aging society. Compared with conventional UHF-RFID sensors, textile UHF-RFID sensors offer the common textile features, light weight, washability and comfort. Due to the short time and low level of development, researches on the integration of textile UHF-RFID techniques and textile sensing techniques are not flourishing. This paper is motivated by this situation to identify the current research status. In this paper, we provide a systematic review of the fundamentals of textile UHF-RFID sensors techniques, materials, the brief history and the state-of-the-art of the scenario-based development through detailed summary and analysis on the achievements from the starting year of 2004 to the present time. Moreover, according to the analysis, we give a proposal of the future prospects in several aspects, including the new materials and manufacturing processes, machine learning technology, scenario-based applications and unavoidable reliability., This work was supported by Spanish Government-MINECO under Project TEC2016-79465-R and ChinaScholarship Council No. 201908440233., Peer Reviewed, Postprint (published version)