Electromagnetic Waves

This volume is based on the contributions of several authors in electromagnetic waves propagations. Several issues are considered. The contents of most of the chapters are highlighting non classic presentation of wave propagation and interaction with matters. This volume bridges the gap between physics and engineering in these issues. Each chapter keeps the author notation that the reader should be aware of as he reads from chapter to the other

Microwave Dielectrometry Adapted to Environments

Tesis por compendio[ES] La permitividad es una propiedad física de los materiales que describe su comportamiento en presencia de un campo electromagnético. Los sensores de microondas pueden desempeñar un papel esencial en las tareas de detección, supervisión o control de procesos, ya que algunos parámetros fisicoquímicos de los materiales producen cambios medibles en las propiedades dieléctricas. Además, la tecnología de calentamiento por microondas está adquiriendo una relevancia creciente para la transición ecológica y la descarbonización de los procesos industriales, y la permitividad es el parámetro esencial para el desarrollo exitoso de estos nuevos procesos. La permitividad depende de muchos factores, por lo que los métodos de medición de la permitividad deben adaptarse a las necesidades del material y del entorno de medición. El número de aplicaciones que requieren la monitorización o medida de las propiedades dieléctricas, las altas dependencias de esta magnitud bajo diferentes condiciones, y la necesidad de poner esta tecnología al alcance de un usuario más amplio y menos especializado, justifican el desarrollo de este trabajo. Esta tesis pretende desarrollar nuevos dispositivos para la monitorización y caracterización de dieléctricos adaptados a diferentes entornos, cubriendo un amplio rango de formatos, formas y propiedades de los materiales. Las dos primeras publicaciones incluidas en la tesis describen dos enfoques diferentes para abordar las mediciones de permitividad. El primer artículo describe un instrumento versátil, autónomo y fácil de usar para medir la permitividad de materiales dentro de tubos. El diseño de la cavidad logró una excelente sensibilidad, y el estudio de la red de acoplamiento permitió la caracterización de materiales de pérdidas bajas, moderadas y altas con una misma configuración. Este dispositivo incluye un reflectómetro vectorial portátil propio, lo que lo hace portátil y asequible. Las características del instrumento desarrollado permiten un uso sencillo por parte de personal no especializado y proporcionan versatilidad en muchas situaciones. La segunda publicación presenta el diseño específico de una sonda coaxial de extremo abierto con una mayor sensibilidad para determinar la permitividad de productos alimenticios de altas pérdidas en función de la temperatura a frecuencias de RF. Este artículo destaca la importancia de seleccionar la técnica de medición más adecuada, adaptada al entorno y a las particularidades del material, para la determinación apropiada de la permitividad. Los dos artículos siguientes describen el desarrollo y la utilización de un microscopio de microondas de campo cercano con resolución micrométrica para determinar mapas de permitividad de materiales planos heterogéneos a frecuencias de microondas. En ambos trabajos se describen los diferentes elementos que componen el instrumento del microscopio y las técnicas de análisis para determinar los valores de permitividad a partir de las medidas de los parámetros de la resonancia. En el primer trabajo se empleó por primera vez la tecnología de microondas en aplicaciones contra la falsificación, obteniendo la marca dieléctrica de la marca de agua de un billete. Además, este estudio demostró la capacidad de la energía de microondas para detectar marcas ocultas detrás de capas dieléctricas o metálicas, lo que abre nuevas posibilidades para el desarrollo de elementos de seguridad ópticamente opacos e imposibles de rastrear por medios ópticos. El segundo estudio demuestra la versatilidad de este sistema para determinar las propiedades dieléctricas de materiales planos heterogéneos midiendo la respuesta dieléctrica de especímenes de roca. Los métodos desarrollados en esta tesis aumentan la cartera de sistemas de caracterización dieléctrica y pueden ayudar a una amplia gama de sectores científicos e industriales en las tareas de monitorización y caracterización dieléctrica, haciendo estos trabajos más cómodos y accesibles.[CA] La permitivitat és una propietat física dels materials que descriu el seu comportament en presència d'un camp electromagnètic. Els sensors de microones poden exercir un paper essencial en les tasques de detecció, supervisió o control de processos, ja que alguns paràmetres fisicoquímics dels materials produeixen canvis mesurables en les propietats dielèctriques. A més, la tecnologia de calfament per microones està adquirint una rellevància creixent per a la transició ecològica i la descarbonització dels processos industrials, i la permitivitat és el paràmetre essencial per al desenvolupament reeixit d'aquests nous processos. La permitivitat depén de molts factors i, per tant, els mètodes de mesurament de la permitivitat han d'adaptar-se a les necessitats del material i de l'entorn de mesurament. El nombre d'aplicacions que requereixen el monitoratge o mesura de les propietats dielèctriques, les altes dependències d'aquesta magnitud sota diferents condicions, i la necessitat de posar aquesta tecnologia a l'abast d'un usuari més ampli i menys especialitzat, justifiquen el desenvolupament d'aquest treball. Aquesta tesi pretén desenvolupar nous dispositius per al monitoratge i caracterització de dielèctrics adaptats a diferents entorns, cobrint un ampli rang de formats, formes i propietats dels materials. Les dues primeres publicacions incloses en la tesi descriuen dos enfocaments diferents per a abordar els mesuraments de permitivitat. El primer article descriu un instrument versàtil, autònom i fàcil d'usar per a mesurar la permitivitat de materials dins de tubs. El disseny de la cavitat va aconseguir una excel·lent sensibilitat, i l'estudi de la xarxa d'acoblament va permetre la caracterització de materials de pèrdues baixes, moderades i altes amb una mateixa configuració. Aquest dispositiu inclou un reflectòmetre vectorial portàtil propi, la qual cosa el fa portàtil i assequible. Les característiques de l'instrument desenvolupat permeten un ús senzill per part de personal no especialitzat i proporcionen versatilitat en moltes situacions. La segona publicació presenta el disseny específic de una sonda coaxial d'extrem obert amb una major sensibilitat per a determinar la permitivitat de productes alimentaris d'altes pèrdues en funció de la temperatura a freqüències de RF. Aquest article destaca la importància de seleccionar la tècnica de mesurament més adequat, adaptada a l'entorn i a les particularitats del material, per a la determinació apropiada de la permitivitat. Els dos articles següents descriuen el desenvolupament i la utilització d'un microscopi de microones de camp pròxim amb resolució micromètrica per a determinar mapes de permitivitat de materials plans heterogenis a freqüències de microones. En tots dos treballs es descriuen els diferents elements que componen l'instrument del microscopi i les tècniques d'anàlisis per a determinar els valors de permitivitat a partir de les mesures dels paràmetres de la ressonància. En el primer treball es va emprar per primera vegada la tecnologia de microones en aplicacions contra la falsificació, obtenint la marca dielèctrica de la marca d'aigua d'un bitllet. A més, aquest estudi va demostrar la capacitat de l'energia de microones per a detectar marques ocultes darrere de capes dielèctriques o metàl·liques, la qual cosa obri noves possibilitats per al desenvolupament d'elements de seguretat òpticament opacs i impossibles de rastrejar per mitjans òptics. El segon estudi demostra la versatilitat d'aquest sistema per a determinar les propietats dielèctriques de materials plans heterogenis mesurant la resposta dielèctrica d'espècimens de roca. Els mètodes desenvolupats en aquesta tesi augmenten la cartera de sistemes de caracterització dielèctrica i poden ajudar a una àmplia gamma de sectors científics i industrials en les tasques de monitoratge i caracterització dielèctrica, fent aquests treballs més còmodes i accessibles.[EN] Permittivity is a physical property of materials describing their behavior in the presence of an electromagnetic field. Microwave sensors can play an essential role in detecting, monitoring, or process control tasks as some physicochemical parameters of materials produce measurable changes in dielectric properties. Besides, microwave heating technology is gaining increasing relevance for the ecological transition and decarbonization of industrial processes, and permittivity is the essential parameter for the successful development of these new processes. Permittivity depends on many factors and thus, permittivity measurement methods must be adapted to the needs of the material and the measurement environment. The number of applications that require the monitoring or measurement of dielectric properties, the high dependencies of this magnitude under different conditions, and the need to make this technology available to a broader and less specialized user justify the development of this work. This thesis aims to develop new devices for the monitoring and characterization of dielectrics adapted to different environments, covering a wide range of materials' formats, shapes, and properties. The first two publications included in the thesis describe two different approaches to address permittivity measurements. The first paper describes a versatile, stand-alone, and easy-to-use instrument for measuring the permittivity materials inside tubes. The design of the cavity achieved an excellent sensitivity, and the study of the coupling network allowed the characterization of low, moderate, and high-loss materials with the same setup. This device included an in-house portable vector reflectometer, making it portable and cost-affordable. The features of the developed instrument allow straightforward use by non-specialized personnel and provide versatility in many situations. The second publication presents a specific open-ended coaxial design with increased sensitivity to determine the permittivity of lossy food products as a function of temperature at RF frequencies. This paper highlight the relevance of selecting the most suitable measurement technique, adapted to the environment and particularities of the material, for the appropriate determination of permittivity. The following two papers describe the development and use of a near-field scanning microwave microscope with micrometric resolution to determine permittivity maps of heterogeneous planar materials at microwave frequencies. The different elements comprising the microscope instrument and the analysis techniques to determine permittivity values from the resonance measurements were described throughout both works. In the first paper, microwave technology was employed for the first time in anti-counterfeiting applications by obtaining the dielectric mark of a banknote watermark. Besides, this study showed the ability of microwave energy to detect hidden marks behind dielectric or metallic layers, opening new possibilities for developing optically opaque security features untraceable by optical means. The second study demonstrates the versatility of this system in determining the dielectric properties of heterogeneous planar materials by measuring the dielectric response of rock specimens. The methods developed in this thesis dissertation increase the portfolio of dielectric characterization systems and can help a wide range of scientific and industrial sectors in dielectric monitoring and characterization tasks, making these works more convenient and accessible.Financial support through the grant reference BES-2016-077296 of the call Convocatoria de las ayudas para contratos predoctorales para la formación de doctores de 2016 by Ministerio de Economía y Competitividad (MINECO) and by European Social Funds (ESF) of European Union is also gratefully acknowledgedGutiérrez Cano, JD. (2022). Microwave Dielectrometry Adapted to Environments [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/186351TESISCompendi

Temperature- and Time-Dependent Dielectric Measurements and Modelling on Curing of Polymer Composites

In this book a test set for dielectric measurements at 2.45 GHz during curing of polymer composites is developed. Fast reconstruction is solved using a neural network algorithm. Modeling of the curing process at 2.45 GHz using both dielectric constant and dielectric loss factor results in more accurate model compared to low frequency modelling that only uses the loss factor. Effect of various hardeners and different amount of filler is investigated

Temperature- and Time-Dependent Dielectric Measurements and Modelling on Curing of Polymer Composites

In this book a test set for dielectric measurements at 2.45 GHz during curing of polymer composites is developed. Fast reconstruction is solved using a neural network algorithm. Modeling of the curing process at 2.45 GHz using both dielectric constant and dielectric loss factor results in more accurate model compared to low frequency modelling that only uses the loss factor. Effect of various hardeners and different amount of filler is investigated

Theory of passive remote sensing with microwaves

Theoretical models are described which were developed for use in the interpretation of microwave data from the earth's surface

Surface wave manipulation with polar dielectric thin films and topological photonic system

Different from the well-studied wave propagation in the bulk where a plane wave extending to infinite is often conceived, the surface wave exists in the boundary defined by domains of distinct medium is well-confined with exponentially decaying tails away from this interface. This tightly-localized nature grants us enormous capability to manipulate the wave transport by tailoring the property of the interfaces and further enables various functionality for practical application. In this dissertation, a charged particle accelerator based on the surface phonon polaritons on the polar dielectric (silicon carbide) thin film is demonstrated to withstand high energy laser power and holds the promise of ultra-high accelerating gradiant in future experimental realization. The framework of wave propagation is then expanded beyond the homogenized medium to crystals with discrete periodicity which is referred as photonic crystals. The Bloch wave construct predicts that the topological insulator, a novel phenomenon in solid state physics, can be emulated by exquisite design of photonic system. Consequently, the surface waves (or edge states) between two topologically distinct photonic crystals exhibit robust and defect-immune wave transport which facilitates wide variety of applications. In particular, the RF delay line, polarized wave sorting, and two-beam accelerator based on the photonic topological insulator are investigated.Physic

Electromagnetic Waves

This book is dedicated to various aspects of electromagnetic wave theory and its applications in science and technology. The covered topics include the fundamental physics of electromagnetic waves, theory of electromagnetic wave propagation and scattering, methods of computational analysis, material characterization, electromagnetic properties of plasma, analysis and applications of periodic structures and waveguide components, and finally, the biological effects and medical applications of electromagnetic fields

Encapsulamento de nanopartículas à base de óxido de ferro com sílica para aplicações biomédicas

Over last decades, a great attention has been devoted to iron oxide-based nanoparticles coated by dielectric organic or inorganic materials for the potential contributions in biomedical applications and microwave absorbers industry. The present Ph.D. study focuses on the fabrication of iron-based oxide nanoparticles and coating the particles within the silica matrix in the form of a core-shell structure exhibiting interesting magnetic and electrical properties for application in the biomedical and microwave technology areas. The combined study of electrical and magnetic properties of the silica-iron oxide composites allowed us to examine the requisites for application in a new generation of the high-efficient microwave absorbents and also for the possibility of hyperthermia and drug delivery agents. In this context, four synthesis methods: sol-gel route, laser floating zone (LFZ), auto-combustion, and Pechini method were employed to prepare the iron oxide-based/silica composites. Several studies, namely, structural, morphological, electrical and magnetic characterizations, were performed on the prepared samples. The utilization of several experimental characterizing techniques not only provide us a comprehensive knowledge of the physical properties of these materials but also look over the future employment of the prepared composites in the biomedical application and the microwave absorbing materials. It was prepared a series of glasses with the composition, xFe2O3-(100-x)SiO2 (x=1, 2, 10, 20 in mol%) by the sol-gel route. The effect of the heat treatment conditions and the Fe/Si ratio on the morphology, electrical and magnetic properties of the glass ceramics were investigated. Fibers with the composition of 10Fe2O3-90SiO2 were processed by LFZ technique. Their morphology, structure, magnetic properties and redox state were studied in function of the pulling rate. An exhautive study on the Raman spectroscopy and the local magnetic microstructure of the fibers were performed to support for a deeper understanding of the magnetic properties of the fibers. A series of manganese ferrite-silica nanocomposites with the composition xMnFe2O4-(100-x)SiO2 (x=100, 20, 15 and 10 in mol%) were prepared by the auto combustion method. The physical parameters obtained from this study showed the great potential of the silica-manganese ferrite nanocomposites for the proposed applications as well other suggested future works. In addition, a preliminary study on the synthesis by the Pechini method and characterization of iron oxide was carried out. The structure, the magnetic properties and the electric conduction mechanism of the prepared iron oxide polycrystallites were investigated leaving open other possible applications industries.Nas últimas décadas grande atenção tem sido dedicada ao estudo de nanopartículas à base de óxido de ferro revestidas por materiais dielétricos orgânicos ou inorgânicos com potencial para aplicações biomédicas e na indústria de absorventes de microondas. O presente trabalho de doutoramento centra-se na fabricação de nanopartículas de óxido de ferro e no seu revestimento com sílica na forma de uma estrutura núcleo-casca com o objectivo de obter propriedades magnéticas e elétricas interessantes para aplicações práticas na área biomédica e na indústria de microondas. O estudo combinado das propriedades elétricas e magnéticas dos compósitos de óxido de ferro-sílica permitiu estudar as características para aplicações em nova geração de absorventes de micro-ondas de alta eficiência e também agentes com possíveis utilizações em hipertermia e libertação de drogas. Neste contexto foram utilizados, quatro métodos de síntese: método de sol-gel, técnica fusão de zona flutuante com laser (LFZ), autocombustão e método de Pechini na preparação dos compósitos à base de óxido de ferro / sílica. Vários estudos como caracterização estrutural, morfológica, elétrica e magnética, foram realizados nas amostras preparadas. A utilização de várias técnicas de caracterização experimental fornece um conhecimento abrangente das propriedades físicas destes materiais e permite perspectivar o possível emprego destes compósitos para aplicações biomédicas e como materiais absorventes de micro-ondas no futuro. Foi preparada a série de vidros xFe2O3- (100-x) SiO2 (x = 1, 2, 10, 20 em mol%) pelo método de rota sol-gel. O efeito das condições de tratamento térmico e da relação Fe / Si na morfologia, propriedades elétricas e magnéticas das cerâmicas vítreas foi investigado. Fibras com a composição 10Fe2O3-90SiO2 foram processadas pela técnica de LFZ. A sua morfologia, estrutura, propriedades magnéticas e estado de redução foram estudadas em função da taxa de extração da preparação das amostras. Foi realizada uma análise exaustiva dos resultados da espectroscopia de Raman e uma pesquisa da microestrutura magnética local para melhor interpretar as características magnéticas das fibras. Uma série de nanocompósitos de silício-ferrite de manganês com a composição xMnFe2O4- (100-x) SiO2 (x = 100, 20, 15 e 10 em % molar) foi preparada pelo método de auto-combustão. Foi realizada investigação das propriedades estruturais, morfológicas, elétricas e magnéticas destas amostras. Os parâmetros físicos obtidos a partir desse estudo mostraram o grande potencial dos nanocompósitos de silício-ferrita de manganês para as aplicações propostas assim como para o trabalho futuro sugerido. Além disso, também foi realizado um estudo preliminar sobre a síntese e caracterização do óxido de ferro pelo método de Pechini.A estrutura, as propriedades magnéticas, o mecanismo de condução elétrica das policristalitas de óxido de ferro preparados foram realizadas deixando em aberto outras possíveis aplicações industriais.Programa Doutoral em Engenharia Físic

Temperature- and Time-Dependent Dielectric Measurements and Modelling on Curing of Polymer Composites

In this work a test set for dielectric measurements at 2.45 GHz during curing of polymer composites is developed. Fast reconstruction of dielectric properties is solved using a neural network algorithm. Modelling of the curing process at 2.45 GHz using both dielectric constant and dielectric loss factor results in a more accurate model compared to low frequency modeling that only uses the loss factor. Effects of various harderners and different amount of filler are investigated