Electrowetting: from basics to applications

Electrowetting has become one of the most widely used tools for manipulating tiny amounts of liquids on surfaces. Applications range from 'lab-on-a-chip' devices to adjustable lenses and new kinds of electronic displays. In the present article, we review the recent progress in this rapidly growing field including both fundamental and applied aspects. We compare the various approaches used to derive the basic electrowetting equation, which has been shown to be very reliable as long as the applied voltage is not too high. We discuss in detail the origin of the electrostatic forces that induce both contact angle reduction and the motion of entire droplets. We examine the limitations of the electrowetting equation and present a variety of recent extensions to the theory that account for distortions of the liquid surface due to local electric fields, for the finite penetration depth of electric fields into the liquid, as well as for finite conductivity effects in the presence of AC voltage. The most prominent failure of the electrowetting equation, namely the saturation of the contact angle at high voltage, is discussed in a separate section. Recent work in this direction indicates that a variety of distinct physical effects¿rather than a unique one¿are responsible for the saturation phenomenon, depending on experimental details. In the presence of suitable electrode patterns or topographic structures on the substrate surface, variations of the contact angle can give rise not only to continuous changes of the droplet shape, but also to discontinuous morphological transitions between distinct liquid morphologies. The dynamics of electrowetting are discussed briefly. Finally, we give an overview of recent work aimed at commercial applications, in particular in the fields of adjustable lenses, display technology, fibre optics, and biotechnology-related microfluidic devices

Nanocomposite electrical insulation: multiscale characterization and local phenomena comprehension

Dans le domaine de l'isolation électrique, il a été démontré que les matériaux hybrides organiques/inorganiques nanocomposites (NC) assurent une nette amélioration de leur fonctionnement à haute température/haute tension et permettent aux systèmes d'isolation électrique de renforcer leurs propriétés diélectriques. Récemment, il a été démontré que certaines modifications des propriétés électriques telles que la permittivité, la rupture diélectrique, la résistance aux décharges partielles ou la durée de vie étaient souvent attribuées à l'interphase nanoparticule/matrice, une région où la présence des nanoparticules modifie les propriétés de la matrice. De plus, des études récentes montrent qu'une fonctionnalisation de la surface des nanoparticules permet une meilleure dispersion dans la matrice hôte. Cette meilleure dispersion affecte la zone d'interphase et joue également un rôle majeur dans l'amélioration des propriétés des nanocomposites. Cependant, le rôle de l'interphase reste théorique et peu de résultats expérimentaux existent pour décrire ce phénomène. Par conséquent, en raison de l'échelle nanométrique de l'interphase, une caractérisation de ses propriétés demeure un défi. Au cours de cette thèse, deux études principales sont menées afin de mieux comprendre la relation structure-propriété dans les polymères nanocomposites. Tout d'abord, la microscopie à force atomique (AFM) est utilisée pour effectuer simultanément des mesures qualitatives et quantitatives de ces zones d'interaction dans le nanocomposite polyimide/nitrure de silicium (PI/Si3N4). Le mode Peak Force Quantitative Nano Mechanical (PF QNM) dérivé de l'AFM révèle la présence de l'interphase en mesurant les propriétés mécaniques (module de Young, déformation ou adhérence). Le mode microscopie à force électrostatique (EFM) est utilisé pour détecter et mesurer la permittivité locale de la matrice et de l'interphases. Par ailleurs, l'objectif de ce travail est de présenter l'effet de la fonctionnalisation de surface des nanoparticules de nitrure de silicium (Si3N4) sur les régions d'interphase. Ces résultats quantitatifs, à la fois mécaniques et électriques, permettent de comparer la dimension et les propriétés des interphase autour des nanoparticules traitées et non traitées. Par conséquent, cette nouvelle approche de caractérisation de cette zone confronte les résultats expérimentaux à des modèles théoriques. Un nouveau modèle basé sur les résultats expérimentaux obtenus est proposé. De plus, la deuxième partie de cette étude présente une caractérisation macroscopique des propriétés et de la rigidité diélectrique des films de polyimide pur, du nanocomposite avec des particules traitées et non traités. Les résultats révèlent le rôle de l'interphase sur la réduction du phénomène de polarisation de l'électrode (PE) dû aux mouvements ioniques surtout à haute température. Pour les nanoparticules non traitées, ces effets sont moins importants en raison de la formation d'agrégats. En revanche, une diminution nette de la PE est obtenue en fonctionnalisant la surface des nanoparticules avec le silane comme agent de couplage. Enfin, la rigidité diélectrique de l'ensemble des échantillons est mesurée et montre une augmentation considérable de la performance diélectrique des nanocomposites à haute température par rapport au PI pur.In the electrical insulation field, it was demonstrated that nanocomposite (NC) organic/inorganic hybrid materials assure a distinct improvement of their high temperature/high voltage functioning and allow the electrical insulation to strengthen its dielectric properties. Recently, it was shown that some modifications of the electrical properties such as permittivity, dielectric breakdown, partial discharges resistance or lifetime are often awarded to the nanoparticle/matrix interphase, a region where the presence of the nanoparticle changes the matrix properties. Moreover, recent studies show that the nanoparticle surface functionalization allows a better dispersion of the particles within the host matrix. This better dispersion affects the interphase zone and plays a major role in the nanocomposite properties improvement as well. However, the role of the interphase remains theoretical and few experimental results exist to describe this phenomenon. Accordingly, because of its nanometer scale, the interphase properties characterization remains a challenge. Two main studies are carried out, during this thesis work, that can provide a better understanding of structure-properties relationships in polymer nanocomposite. First, Atomic Force Microscopy (AFM) is employed to make at the same time qualitative and quantitative measurements of these interaction zones within Polyimide/Silicon Nitride (PI/Si3N4) nanocomposite. The Peak Force Quantitative Nano Mechanical (PF QNM) AFM mode reveals the presence of the interphase by measuring mechanical properties (Young modulus, deformation or adhesion). Electrostatic force microscope (EFM) mode is used in order to detect and measure the matrix and interphase local permittivity. Moreover, the aim of this work is to present the effect of the surface functionalization of silicon nitride (Si3N4) nanoparticles on the interphase regions. Mechanical and electrical quantitative results permit comparing the interphase dimension and properties between treated and untreated Si3N4 nanoparticles. As a result, this new approach to characterize the nanocomposite interphase zone using local measurements confronts experimental results with theoretical models. A new model based on the obtained experimental results is proposed. In addition, the second part of this study presents a macroscopic investigation on the dielectric properties and breakdown strength of neat polyimide, untreated and treated nanocomposite films. Results reveal the interphase role on the reduction of the electrode polarization (EP) phenomenon due to ionic movements especially at high temperatures. For untreated nanoparticles, these effects are less important due to the aggregate formation. In contrast, an EP drastic decrease is obtained by functionalizing the nanofiller surface with a silane coupling agent. Finally, the high temperature breakdown strength for all samples is investigated and shows a considerable increase of nanocomposites dielectric performance at high temperature compared to neat PI

Studies of core-shell nanoGUMBOS and liposomal ionogels

The work presented in this dissertation is a description of novel core-shell nanomaterials derived from a group of uniform materials based on organic salts (GUMBOS) and the synthesis and characterizations of novel liposomal ionogels (LIGs). These GUMBOS are an extension of ionic liquids (ILs) which are organic salts with melting points between 25 °C and 100 °C. Ionic liquids have high thermal stability, low vapor pressure, and tunable physiochemical and functional properties. All of the properties of ILs are controlled by the chosen cation and anion pair. Similarly to ILs, GUMBOS possess the same qualities; however, they have melting points up to 250 °C. The first section is a discussion of core-shell nanomaterials composed of GUMBOS and gold. Chapter 3 is a description of the synthesis of thiol-functionalized GUMBOS and their corresponding nanoparticles (nanoGUMBOS). NanoGUMBOS were prepared using non-templated and templated methods. Non-templated nanoparticles were obtained through ionic self-assembly using a reprecipiation procedure. A reverse micellar method was utilized in the preparation of templated nanoGUMBOS. NanoGUMBOS were used as core components for the core-gold shell nanoparticles. The optical and morphological properties of nanoGUMBOS were monitored throughout the gold-coating process. Although gold-coated nanoGUMBOS have potential uses in biomedical applications, they were investigated as organic solvent sensors. In chapter 4, 1D core-shell nanoGUMBOS were prepared using a porous anodic alumina template. The corresponding optical and morphological characteristics of the nanorods were also determined along with the gold-coating procedure. With interest in electrochemical applications, cyclic voltammetry measurements were performed to determine the electronic properties of bulk GUMBOS. The second section is a description of a new type of ionogel that utilizes liposomes as the gelation matrix which we have named liposomal ionogels (LIGs). The ionogels developed in this dissertation are composed of a biocompatible IL which is prepared from choline and the amino acid proline along with dipalmitoylphosphatidylcholine (DPPC) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) phospholipids. These LIGs offer two tunable components, phospholipids and ILs, and have potential as topical drug delivery tools

Nanoscale GUMBOS: Size-Control, Characterization, and Applications as Enantioselective Molecularly Imprinted Polymers and Fluorescent Materials

Nanomaterials derived from a group of uniform materials based on organic salts (GUMBOS) have been introduced into the scientific literature through many analytical, biological, and technological applications. These nanomaterials, referred to as nanoGUMBOS, have been shown to display a number of interesting properties including fluorescence, magnetism, tumor targeting, and optoelectronic properties. Herein, we present major studies on nanoGUMBOS including synthesis and size-control, chiral molecular imprinting in polymers, as well as investigation of optical properties and quantum yield of fluorescent semiconductor-based nanoGUMBOS. Various strategies were introduced for production of well-defined nanoGUMBOS. Specifically, several methods based on sonochemistry, microwave, cyclodextrin, and surfactant-assisted syntheses of nanoGUMBOS are described while evaluating the efficiency of each technique in controlling size, morphology, and uniformity of nanoparticles. The systematic variations in experimental parameters such as concentration, cation-to-anion ratio, as well as presence and type of templates introduced for the formation of nanoGUMBOS were also investigated. Moreover, imidazolium-based ionic liquid crosslinkers were tested as platforms for chiral imprinting under aqueous conditions. Using photoinitiated dispersion polymerization, molecularly imprinted polymeric nanoGUMBOS were designed with recognition properties for L-tryptophan. Rebinding studies were performed in batch mode analysis using fluorescence spectroscopy. Strong interactions between GUMBOS and L-tryptophan made imprinting possible in aqueous media. Various spacers between the imidazolium rings of the cation afforded the presence of secondary interactions responsible for distinctive enantiorecognition behavior of these polymeric nanoparticles. In this regard, these vinylimidazolium ionic liquids were polymerized using gamma irradiation, for potential application in drug loading. Furthermore, carbazole-based nanoGUMBOS were investigated as fluorescent materials for potential applications in blue organic light emitting devices. These nanoGUMBOS were synthesized using a reprecipitation method in the absence or presence of 2-hydroxypropyl-â-cyclodextrin, in order to tune the size and optical properties of the nanoparticles. The carbazoleimidazole-based cation was coupled with different couteranions: iodide ([I]), trifluoromethanesulfonate ([OTf]), and bis(pentafluoroethylsulfonyl)imide ([BETI]). Absolute quantum yields were compared for each type of nanoGUMBOS synthesized under different experimental conditions. Doping with the transition metal Cu2+ was also explored as an alternative strategy for tuning the quantum yield of nanoGUMBOS, which was enhanced by optimizing the molar percentage of dopant to host

Estudio experimental, analítico y numérico del fallo mecánico del aislamiento celulósico de conductores continuamente transpuestos en transformadores de potencia bajo la influencia de cortocircuitos y envejecimiento térmico

RESUMEN: El papel dieléctrico de un transformador de potencia está sometido a un proceso de envejecimiento, producido por altas temperaturas y reacciones químicas en el aceite dieléctrico. Las fuerzas electromagnéticas que afectan a los conductores pueden producir la rotura del papel, llegando a causar el fin de la vida útil del transformador. Para mejorar la comprensión de estos fenómenos, un conductor continuamente transpuesto (CTC) con cuatro capas de dieléctrico (papel Kraft ordinario y tipo crepe) fue impregnado en aceite nafténico y envejecido durante diferentes periodos, representando toda su vida útil. Muestras del CTC fueron sometidas a deformaciones de flexión compatibles con un cortocircuito, analizándose las grietas generadas en el papel. El papel dieléctrico envejecido fue caracterizado mecánicamente (a tracción, compresión y tangencialmente), y el ensayo a flexión se simuló numéricamente en ANSYS Static Structural, para estimar las deformaciones en el papel. Dos criterios analíticos de fallo (máxima deformación y criterio de Norris) fueron adaptados para predecir las regiones del papel dieléctrico susceptibles de fallar para un estado de envejecimiento y deformación impuesta determinados, obteniendo predicciones coherentes con los resultados experimentales y validando así el enfoque de Norris.ABSTRACT: The dielectric paper of power transformers is subjected to ageing caused by high temperatures and chemical reactions in the dielectric oil. The electromagnetic forces the conductor is subjected to can cause the breakage of the paper and even the end of the useful life of the transformer. To improve the understanding of those phenomena, a continuously transposed conductor (CTC) with four layers of dielectric paper (plain Kraft and crepe papers) was impregnated in naphthenic oil and aged during different periods, representative of its whole lifespan. CTC samples were subjected to bending deformations compatible with a short circuit, and the cracks generated in the paper were analysed. The aged paper was mechanically characterised (in tensile, compressive and shear modes) and the bending tests were simulated in ANSYS Static Structural, to estimate the strains in the paper. Two analytical failure models (maximum strain and Norris criterion) were modified to predict the regions in the dielectric paper susceptible to fail for a particular ageing state and deformation level, obtaining a good agreement with the experimental results and thus validating the Norris approach

Enhanced fluid characterization in the millimeter-wave band using Gap Waveguide Technology

[EN] Microfluidic systems have been emerged as a promising technology for molecular analysis, biodefence and microelectronics. The properties of the microfluidic devices, such as rapid sample processing and the precise control of fluids, have made them attractive candidates to replace traditional experimental approaches. Microfluidic devices are characterized by fluidic channels with dimensions on the order of tens to hundreds of micrometers. Structures with this size enable the integration of lab-on-chip technology, which allows processing miniaturized devices for fluid control and manipulation. Fluid sensing by microwave sensors based on the RF analysis offers new possibilities for the characterization of mediums by non-invasive methods. Dielectric measurement of fluids is important because it can provide the electric or magnetic characteristics of the materials, which proved useful in many research and development fields, such as molecular biology and medical diagnosis. Several techniques are available in the frequency domain for analyzing the dielectric properties of liquids and their composition. We are focused in resonant cavity techniques for fluid characterization in the millimeter-wave range. However, these techniques are incompatible with lab-on-chip process due its dimensions in this frequency range. In this context, a new structure called gap waveguide appears as a good candidate to overcome the principal drawbacks of the classical resonant cavities. This thesis presents the development of the gap waveguide technology in the millimeter-wave band. Other conventional technologies are discussed as well, to compare them with the performance in terms of losses of the gap waveguide. We also present the resonator design based on gap waveguide with the purpose of making the gap waveguide a technology capable of working in the microfluidic sensing domain. In this context, we propose a comparative study between gap waveguide and Substrate Integrated Cavity (SIC) with the aim to characterize the fluid permittivity at 60 GHz. With this purpose, several prototypes have been manufactured with PCB ("Printed Circuit Board") and Low Temperature Co-fired Ceramic (LTCC) technologies. A work in the LTCC laboratory has been done with the purpose of validating some steps in the LTCC process which are key in the gap waveguide manufacturing, especially those related with the creation of cavities (external and internal) using LTCC materials.[ES] Los sistemas microfluídicos han emergido como una tecnología prometedora para el análisis molecular, biodefensa y microelectrónica. Las propiedades de los dispositivos microfluídicos tales como el procesamiento rápido de las muestras y el control de los fluidos, les han hecho atractivos candidatos para reemplazar los tradicionales métodos experimentales. Los dispositivos microfluídcos están caracterizados por canales fluídicos con dimensiones del orden de decenas a centenares de micrómetros. Las estructuras con estos tamaños permiten la integración de la tecnología "lab-on-chip", la cual permite el procesamiento de dispositivos miniaturizados para el control y la manipulación de fluidos. La detección de fluidos a través de sensores de microondas basados en el análisis de radiofrecuencia ofrece nuevas posibilidades para la caracterización de medios a través de métodos no invasivos. Las medidas dieléctricas de los fluidos son importantes debido a que pueden proporcionar información las características eléctricas o magnéticas de los materiales, siendo útil en muchos campos de investigación y desarrollo tales como biología molecular o para realizar diagnósticos médicos. En el dominio frecuencial, varias tecnologías están disponibles en el mercado para analizar las propiedades dieléctricas y la composición de los líquidos. En esta tesis, estamos enfocados en las técnicas basadas en cavidades resonantes para la caracterización de fluidos en el rango de las ondas milimétricas. Sin embargo, estas técnicas son incompatibles con los procesos "lab-on-chip" debido a sus dimensiones en esta banda de frecuencia. En este contexto, una nueva estructura guía onda denominada "gap waveguide" aparece como un buen candidato para solventar los principales inconvenientes de las clásicas cavidades resonantes. En esta tesis se ha desarrollado la tecnología "gap waveguide" en la banda de ondas milimétricas. Otras tecnologías convencionales serán estudiadas para comparar el rendimiento de todas ellas en términos de pérdidas. También se presenta en esta tesis, el diseño de resonadores basados en la tecnología "gap waveguide" con el propósito de hacer esta tecnología compatible con la detección microfluídica. En este contexto, proponemos un estudio comparativo entre las tecnologías "gap waveguide" y "Substrate Integrated Cavity" (SIC) con el objetivo de caracterizar la permitividad de los fluidos a 60 GHz. Con este propósito, varios prototipos han sido fabricados usando las tecnologías PCB ("Printed Circuit Board") y LTCC ("Low Temperature Co-fired Ceramic". Un importante trabajo en el laboratorio LTCC se realizó para validar algunas de las etapas del proceso LTCC que eran la clave para la fabricación de prototipos basados en "gap waveguide", como la creación de cavidades (externas e internas) usando materiales LTCC.[CA] Els sistemes microfluídics han emergit com una tecnologia prometedora per a l'anàlisi molecular, biodefensa i microelectrònica. Les propietats dels dispositius microfluídics com el processament ràpid de les mostres i control dels fluids, els han fet atractius candidats per a reemplaçar les tradicionals aproximacions experimentals. Els dispositius microfluídcs estan caracteritzats per canals fluídics amb dimensions de l'orde de desenes a centenars de micròmetres. Les estructures amb estes grandàries permeten la integració de la tecnologia "lab-on-chip", la qual permet el processament de dispositius miniaturitzats per al control i la manipulació de fluids. La detecció de fluids a través de sensors de microones basats en l'anàlisi de radiofreqüència oferix noves possibilitats per a la caracterització de sistemes a través de mètodes no invasius. Les mesures dielèctriques dels fluids són importants pel fet que poden proporcionar informació sobre les característiques elèctriques o magnètiques dels materials, sent útil en molts camps d'investigació i desenvolupament com biologia molecular o per a realitzar diagnòstics. En el domini freqüencial, diverses tecnologies estan disponibles en el mercat per analitzar les propietats dielèctriques i la composició dels líquids. En aquesta tesi, estem enfocats en les tècniques basades en cavitats ressonants per a la caracterització de fluids en el rang de les ones mil·limètriques. No obstant això, aquestes tècniques són incompatibles amb els processos "lab-on-chip" a causa de les seues dimensions en aquesta banda de freqüència. En aquest context, una nova estructura guia onda denominada "gap waveguide" apareix com un bon candidat per a resoldre els principals inconvenients de les clàssiques cavitats ressonants. En aquesta tesi s'ha desenvolupat la tecnologia "gap waveguide" en la banda d'ones mil·limètriques. Altres tecnologies convencionals seran estudiades per a comparar el rendiment de totes elles en termes de pèrdues.També es presenta en esta tesi el disseny de ressonadors basats en la tecnologia "gap waveguide" amb el propòsit de fer esta tecnologia compatible amb la detecció microfluídica. En aquest context, proposem un estudi comparatiu entre les tecnologies "gap waveguide" i "Substrate Integrated Cavity" (SIC) amb l'objectiu de caracteritzar la permitivitat dels fluids a 60 GHz. Amb aquest propòsit, diversos prototips han sigut fabricats usant les tecnologies PCB ("Printed Circuit Board") i LTCC ("Low Temperature Co-fired Ceramic". Un important treball en el laboratori LTCC es va realitzar per a validar algunes de les etapes del procés LTCC que eren la clau per a la fabricació de prototips basats en "gap waveguide", com la creació de cavitats (externes i internes) usant materials LTCC.Arenas Buendia, C. (2016). Enhanced fluid characterization in the millimeter-wave band using Gap Waveguide Technology [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/62781TESI

Characterisation of sedimentary structure and hydraulic behaviour within the unsaturated zone of the Triassic Sherwood Sandstone aquifer in North East England

A study of the sedimentological framework and permeability characteristics of the Sherwood Sandstone has been undertaken together with a detailed investigation of moisture migration in the vadose zone at a single field site. Sedimentary structure and likely permeability variations were studied by use of laboratory grainsize analysis, logging of nearby outcrops, borehole geophysics and Ground Penetrating Radar (GPR). GPR is ideal for vadose zone hydrogeological applications as the majority of the features imaged are visible to radar as a result of variations in capillary, held moisture, and the amount of capillary retention is controlled by the size of the pore throats in the sediments, which directly influences their permeability properties. Combined use of GPR, reconstruction of sedimentary facies and quantification of permeability characteristics has provided detailed 3D models of the sedimentary subsurface. Time Domain Reflectometry (TDR) was used to monitor water movement within the Sherwood Sandstone at a site near Selby in Yorkshire, creating a vertical and lateral profile of groundwater movement within the unsaturated zone. Moisture content has also been monitored using a neutron probe, and a commercially-available portable packer system, which have provided verification of the accuracy of the custom-made TDR system. The TDR installations consisted of automated arrays of TDR probes, permanently installed upon borehole packers at varying depths, and these have provided moisture content data of a high temporal resolution. The TDR system has allowed monitoring of seasonal moisture variation under natural rainfall loading, and the results have been interpreted in order to gain a better understanding of groundwater migration at a different scale to data previously available. The bulk of the rock in the Sherwood Sandstone aquifer study area consists of relatively permeable medium-grained sandstones. However, results suggest that vertical flow in the unsaturated zone may be impeded by the presence of relatively impermeable fine sandstone units, which correspond to bar top and slack water environments, and occasional mudstone layers representing overbank deposits. This restriction to vertical flow may cause localized perched aquifer conditions, which provide sufficient hydrostatic head to initiate horizontal migration in the overlying rock. Modelling of real rainfall events suggests that 25% of the water present in the perched aquifer layers undergoes lateral or bypass flow (i. e. it drains laterally rather than through the fine-grained layers). In the saturated zone, the horizontal flow of groundwater in the Sherwood Sandstone aquifer is likely to be dominantly via the relatively coarse, trough-stratifed sandstone layers, so that a low proportion of the total aquifer porosity may provide a route for rapid contaminant transport

Non-Invasive Blood Glucose Monitoring Using Electromagnetic Sensors

Monitoring glycemia levels in people with diabetes has developed rapidly over the last decade. A broad range of easy-to-use systems of reliable accuracies are now deployed in the market following the introduction of the invasive self-monitoring blood glucose meters (i.e., Glucometers) that utilize the capillary blood samples from the fingertips of diabetic patients. Besides, semi-invasive continuous monitors (CGM) are currently being used to quantify the glucose analyte in interstitial fluids (ISF) using an implantable needle-like electrochemical sensors. However, the limitations and discomforts associated with these finger-pricking and implantable point-of-care devices have established a new demand for complete non-invasive pain-free and low-cost blood glucose monitors to allow for more frequent and convenient glucose checks and thereby contribute more generously to diabetes care and prevention. Towards that goal, researchers have been developing alternative techniques that are more convenient, affordable, pain-free, and can be used for continuous non-invasive blood glucose monitoring. In this research, a variety of electromagnetic sensing techniques were developed for reliably monitoring the blood glucose levels of clinical relevance to diabetes using the non-ionizing electromagnetic radiations of no hazards when penetrating the body. The sensing structures and devices introduced in this study were designed to operate in specific frequency spectrums that promise a reliable and sensitive glucose detection from centimeter- to millimeter-wave bands. Particularly, three different technologies were proposed and investigated at the Centre for Intelligent Antenna and Radio Systems (CIARS): Complementary Split-Ring Resonators (CSRRs), Whispering Gallery Modes (WGMs) sensors, and Frequency-Modulated Continuous-Wave (FMCW) millimeter-Wave Radars. Multiple sensing devices were developed using those proposed technologies in the micro/millimeter-wave spectrums of interest. A comprehensive study was conducted for the functionality, sensitivity, and repeatability analysis of each sensing device. Particularly, the sensors were thoroughly designed, optimized, fabricated, and practically tested in the laboratory with the desired glucose sensitivity performance. Different topologies and configurations of the proposed sensors were studied and compared in sensitivity using experimental and numerical analysis tools. Besides, machine learning and signal processing tools were intelligently applied to analyze the frequency responses of the sensors and reliably identify different glucose levels. The developed glucose sensors were coupled with frequency-compatible radar boards to realize small mobile glucose sensing systems of reduced cost. The proposed sensors, beside their impressive detection capability of the diabetes-spectrum glucose concentrations, are endowed with favourable advantages of simple fabrication, low-power consumption, miniaturized compact sizing, non-ionizing radiation, and minimum health risk or impact for human beings. Such attractive features promote the proposed sensors as possible candidates for development as mobile, portable/wearable gadgets for affordable non-invasive blood glucose monitoring for diabetes. The introduced sensing structures could also be employed for other vital sensing applications such as liquid type/quantity identification, oil adulteration detection, milk quality control, and virus/bacteria detection. Another focus of this thesis is to investigate the electromagnetic behavior of the glucose in blood mimicking tissues across the microwave spectrum from 200 MHz to 67 GHz using a commercial characterization system (DAK-TL) developed by SPEAG. This is beneficial to locate the promising frequency spectrums that are most responsive to slight variations in glucose concentrations, and to identify the amount of change in the dielectric properties due to different concentrations of interest. Besides, the effect of the blood typing and medication was also investigated by measuring the dielectric properties of synthetic “artificial” as well as authentic “human” blood samples of different ABO-Rh types and with different medications. Measured results have posed for other factors that may impact the developed microwave sensors accuracy and sensitivity including the patient’s blood type, pre-existing medical conditions, or other illnesses