Este trabalho de doutorado apresenta o desenvolvimento de novas tecnologias para fabricação de microsistemas analíticos e detecção eletroquímica. Primeiramente, a poliuretana elastomérica, derivada de uma fonte renovável, o óleo de mamona, foi utilizada como um novo e alternativo material para fabricação de microdispositivos. Foram avaliadas as características físicas dos microcanais formados por moldagem, a compatibilidade química com solventes e eletrólitos, as características de superfície através dos ângulos de contato, o EOF em diferentes pHs e a performance analítica em experimentos de eletroforese com detecção eletroquímica. A segunda parte do trabalho apresenta o desenvolvimento de um método para a determinação simultânea de azo-corantes comumente usados na indústria alimentícia. Amaranto, amarelo crepúsculo FCF, amarelo sólido AB, ponceu 4R e vermelho 2G, foram separados e quantificados através de eletroforese em microdispositivos com detecção eletroquímica. Foram estudados e otimizados vários parâmetros que influenciaram a separação eletroforética e detecção eletroquímica, em experimentos realizados usando microdispositivos de vidro e eletrodo de trabalho de carbono vítreo. Finalmente, a terceira parte desse trabalho apresenta o uso das propriedades magnéticas e eletrocatalíticas de nanofios de níquel no desenvolvimento de um detector adaptativo magneticamente modulável para eletroforese em microdispositivos. / The development of microfluidic analytical systems has witnessed an explosive growth during the last 15 years. Particular attention has been given to microchip electrophoresis because of their fast and efficient separation capabilities. Electrochemistry detection offers considerable promise for such microfluidic systems, with features that include remarkable sensitivity, inherent miniaturization and portability, low cost, and high compatibility with microfabrication technologies. This thesis shows the development of new fabrication technologies for miniaturized analytical systems with electrochemical detection and it is presented in four chapters, Chapter I shows an introductory view of the main aspects related to miniaturization of analytical systems and amperometric detection configurations commonly coupled to microchip electrophoresis. In Chapter II, the use of elastomeric polyurethane (PU), derived from castor oil (CO) biosource, as a new material for fabrication of microfluidic devices by rapid prototyping is presented. Including the irreversible sealing step, PU microchips were fabricated in less than 1 h by casting PU resin directly on the positive high-relief molds fabricated by standard photolithography and nickel electrodeposition. Physical characterization of microchannels was performed by scanning electron microscopy (SEM) and profilometry. Polymer surface was characterized using contact angle measurements and the results showed that the hydrophilicity of the PU surface increases after oxygen plasma treatment. The polymer surface demonstrated the capability of generating an electroosmotic flow (EOF) of 2.6 × 10-4 cm2 V-1 s-1 at pH 7 in the cathode direction, which was characterized by current monitoring method at different pH values. The compatibility of PU with a wide range of solvents and electrolytes was tested by determining its degree of swelling over a 24 h period of contact. The performance of microfluidic systems fabricated using this new material was evaluated by fabricating miniaturized capillary electrophoresis systems. We used catecholamines as model analytes that were separated in aqueous solutions and detected with end-channel amperometric detection. In Chapter III, a method based on microchip electrophoresis with electrochemical detection has been developed for the simultaneous determination of Yellow AB, Red 2G, Sunset Yellow, Ponceu 4R, and Amaranth which are azo-dyes frequently added to foodstuffs. Factors affecting both separation and detection processes were examined and optimized, with best performance achieved by using a 10 mM phosphate buffer (pH 11) as running buffer and applying a voltage of 2500 V both in the separation and in the electrokinetic injection (duration 4 s). Under these optimal conditions, the target dye analytes could be separated and detected within 300 s by applying a detection potential of -1,0 V (vs. Ag/AgCl) to the glassy carbon (GC) working electrode. The recorded peaks were characterized by a good repeatability (RSD = 1,8 - 3,2%), high sensitivity, and a wide linear range. Detection limits of 3.8, 3.4, 3.6, 9.1, 15.1 ?M were obtained for Yellow AB, Red 2G, Sunset Yellow, Ponceu 4R, and Amaranth, respectively. Fast, sensitive, and selective response makes the new microchip protocol very attractive for the quantitative analysis of commercial soft drinks and candies Finally, in Chapter IV, we demonstrate for the first time the use of adaptive functional nickel nanowires for switching on demand operation of microfluidic devices. Controlled reversible magnetic positioning and orientation of these nanowires at the microchannel outlet offers modulation of the detection and separation processes, respectively. The former facilitates switching between active and passive detection states to allow the microchip to be periodically activated to perform a measurement and reset it to the passive (\"off\") state between measurements. Fine magnetic tuning of the separation process (post channel broadening of the analyte zone) is achieved by reversibly modulating the nanowire orientation (i.e., detector alignment) at the channel outlet. The concept can be extended to other microchip functions and stimuli-responsive materials and holds great promise for regulating the operation of microfluidic devices in reaction to specific needs or unforeseen scenarios.

L’analyse des gaz d’échappement des moteurs à combustion interne a été traditionnellement réalisée en laboratoires en utilisant des analyseurs de gaz en vrac avec des équipements coûteux. Afin de créer un système capable de réaliser le travail de ces analyseurs, un capteur pouvant détecter plusieurs gaz simultanément est indispensable pour en mesurer la concentration. En effet, utiliser un capteur pour chaque gaz est couteux et peut amener à des procédures complexes d’analyse en raison des différentes technologies utilisées. De plus, l’utilisation de multiples capteurs donne lieu à une perte de ressources financières et humaines. Pour pallier ce problème, une approche alternative proposée dans cette thèse consiste à utiliser un seul capteur pour l’analyse simultanée des différents gaz. Cette approche contribue à réduire la complexité des analyses, la taille et la collecte de données des mesures de gaz mentionnés précédemment. Elle permet également la baisse du coût de l’ensemble du système des mesures.Cette thèse présente la conception, la méthodologie et le développement d’une nouvelle approche pour la mesure de la concentration de gaz utilisant le traitement d’images numériques à travers la modélisation du mélange des couleurs d’émission de lumière dans le tube de décharge de gaz. L’application du modèle inverse permet d’obtenir le pourcentage de chaque gaz dans un mélange contenant jusqu'à quatre gaz connaissant la couleur d’émission du mélange et la couleur d’émission de chaque gaz. Nous discutons aussi le potentiel de certaines méthodes quant à leurs propriétés de miniaturisation et leurs limites. Une comparaison entre les différents capteurs miniaturisés est réalisée en termes suivant la sensibilité, la sélectivité, le coût et d’autres conditions. Pour atteindre les objectifs de recherche, les problèmes techniques rencontrés tels que la modélisation de mélange des couleurs, l’étalonnage de capteurs pour l’acquisition d’images, et le traitement des erreurs de mesures ont été identifiés et des solutions ont été proposées. / Gases represent one of the most important key measurands in many industrial and domestic activities. The need to detect single gas or a group of gases at the same time varies from one application to another. One of the most important applications of gas sensing is in the concentration measurement of exhaust emissions in internal combustion engines. The variety of gases emitted by these engines and the necessity for a precise measurement of their concentrations are the major incentives for researchers to develop gas sensors that are not only limited to a certain type of gases but to a variety of gases. The most interest gases include CO, NO, NO2, NH4, SO2, CO2, CH4 and other hydrocarbons. These gases can be harmful to human health if present beyond a certain concentration. The analysis of exhaust emissions of internal combustion engines has traditionally been achieved in laboratories using bulk gas analyzers and costly equipments. In order to create a system which can do the work of these analyzers, a sensor that can measure the concentration of multiple gases at the same time is needed. Instead of using a sensor for each gas which is costly and introduce another complexity to the analysis procedure due to the different technologies that are used in the detection of different types of gases. This directly translates into loss of financial and human resources that could otherwise be productively used. In an effort to remedy this situation, this dissertation proposes an alternate approach that uses one sensor to analyze multiple gases simultaneously. This has a significant potential in reducing the aforementioned complexity, size and data collection tasks, and at the same time can lower the cost of the overall system.This dissertation presents the design, methodology, and development of a new method for gas concentration measurement using digital image processing through modeling the color mixing of light emissions in gas discharge tube. The application of the inverse model allows us to get the percentages of each gas in a mixture of up to four gases knowing already the color of emission of the whole mixture and the color of emission of each gas alone. It also discusses the miniaturization potential of some of the methods that are promising in the ability of their miniaturization but suffer from different problems. A comparison is also done among the miniaturized sensors in terms of different parameters like sensitivity, selectivity, cost and other terms. In achieving the research objectives, major technical challenges such as color mixing modeling, imaging sensor calibration, and measurements’ error handling have been successfully identified and addressed.

De nombreux travaux de recherche sont actuellement menés afin de rendre les caméras infrarouges plus compactes et moins chères. En infrarouge refroidi, le défi est de proposer un système cryogénique compact pouvant être intégré sur un système à faible capacité d’emport tel qu’un drone. Dans ce cadre, l’utilisation d’une lentille mince en remplacement du filtre froid du cryostat permettrait de limiter la masse supplémentaire à refroidir et de maintenir constant le temps de descente en froid. En infrarouge non refroidi, l’objectif est de concevoir un petit capteur infrarouge bas coût « grand public » que l’on pourra inviter dans nos maisons, nos voitures, voire nos smartphones. L’utilisation d’une lentille mince ouvrirait la voie à des imageurs infrarouges peu onéreux.Dans ce contexte, j’ai choisi d’étudier le comportement d’une lentille de Fresnel dite d’ordre élevé intégrée dans une configuration optique de type landscape lens. J’ai montré que cette architecture optique mince peut fonctionner sur une large bande spectrale et sur un grand champ de vue. Cependant, les lentilles de Fresnel d’ordre élevé étant mal modélisées dans la littérature, j’ai développé mes propres algorithmes de modélisation afin de prévoir les performances d’un tel système. Grâce à cette étude, j’ai ensuite proposé deux systèmes d’imagerie, l’un refroidi et l’autre non refroidi. Chacun des deux systèmes a fait l’objet d’un prototype et a été entièrement caractérisé expérimentalement. Les résultats expérimentaux obtenus m’ont permis de valider les performances anticipées théoriquement et de mettre en évidence un phénomène de chromatisme diffractif latéral. Ces systèmes ouvrent la voie à deux nouvelles générations de caméras infrarouges. J’ai montré que l’imageur infrarouge refroidi possède une qualité image satisfaisante pour des applications d’aide au pilotage. Le prototype non refroidi est lui entièrement compatible avec des applications domotiques. Il a suscité l’intérêt de différents acteurs industriels. / Miniaturizing infrared optical systems is a research area of great interest nowadays in order to make them lighter and cheaper. In the cooled infrared domain, the objective is to design a compact cryogenic camera that could be integrated in a small-capacity carrier like a drone. To that purpose, replacing the cold filter of the dewar by a thin lens would limit the cooled down mass and would stabilize the cool down time. In the uncooled infrared domain, the objective is to design a small general use camera at a low cost. Its use could be generalized in houses, cars or even smartphones. The use of a thin lens would also pave the way for low-cost infrared imagers. In this context, I chose to study the imagery properties of a high order Fresnel lens integrated in a landscape lens architecture. I have demonstrated that this architecture can be used within a wide spectral range and over a wide field of view. However, current optical design software perform poorly on high order Fresnel lenses. Therefore, I have developed my own algorithms to model the performances of such a system. With that study, I have been able to design two prototypes with their own objectives: the first one is cooled and the second one is uncooled. Both systems have been demonstrated and entirely characterized. The experiment results have validated the theoretical performances of the systems and they highlighted an original kind of lateral chromatic aberration.These two systems pave the way to two new generations of infrared cameras. Indeed, on one hand I have proved that the cooled infrared quality may be good enough to qualify for an aircraft piloting aid. On the other hand, the uncooled prototype is fully compatible with low cost surveillance applications and the system raised the interest of various companies.

Radio frequency (RF) ion traps based on the quadrupole device developed by Paul and Steinwedel utilize a dynamic electric field to spatially confine the trajectory of charged particles and may be employed as mass spectrometers by selectively ejecting trapped molecules based on the mass to charge ratio. Because of the inherent sensitivity and specificity of this process, ion trap mass spectrometers have become a popular scientific instrument. In the past two decades there has been a push to develop portable ion trap mass spectrometers for in situ mass analysis by geometrically scaling traps to smaller sizes. This decreases the power and vacuum requirements which allows field portable instruments to use smaller/less powerful vacuum pumps and batteries. This dissertation presents the process of miniaturizing the planar linear ion trap (PLIT) to a microscale radius in order to investigate the scaling limits of mass spectrometers. The ultimate end goal is the integration of a PLIT into a portable mass spectrometry system. The PLIT consists of two flat, non-conducting plates, on which fine metal electrodes are patterned using standard microfabrication processes, including photolithography. An RF field is distributed across the electrodes to create a quadrupole electromagnetic potential which traps ions based on their mass to charge ratio. While simple in concept, the PLIT has been developed over a ten-year period including an investigation of a variety of substrate materials and design geometries. This dissertation briefly reviews the optimal fabrication flow and why the stated parameters have advantages over other possible combinations in a coplanar ion trap. Since ion trap miniaturization reduces the trapping volume (which also worsens the SNR and resolution of a mass spectrum), a novel RF phase tracking circuit was developed to exploit a phase locked condition during double resonance ejection. This was implemented on the PLIT to increase SNR before constructing the µPLIT. Better than unit resolutions (0.5 Da, FWHM) and SNR improvements were observed.Lastly, the successful miniaturization of the PLIT to a microscale radius is presented. This was done by redesigning the electrodes on the PLIT surface to have an equivalent trap radius (ro) of 800 μm. The μPLIT successfully confined then resonantly ejected ions with resolutions of approximately 2-3 Da. The performance of the μPLIT was also tested over a range of pressures from 2.5-42×10-3 Torr and retained resolutions between 2.3-2.7 Da. Ultimately, the μPLIT was shown to retain resolutions viable for portable mass spectrometry at pressures in the tens of millitorr while consuming a factor of 3.38 less power than the unscaled PLIT.

The rapid development of microelectronics has equally rapidly increased the demand for miniaturized energy storage devices. On-chip micro-supercapacitors (MSCs), as promising power candidates, possess great potential to complement or replace electrolytic capacitors (ECs) and microbatteries (MBs) in various applications. Recently, planar two-dimensional (2D) MSCs, composed of isolated thin-film microelectrodes with extremely short ionic diffusion path and free of separator on a single substrate, have become particularly attractive because they can be directly integrated with microelectronic devices on the same side of a flexible substrate to act as a standalone microsized power source. However, the areal capacities and energy densities of the 2D MSCs are commonly limited by the low voltage window and the thin layer of the electrode materials. Obviously, integrating more active material into cleverly designed three-dimensional (3D) electrode architectures will effectively increase the areal performance within a limited footprint area in spite of some loss of flexibility and cycling stability. However, it is still a big challenge to effciently and cost-effectively fabricate on-chip MSCs with high electro-chemical performance and abundant electrode structures. Here, three types of MSCs including graphene-based 2D planar MSCs, on-chip 3D interdigital MSCs and self-assembled 3D tubular MSCs were fabricated, respectively. The fabrication process, electrode materials structure and morphology, electrochemical performance, mechanical properties, integration process and difficulty, and practical application of these 2D and 3D devices are studied in detail.

With the increasing demand of compact and lightweight wireless devices, there is a significant need to miniaturize the antennas, which are one of the largest radiofrequency components. The radiation performance of antennas degrades as their physical size becomes smaller in terms of operating wavelength [1]. The key challenge in antenna design, therefore, lies in the compromise between size and radiation performance. This challenge becomes critical for low frequency antennas such as for the RFID band. The Antenna-in-Package (AiP) concept, where the antenna is realized as part of the package along with the driving electronics, provides some console in terms of size as the antenna does not need any additional space. In this approach, the package becomes a functional module along with its primary job of protecting the components from the environment. This work aims to investigate various miniaturization techniques for a UHF RFID tag on package. Firstly, a dipole is given a 3D shape by carefully folding it over a package, in a manner that the currents on different segments add constructively. Secondly, the package material (which acts as the substrate for the antenna) is chosen to have a dielectric constant of 5.3 which further helps in size reduction. Finally, loading of slow-wave structures, comprising of inductors and capacitors, is used to achieve further miniaturization. The Artificial Transmission Line approach is utilized to determine the required values of the lumped components, and its location is optimized by analyzing the current distribution of the antenna to maintain a good efficiency. The RFID chip with a large capacitive impedance is conjugately matched to the antenna without an external matching network. This is done by carefully selecting the values of the lumped components as well as by adjusting the trace width of the antenna. The package has been realized through a low-loss filament (𝑡𝑎𝑛(𝛿) = 0.004) with the Raise3D Pro2 printer, and the conductor has been realized by copper tape using laser patterning technology with the laser platform PLS6MW. At an operational frequency of 866 MHz, a 𝑘𝑎 of 0.26, a read-range of 2.7 𝑚, and a radiation efficiency of approximately 32% is achieved.

There is an increasing interest in using new composite materials in microwave devices, to reduce size and weight while maintaining similar performances. A new promising material group is named magneto-dielectric materials, which have the permittivity and permeability values both larger than one. Compared to the commercially used dielectric materials, magneto-dielectric materials can achieve a larger miniaturization factor with the equivalent properties as dielectric materials. There is a very limited availability of commercial magneto-dielectric materials. A recent addition was from Rogers Corporation with MAGTREX 555, [1], that is available as a printed circuit board laminate. The material is limited to 500 MHz operational frequency due to its increased magnetic and dielectric losses. In this thesis the purpose is to understand the loss mechanisms, characterize and understand the state-of-the-art magneto-dielectric materials at microwaves, and to produce a magneto-dielectric material in the lab to understand the material better. A new material was developed with magneto-dielectric properties. The material was based on a polymer base of polystyrene that serves as a dielectric material and doped with nickel nanoparticles that produce the magnetic properties. The contents of the nanoparticles in the mix is a design variable. Nickel-polystyrene samples with different nickel contents of 0%, 2.3% and 4.5%, were produced in the lab and measured in-house to understand the loss mechanism and RF performance.

Du fait de la disponibilité de capteurs éléctroniques de plus en plus puissant, la dernière décennie a vu la popularisation de nouveaux dispositifs mobiles, comme les téléphones intelligents (smartphone), et même des dispositifs miniatures comme ceux de l'informatique portée. Ces nouveaux dispositifs apportent de nouveaux problèmes interactionnels, du fait de la petite taille de l'écran et du problème du "fat-finger" (lors de l'interaction, une large portion de l'écran se retrouve occultée par le doigt, et les tâches de pointage perdent en précision. L'objectif de ce travail est double : 1) d'acquérir une meilleure compréhension du pointage sur les petits dispositifs mobiles, grâce à une étude poussée de la loi Fitts, 2) de créer de nouvelles techniques d'interaction afin d'augmenter la bande passante interactionnelle entre l'utilisateur et le dispositif / Thanks to the availability of powerful miniaturized electronic coponents, this last decade have seen the popularization of small mobile devices such as smartphones, and even smaller devices for wearable computing. These new devices bring new interaction problems, such as the small size of the screen and the "fat-finger" problem (a relatively large portion of the sreen is occluded and pointing lacks precision). the objective of the work reported here is twofold : 1) to aquire a better understanding of pointing on small devices, thanks to an advanced study of Fitts' law, 2) to design new interaction techniques for increasing the interaction bandwidth between the user and the device.

A new approach of making ion trap mass analyzers was developed in which trapping fields are created in the space between two ceramic plates. Based on microfabrication technology, a series of independently-adjustable electrode rings is lithographically patterned on the facing surfaces of each ceramic plate. The trapping field can be modified or fine-tuned simply by changing the RF amplitude applied to each electrode ring. By adjusting the potential function applied to the plates, arbitrary trapping fields can be created using the same set of ceramic plates. Unlike conventional ion traps, the electrodes of planar ion traps have a non-equipotential surface, thus the electric field is independent of electrode geometry and can be optimized electronically. The simple geometry and open structure of planar ion traps address obstacles to miniaturization, such as fabrication tolerances, surface smoothness, electrode alignment, limited access for ionization or ion injection, and small trapping volume, thereby offering a great opportunity for a portable mass spectrometer device. Planar ion traps including the planar quadrupole ion trap and the coaxial ion trap have been designed and tested using this novel method. The planar quadrupole trap has demonstrated a mass range up to 180 Da (Th), with mass resolution typically between 400-700. We have also developed a novel ion trap in which both toroidal and quadrupolar trapping regions are created simultaneously between a set of plates. This "Coaxial Trap" allows trapping and mass analysis of ions in two different regions: ions can be trapped and mass analyzed in either the toroidal or quadrupolar regions, and transferred between these regions. Some simulation work based on the ion motion between two different trapping regions in the coaxial ion trap has been performed. Using a one-dimensional simulation method, ion motion was investigated to transfer ions between these two regions. The effect of the mutipole components in the radial field and axial field, amplitude and frequency of the primary RF and supplementary AC signal were studied to obtain high mass resolution in the axial direction and high transfer efficiency in the radial direction. In all these devices, the independent control of each patterned electrode element allows independent control of higher-order multipole fields. Fields can be optimized and changed electronically instead of physically as is done in conventional traps.

Yes / In this paper, a pyramidal horn antenna loaded with unit cell of metamaterial is proposed, designed and realized for L-band that including terrestrial digital audio broadcasting TDAB, GPS and GSM. The proposed antenna operates in the frequency range from 1.722 GHz to 1.931 GHz. The metamaterial is fabricated on a printed circuit board as Capacitive Loaded Loop (CLL). The work aims to exhibit the advantage of metamaterial loaded inside the horn antenna in terms of the gain enhancement of the radiation pattern and the resonant frequency shift towards lower frequency. The retrieval technique used show that the constitutive parameters of the unit cell as CLL have a zero index metamaterial (ZIM) from 1.34 GHz to 1.49 GHz and a near zero index of refraction from 1.495 GHz to 2 GHz, which is within the operating frequency of the horn antenna. The achieved results show that the total gain is improved over the frequency range. The simulation and the measurement are in good agreement.