Cadmium Zinc Telluride (CdxZn1-xTe or CZT) is a ternary semiconductor with a tunable bandgap of 1.44-2.26 eV. Solar cells with efficiencies of 20% or higher can be achieved by using a tandem solar cell structure which consists of a top cell and a bottom cell connected in series. In this kind of a structure, the light passes through the top cell first which has a wider bandgap to absorb light of shorter wavelengths and the remaining light passes through the bottom cell with a lower bandgap to absorb light of higher wavelengths. For a tandem cell structure, the ideal bandgap for the top and bottom cell is 1.7 eV and 1 eV respectively. Cadmium Zinc Telluride is a suitable candidate for the top cell and Copper Indium Gallium Diselenide (CIGS) with a bandgap of around 1 eV is a suitable candidate for the bottom cell. This work involves characterization and optimization of CZT solar cells by Close Spaced Sublimation (CSS). Cadmium Zinc Telluride is deposited by the co sublimation of Cadmium Telluride (CdTe) and Zinc Telluride (ZnTe) chunks. Cadmium Zinc Telluride solar cells were fabricated using Tin Oxide (SnO2), Zinc Oxide (ZnO) and Zinc Stannate (Zn2SnO4) films as substrates. The as-deposited CZT films were studied by XRD, EDS and SEM measurements. The devices were characterized by Current-Voltage (I-V) and Spectral Response measurements.

CdTe films were deposited by sputtering technique and were then carried out by CdCl2 treatment. The SEM micrographs show that the grain sizes of the as-deposited CdTe film were normally ranged from 50 nm to 100 nm, and they were recrystallized after CdCl2 treatment to obtain the grain sizes in the range of 1~3 £gm. A new device structure for CdTe thin-film solar cells has been proposed to exceed the cell efficiency of current record. The superstrate structure with the layer sequence of Glass/AZO/ZnO/CdS/CdTe/CI(G)S/Mo compared with the conventional device structure of Glass/FTO/CdS/CdTe/metal contact would have the following advantages:(1) a highly conductive AZO layer combined with a thin undoped ZnO layer will have higher optical transmission than that of FTO; (2) the use of p-type CIS under the CdTe layer with the same conductivity type can extend the light absorption to longer wavelength range (the band gaps of CdTe and CIS are 1.45eV and 1.04eV, respectively); (3) the proper addition of Ga to CIS may form CIGS quaternary compounds with a bandgap gradient which produce an electric field in the neutral region of a p-n junction to reduce the carrier recombination; (4) the use of Mo contact to CI(G)S is quite stable as compared with the metal contact normally used for p-CdTe. AMPS-1D simulation had been applied to evaluate the newly designed device structure and the results indicated a great improvement in device performance, i.e. the cell efficiency could exceed 20%. The I-V curve of a CdTe solar cell using the new device structure showed a nearly linear characteristic indicating the failure to form a p-n junction. We speculated that Cu might diffuse through the CdTe layer to the depletion region of the p-n junction formed at the CdS/CdTe interface. This would cause the junction failure. Based on the calculation on the Cu diffusion during the deposition of CIS layer at different temperatures even as low as 150˚C, it always had the chance to diffuse through the CdTe layer. An alternate device fabrication process was the use of the substrate structure for preparing CdTe solar cells, i.e. Glass/Mo/CIS/CdTe/CdS/ZnO/AZO/Al. However, the desired diode behavior was not observed until the thickness of CdTe layer was cut down to 10 nm. The electrical properties of that particular solar cell is the following:Voc=0.36V, Isc=4.991mA/cm2, F.F.=25.3%, efficiency=0.472%. It is probably that the lattice mismatch between CIS and CdTe is large that may cause the formation of interfacial defects and the reduction of photo excited carriers through the recombination processes. The annealing processes had been conducted in order to promote the interdiffusion between CdTe and CIS and minimize the lattice mismatch. However, the films peered off after annealing. Further experiments should be done to solve this problem.

Differences between indoor non-contact vital sign sensor and general sensors are ¡§indoor¡¨ and ¡§vital sign¡¨. In indoor environment, receiving signals encounter multipath problem caused by the reflection of walls and furniture. Two main vital signs that we are concerned with are heartbeat and respiration; both of them are weaker than general signals used in communication. To overcome problems caused by multipath and weak signal strength, in this thesis, we design a narrow beamwidth antenna operating at 2.45 GHz for indoor non-contact vital sign sensor. We propose a ground surrounded antenna (GSA) which differs from traditional slot and patch antenna. The proposed GSA excites slot mode and patch mode at the same time, so that we can achieve dual-bands or wide band by adjusting its physical parameters. Meanwhile, the reflected wave bounced back from the surrounding ground plane can cause constructive interference so that the antenna possesses better gain and beamwidth. Using GSA as the unit antenna of antenna array to achieve narrow beamwidth design, and adding the concept of superstrate can enhance antenna gain and reduce backlobe radiation. The minimum beamwidth at two orthogonal planes are 26 and 52 degrees respectively, and the antenna gain achieves 12.2 dBi. To reduce the interference between receiving and transmitting signals in single antenna, we use two separate antennas. Finally, we discuss and improve isolation problem between two antennas.

La traduction est une activité linguistique qui joue un rôle primordiale dans la vie des différentes communautés humaines. Considérée comme moyen de communication et de connaissance de l’autre, plusieurs disciplines lui ont été consacrées. Au XVIIIème siècle, la faculté des langues (al-Alsun) a été instaurée en Égypte par Rifāʽa al-Tahtāwī, l’auteur de Taḫlīṣ al-ibrīz fi talḫlīṣ Bārīz. Cette œuvre a été traduite au XXème siècle par Anouar Louca sous le titre de l’Or de Paris. L’Étude présente porte sur une œuvre qui présente une description minutieuse du séjour de Rifāʻa al-Ṭahṭāwī en France, à savoir le Taḫlīṣ al-ibrīz fi talḫīṣ Bārīz. Cette œuvre appartient à l’époque de la Nahḍa de la littérature arabe.L’étude porte sur quatre chapitres : Le premier chapitre entame analyse esthétique comparée du Taḫlīṣ et de l’Or de Paris. Le chapitre explique les manifestations des deux versants de la Nahḍa dans le Taḫlīṣ et les stratégies adoptées par Louca dans son Or de Paris.Le deuxième chapitre présente une analyse sociolinguistique du Taḫlīṣ et de l’Or de Paris. Cette analyse met en lumière le lien intrinsèque entre la langue et la société. Une comparaison de l’œuvre dans sa langue source et sa traduction mettra l’accent sur la stratégie de Louca et sur les différences entre l’original et la traduction.Le troisième chapitre porte sur la problématique de la fidélité selon la théorie interprétative. La marge de liberté et les procédés utilisés par Louca seront discutés. Le quatrième chapitre est une analyse sémantique sélective d certains passages dans le Taḫlīṣ et leurs représentations dans l’Or de Paris. L’analyse va porter sur le titre, le premier paragraphe et la traduction faite par Rifāʻa al-Tahtāwī de la charte constitutionnelle de 1814. Les quatre chapitres procèdent par une mise en parallèle de l’œuvre original et de sa traduction.Nous reconnaissons la difficulté de la tâche assumée par Louca vu la richesse de l’œuvre de Rifāʻa al-Tahtāwī qui représente un tournant dans l’histoire de la littérature arabe. La spécificité culturelle, esthétique, historique et linguistique constitue un vrai défi à la traduction. / Translation is a linguistic activity which plays an essential role in the life of various human communities. Considered as a tool of communication and knowledge of the others, several disciplines were dedicated to it. In the XVIIIth century, the faculty of languages (al-Alsun) was established in Egypt by Rifāʽa al-Tahtāwī, the author of Taḫlīṣ al-ibrīz fi talḫlīṣ Bārīz. This work was translated in the XXth century by Anouar Louca under the title of “L’Or de Paris” which means “The Gold of Paris”. The study hereby presented deals with a work that presents a meticulous description of the journey of Rifāʻa al-Ṭahṭāwī in France. The latter work is Taḫlīṣ al-ibrīz fi talḫīṣ Bārīz and belongs to the period of Nahḍa of the Arabic literature.The study consists of four chapters: The first chapter presents a comparison between the aesthetic analysis from Taḫlīṣ and its translation, namely Or de Paris, into the french langage. The chapter explains the demonstrations of both objectives of the Nahḍa in the Taḫlīṣ and the strategies adopted by Louca in his Or de Paris.The second chapter presents a sociolinguistic analysis of Taḫlīṣ and Or de Paris. This analysis highlights the intrinsic link between the language and the society. A comparison of the Taḫlīṣ in its original language and its translation emphasizes the strategy of Louca and the differences between the original work and its translation.The Third chapter discusses the problem of the loyalty according to the interpretative theory. The room for manoeuvre and the processes used by Louca will be discussed.The fourth chapter is a selective semantic analysis of certain passages in Taḫlīṣ and their translations in Or de Paris. The analysis concerns the title, the first paragraph and the translation of the constitutional chart of 1814 made by Rifāʻa al-Ṭahṭāwī. The Four chapters proceed in a parallel pattern between the original work Taḫlīṣ and its translation.We recognize the difficulty of the task carried out by Louca given the wealth of the work of Rifāʻa al-Ṭahṭāwī which represents a bend in the history of the Arabic literature. The cultural, aesthetic, historical and linguistic specificity constitute a real challenge in the translation.

This thesis deals with microstrip antennas covered by the metamaterials. First, are described planar antennas, their problems and the emergence of surface waves. Surface waves can cause unwanted coupling among particular parts of the structure and can degrade its parameters. The problem can be solved using an electromagnetic band gap structure (EBG). These periodic structures are able to suppress surface waves in different frequency bands. It is shown how the EBG structure in the function superstate improve directivity and antenna gain. Radiation conventional microstrip antenna with metallo-dielectric EBG superstrate and with the purely dielectric double-layer superstrate is described. The both structures are designed and simulated in CST Microwave Studio program. Further is described the antenna radiation with so-called mushroom structure and metallo-dielectric EBG superstate. The structure is again designed and simulated in CST MWS program. Finally, there are two structures with metallo-dielectric superstate implemented and measured.

No description available.

La Transformation d’Espace appelée aussi Transformation Optique (TO) est un outil de conception électromagnétique puissant qui a permis la conception de nouveaux dispositifs tels que la célèbre “cape d'invisibilité”. Cette thèse s’inscrit dans la continuité directe de celle de M.D. Clemente Arenas (Application de la transformation d'espace à la conception d'antennes à diagramme de rayonnement contrôlé, 2014) et porte sur l’utilisation de la TO pour modifier drastiquement le rayonnement d’une antenne patch. Ces fortes modifications du rayonnement sont habituellement obtenues avec l’aide d’un superstrat encombrant et constitué de matériaux ayant une perméabilité et permittivité exotiques (métamatériaux). L’objectif est donc ici de réduire cet encombrement et de simplifier la réalisation en utilisant des matériaux diélectriques standards. Ainsi, grâce au superstrat développé, une antenne patch ayant un gain réalisé de 7 dB devient une antenne présentant deux lobes dans le plan azimutal de gain réalisé de 3.5 dB. Le superstrat, d’épaisseur 0.12λ, est conçu à l’aide de deux matériaux uniquement : Alumine (εr = 9.9) et Fullcure (εr = 2.8), alors que le profil initial comporte une permittivité variant entre 1 et 15 et une perméabilité entre 0.3 et 3. Divers degrés de libertés dans la conception permettent d'adapter notre solution pour concevoir d’autres superstrats avec des fonctionnalités différentes: diagramme ayant une ouverture de plus de 180° dans un plan, diagramme end-fire, etc. Les applications visées sont notamment celles de l’aéronautique pour lesquelles il existe aujourd’hui sur les aéronefs plusieurs dizaines d’antennes pour assurer toutes les liaisons nécessaires aux communications, à l’identification, au positionnement, etc. La géométrie du porteur conduit alors à utiliser plusieurs antennes protubérantes pour remplir cette mission. Cependant pour un avion, ces excroissances contribuent à dégrader l’aérodynamisme de l’appareil ce qui se traduit par une consommation plus importante. Le but est donc de proposer des solutions antennaires à rayonnement nonconventionnel et non protubérante compatible avec une intégration sur dérive ou fuselage. Le concept est validé à l'aide d'une maquette réalisée avec une imprimante 3D et avec le soutien d’Airbus Group Innovations. / Transformation Optics (TO) is a powerful electromagnetic design tool that enables the design of new devices such as the famous "invisibility cloak". This thesis is in direct continuation of that of M.D. Clemente Arenas (Application de la transformation d'espace à la conception d'antennes à diagramme de rayonnement contrôlé, 2014) and focuses on the use of the TO to drastically change radiation of a patch antenna. These sharp changes in radiation pattern are usually obtained using bulky superstrates made of metamaterials having exotic permeability and permittivity values. The objective of this thesis is to reduce the thickness of the superstrate and simplify the fabrication by enabling the use of standard dielectric materials. Thus, a patch antenna with realized gain of 7 dB is transformed, with the help of proposed superstrate, into an antenna having two lobes in the azimuth plane withrealized gain of 3.5 dB. The 0.12λ thick superstrate is designed using two standard dielectric materials only: Alumina (εr = 9.9) and FullCure (εr = 2.8), whereas the previous solution had variation in permittivity between 1 and 15 and in permeability between 0.3 and 3. Various degrees of freedom in the design allow adapting this solution to develop new superstrates for other applications: radiation pattern with HPBW greater than 180 ° in one plane, end-fire radiation pattern, etc. Target applications include those of aeronautics. Today, dozens of antennas on an aircraft are required to ensure the necessary communications links, identification, positioning and other purposes. The structure of the aircraft necessitates use multiple antennas to fulfill this mission, which are fixed and protrude on fuselage or wings. However, for an aircraft, these protuberances contribute to the aerodynamic drag, which results in higher fuel consumption. Therefore, the objective is to propose conformal antenna solutions with unconventional radiation pattern, which can be eventually integrated on fuselage or rudder. The concept is validated using a model made with a 3D printer and with the support of Airbus Group Innovations

This diploma thesis deals with the modeling of planar antennas with special superstrates in the CST Microwave Studio. Attention is given to the electromagnetic bandgap (EBG) substrates. Firstly, the working principle of these special substrates and generally physical phenomena accompanying electromagnetic waves propagation in a periodic medium are analyzed. By modeling of basic EBG structures in CST their dispersion diagrams were obtained and afterwards compared to one another. The object of the second part of this thesis was modeling of a chosen antenna in CST. An Antenna placed first on the conventional and then on the EBG substrate - in both cases with special superstrates - is analyzed and compared to each other. In the third part of this thesis, the particle swarm optimization (PSO) technique was implemented in CST (VBA language), and was applied to the original design of the chosen antenna. In the final part of this thesis, the optimized antenna was modeled and analyzed in ANSOFT HFSS, and the results from both simulation programs are compared to each other.

Planar antennas are used in several technical applications. The family of planar antennas contains microstrip antennas, which are very popular due to the low weight, low profile, simple manufacturing and easy mass production. Lower gain and excitation of surface waves are disadvantages of microstrip antennas. The propagation of surface waves can be efficiently suppressed if the conventional substrate is replaced by an electromagnetic bandgap (EBG) substrate. Microstrip antennas on EBG substrates have been presented in an open literature for several years. Nevertheless, no published work is devoted to the design of EBG substrates, which can suppress surface waves at several frequencies those cannot be covered by a single bandgap. In order to reach optimum parameters of designed antennas, selected global optimization methods are applied (genetic algorithms, particle swarm optimization, ant colony optimization).