Dissertations / Theses on the topic 'POLARIZER COMPONENTS'

The Polarizer-Sample-Analyzer (PSA) arrangement with the optical components P and A rotating with a fixed speed ratio (3:1) was originally introduced to determine nine Mueller matrix elements from Fourier analysis of the output signal of a photodetector. The arrangement is modified to the P'PSAA' arrangement where P' and A' represent fixed polarizers that are added at both ends with the speed ratio of the rotating components (P and A) remaining the same as before. After determination of the partial Mueller matrix in the ideal case, azimuthal offsets and imperfection parameters are introduced in the straight-through configuration and the imperfection parameters are determined from the Fourier coefficients. Finally, the sample is reintroduced and the full Mueller matrix elements are calculated to show the deviation from the ideal case and their dependency on the offsets and imperfection parameters.

This thesis treats of channel models for polarized multi-antenna wireless systems. Polarized multi-antenna systems are systems that use perpendicularly polarized, co-located antennas at the base station and at the mobile terminal, in order to benefit from the so-called polarization diversity. Such systems benefit from the advantages of MIMO systems while still maintaining a compact equipment size. Two models will be presented in this thesis. The first one is the Polarized-Input Polarized-Output (PIPO) channel model, the second one is the Polarized-Diffuse-Directional channel model.

The PIPO model is a statistical channel model for tri-polarized to tri-polarized communication systems. A tri-polarized antenna system is a tranceiver using three perpendicular antennas. The aim of the PIPO channel model is to have a model that has a simple mathematical structure, so it can be used for solving precoding equations or capacity calculations. Although the PIPO model has a very simple structure, it takes the following parameters into account: coherent channel component, cross-polar channel power imbalance, inter-channel correlation, short- and long-scale time variance.

Experimental measurements are used to parameterize the model. It is shown how the model parameters are extracted from experimental measurements, and the results are analyzed to allow further simplification of the model.

The PDD model, on the other hand, is a geometry-based stochastic channel model. It models the channel as a sum of clusters, where each cluster consists of groups of multipath components (MPCs). The PDD model includes two novelties that will be developed in detail in this thesis.

- The model considers polarization on a per-cluster basis. This permits to have a more accurate description of the polar-angular spectrum.

- The diffuse multipath component (DMC) is included by considering a diffuse component for each cluster. The diffuse cluster component is then modeled as the sum of a set of diffuse MPCs.

The model is specified in detail, and it is shown how the model can be generated.

Experimental measurements were carried out to parameterize the model. A new extraction technique for extracting the specular-diffuse clusters from the measurements is proposed. This technique is based on joint clustering of the specular MPCs and the bins of the diffuse component. The experimental results are analyzed, and superimposed with environment information to gain further insight into the physical aspects of clustered propagation.

Finally, both models are validated. Several validation metrics are introduced, and their pertinence in the context of polarized MIMO systems is highlighted. Both models are successfully validated, and the advantages and limitations of each models are investigated.

Cette thèse traite des modèles de canal pour systèmes sans-fils multi-antennes polarisés. Des systèmes multi-antennes polarisés sont des systèmes qui utilisent des antennes polarisées perpendiculairement co-localisées à la station de base et au terminal mobile, dans le but de bénéficier de la diversité de polarisation. De tels systèmes peuvent bénéficier des avantages des systèmes MIMO tout en diminuant l'encombrement des équipements. Deux modèles seront présentés dans cette thèse. Le premier est le modèle Polarized-Input Polarized-Output (PIPO), le second est le modèle Polarized-Diffuse-Directional (PDD).

Le modèle PIPO est un modèle statistique pour des systèmes de communication tri-polaire à tri-polaire. Un système tri-polaire est un émetteur ou un récepteur qui utilise trois antennes perpendiculaires. Le but du modèle de canal PIPO est d'avoir un modèle qui a une structure mathématique simple, afin qu'il puisse être utilisé pour résoudre des équations de précodage ou des calculs de capacité. Malgré la structure simple du modèle PIPO, il tient compte des paramètres suivants: la composante cohérente du canal, les différences de puissance entre canaux cross-polaires, la corrélation entre canaux, les variations à courte et à longue échelle de temps. Des mesures expérimentales ont été réalisées afin de paramétriser le modèle. Les techniques pour extraire les paramètres du modèle des mesures expérimentales sont présentées, et les résultats sont analysés afin de permettre une simplification supplémentaire du modèle.

Le modèle PDD, quant à lui, est un modèle de canal stochasique-géométrique. Il modélise le canal comme une somme de clusters, où chaque clusters est composé d'un groupe de chemins multi-trajets. Le modèle PDD inclut les deux nouveautés suivantes qui seront développées en détail dans cette thèse.

- Le modèle considère une polarisation par cluster. Ceci permet d'avoir une description plus exacte du spectre angulaire-polaire.

- La composante diffuse est prise en compte en incluant une composante diffuse pour chaque cluster. La composante diffuse d'un cluster est alors modelisée comme une somme de multi-trajets diffus.

Le modèle est spécifié en détail, et il est présenté comment le modèle peut être généré. Des mesures expérimentales ont été faites afin de paramétriser le modèle. Une nouvelle technique d'extraction est proposée pour extraire les clusters spéculaires-diffus. Cette technique est basée sur le clustering conjoint des multi-trajets spéculaires et des "bins" de la composante diffuse. Les résultats expérimentaux sont analysés, et superposés avec l'information de l'environnement de mesure afin d'avoir une connaissance accrue des aspects physiques de la propagation par clusters.

Finalement, les deux modèles sont validés. Plusieurs métriques de validations sont introduites, et leur pertinence dans le cadre des systèmes MIMO polarisés est mis en avant. Les deux modèles sont validés avec succès, et les avantages et limitations de chaque modèle sont investigués.

Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished

The Gram-positive bacterium Streptomyces coelicolor, is one of the main genetic model organisms in the phylum of the Actinobacteria. Streptomyces bacteria are soil dwelling filamentous bacteria with a complex life cycle consisting of multigenomic hyphae that then form unicellular spores. Bacterial cell shape determination has been influenced heavily by the discovery that bacteria have a number of eukaryotic cytoskeletal homologues as well as a number of accessory proteins unique to prokaryotes. As cell shape determination is dependent on the sites of insertion of new cell wall material, this is characteristically organised and driven by cytoskeletal proteins. Streptomyces coelicolor hyphal growth occurs through apical extension where new cell wall material is placed at the tips. This growth is driven in part by the cytoskeletal protein DivIVA. Here we characterise a novel Streptomyces cytoskeletal protein, Scy, encoded by the locus sco5397. Scy is a large protein with a novel coiled-coil 51-mer repeat structure. To study Scy, a scy knockout mutation was generated. The phenotype of the scy mutant suggests that it plays a significant role in cell shape, growth and chromosome positioning. Translational fluorescent protein fusions to scy were made and the subcellular localisation of Scy was determined to be strongly at growing hyphal tips. Further clarified here, Scy overexpression can recruit DivIVA protein and the cell wall synthesis machinery to new apical sites. The reciprocal is also shown whereby DivIVA overexpression can recruit Scy to new apical sites. Further to this in vivo and in vitro experiments were performed to determine that Scy and DivIVA interact, as well as the protein FilP encoded downstream of scy. The work here along with work in the field suggests that Scy forms part of a Tip Organising Centre (TIPOC) that alongside DivIVA, FilP, and numerous other proteins controls apical growth in the filamentous Streptomyces.

In the recent astrophysical experiments i.e. QUIET, QUIJOTE, STRIP-LSPE, arrays of polarimeters are used in order to measure the linearly polarized component of the Cosmic Microwave Background Radiation (CMBR). Since the signal of interest is very faint, the sensitivity of the scientific instrumentation should be very high. This goal can be achieved by accommodating a large number of high-performance polarimeters in the focal plane of the antenna. In this perspective, a novel layout of Ortho-Mode-Transducer (OMT) and polarizer, which are key passive waveguide elements of dual-circular polarization polarimeters, have been designed. The polarizer is based on a Dual-Fold-Stub (DFS) design having 20% bandwidth centered at 94.5GHz, whereas the broadband OMT exploits a turnstile junction with 30% bandwidth centered at 94 GHz. The components are realized using the multi-layer technology, where each metallic plate is manufactured by wire spark erosion technique. Using this design methodology, several identical devices can be manufactured in a single machining process. The exploitation of multi-layer technology in conjunction with wire spark erosion technique provides high level of manufacturing repeatability and accuracy along with low cost, making this solution well suitable for the realization of polarimetric arrays consisting of tens/hundreds of chains. The propriety SEM (Spectral Element Method) tool of IEIIT-CNR and commercial EM (Electromagnetic) tools (CST-MWS & HFSS) have been exploited in an effective manner to achieve the required performances. In order to integrate MATLAB with EM tools, COM EM Automation Tool (COM-EM-AT) has been developed and exploited in various manner to attain the final design. The simulation acceleration through distributed computing have also been employed efficiently for tolerance analysis using the SEM tool.

In this work, we demonstrate an inimitable liquid crystalline template strategy for the preparation of water dispersible electrically conducting poly(3,4-ethylenedioxythiophene) nanospindles (PEDOTSs). PEDOTSs were formed during the polymerization of the spindle shaped liquid crystalline phase of “EDOT–PDPSA” which was formed by the specific interactions of 3,4-ethylenedioxythiophene (EDOT) with 3-pentadecyl phenol-4-sulphonic acid (PDPSA). Liquid crystalline phases were characterized by Polarized Light Microscopic (PLM) analyses, rheology and XRD. Morphology and solid state ordering of conducting nanospindles were characterized by SEM, TEM and XRD. PEDOTSs exhibited an electrical conductivity of ~2.79 S cm⁻¹ and a good thermal stability (~300 °C), which suggests their applicability in fabricating high temperature electronic devices. Furthermore, electrochemical studies of PEDOTS modified glassy carbon electrodes (GCEs) showed an oxidation peak of ascorbic acid at a lower potential of 0.046 V with a peak current about 10 times (91.68 µA) higher than that of the bare GCE with excellent electrode stability, proposing that it can be used as a steady electrode for the electro-catalytic oxidation of similar molecules.

碩士
國立交通大學
材料科學與工程學系
100
Polarizer light leakage occurred on LCD panel after thermal and/or moisture reliability test, since the shrinkage of the PVA film induced stress and strain generated in the polarizer. Light leakage deteriorated as larger panels were introduced for better visual quality. Therefore, how to improve the material properties of polarizer components is one of the critical tasks in current research. In this study, 3-D finite element analysis models using ANASYSTM was first established to examine the stress and deformation of the polarizer after the reliability test in order to explore their correlation with the light leakage phenomenon. In addition to have the accurate result, MTS, TMA, DMA and home made bending beam system were used for measuring the thermomechanical and viscoelastic properties of polarizer components for simulation input. Specifically, the root cause of polarizer light leakage was examined and proposed. Then, the impact of thermomechanical and viscoelastic properties of PSA and TAC was investigated. Based on experimental data and numerical analysis, a strong relationship among light leakage and stress distribution on the TAC film has been established. Beside, the root cause of polarizer light leakage is proposed. The polarizer light leakage appeared due to the retardation difference in the TAC film induced by thermal and/or moisture shrinkage of the polarizer. Moreover, the stress relaxation behavior of PSA has been found to be the critical factor for affecting the time-dependent polarizer light leakage variation. Numerical modeling was also utilized to analyze the material design direction on polarizer light leakage improvement. Increasing the Young’s modulus of the PSA layer can effectively reduce the shrinkage of polarizer and also diminish center light leakage of the panel, and an effective solution can be achieved with low modulus and/or low CTE TAC film. Finally, using low stress relaxes ability and low moisture absorbability PSA layer can provide stable display quality.

博士
國立交通大學
材料科學與工程學系所
103
In this study, we combine the stress measurement using bending beam technique with static thermal-dependent and transient time-dependent three-dimensional (3D) finite element analysis (FEA) analysis to examine the light leakage variation of the thin-film transistor liquid-crystal display (TFT-LCD) panel. The objective is to understand the effects of material properties of key components, temperature, and humidity under hygrothermal reliability test on the light leakage phenomena. The shrinkage stress in stretched poly(vinyl alcohol) (PVA) film and stress relaxation ability of pressure-sensitive adhesives (PSA) layers are found to be the key factors determining the stress distribution and out-of-plane displacement of a polarizer stack. For hard-type PSA, its polarizer stack generates the highest bending curvature with maximum out-of-plane displacement but minimum in-plane displacement, leading to anisotropic stress distribution with high stress around the edges. On the other hand, polarizer stack with soft-type PSA yields the maximum in-plane displacement but the minimum out-of-plane displacement, resulting in isotropic stress distribution. 3D FEA shows that a strong correlation exists between light leakage and retardation difference induced by stress on triacetyl cellulose (TAC) films. For hard-type PSA, the area of higher principal stress difference is relatively small and localized on the edges of the panel, thus indicating low dimensional variations. In contrast, funnel-type light leakage and greater polarizer shrinkage are found for soft-type PSA. Moreover, the magnitude of hygroscopic stress in the simulated analysis is found to be significantly higher than that of thermal stress. This can be attributed to moisture’s plasticizing effect on the hydrophilic polymers such as PVA and PSA layers, leading to enhanced stress relaxation and degradation of the display image quality. An increase in Young’s modulus of PSA brings in lower relaxation ability and better resistance to shrinkage in polarizer stack, making it an effective solution to minimize the light leakage. The other effective solution is to develop a TAC film with lower Young’s modulus and/or lower coefficient of thermal expansion (CTE).

碩士
國立臺灣大學
電信工程學研究所
91
In the thesis, we propose the design of two passive components, filters and polarizers that are crucial in microwave communication systems. Based on the theory of ring resonator filters, we propose a novel CPW-fed step-perturbed slot ring filter, which possesses the merits of small size, narrow bandwidth, and high quality factor as the conventional ring resonator filter does. The filter, it does not need the via hole process in fabrication and hence can be widely used due to its uni-planar feature. It shows good agreement for the simulated and measured results. For the polarizer, we employ a septum polarizer that is not so sensitive as the conventional one does. A novel design procedure is proposed to achieve the broadband characteristics. Besides, the performance can be fine tuned by simply adjusting the length of the septum.

First we investigate the generation of non-classical states of light by means of pulsed parametric down-conversion, and second their complete diagnostics and characterisation by means of pulsed homodyne detection. We introduce a new characterisation technique of quantum states of light (starting with the case of the single photon) that combines techniques from the fields of quantum optics and ultrafast coherent control: the idea is to generate femtosecond quantum light states with a broad spectrum, and then, through adaptive mapping of their spectro/temporal mode onto the reference field, to completely retrieve the "shape" of the state under investigation, even with no prior information at hand. The possibility of accessing the arbitrarily-shaped spectro/temporal structure of ultrashort quantum light states will allow a leap forward to the encoding and manipulation of quantum information.

碩士
國立中山大學
高階經營碩士班
95
TFT-LCD industry has been developing rapidly in Taiwan over last several years. Because of a large amount of investment and output value in TFT industry, it become one of the most important industry which droved relative industrial development. Japanese and Korean are known as the leading manufacturers in TFT-LCD industry. The TFT-LCD firms in Taiwan suffered difficult industrial environment. They compete with both Japanese and Korean, and earn low or negative profits. What are the company’s prior strategic commitments in the face of environmental change? The purpose of this paper is to study TFT-LCD firms about their business model and strategic performance, and try to analyze the key factor of success basing on strategic management theory including “five force model”, “resource-based theory” and “resource dependence theory” etc. We may learn some lessons from firm’s experiences both of success and failure, and find out why some business can be so successful and some else can’t. Another important aspect of this study is to assess TFT-LCD firms’ strategic performance basing on financial information, and analyzed the relation between business strategy and financial performance. For a company to have distinctive competency, it must at a minimum have either “a unique and valuable resource and the capabilities necessary to exploit that resource ” or “a unique capability to manage common resources”. A company’s distinctive competence is strongest when it possesses both unique and valuable resources and capabilities to manage those resources. This study tries to contribute to competitive advantage of Taiwan’s TFT-LCD industry.

[ES] En el presente trabajo, se investigan algunos aspectos de la interacción de los materiales dieléctricos con ondas de THz. La banda de THz, que incluye las frecuencias de 100 GHz a 30 THz, ha despertado un gran interés sobre todo por su baja energía y su buena capacidad de penetración en materiales de uso diario como tejidos y plásticos. Las características peculiares de estas ondas permiten su aplicación en diversos campos tecnológicos, especialmente como herramientas científicas y para la inspección de control de calidad. Para avanzar en la aplicación práctica de la radiación THz, la presente tesis doctoral investigó varios caminos. En primer lugar, se trataron métodos alternativos de bajo coste para la fabricación de componentes pasivos de THz, centrándose en los polarizadores. El interés en el control de la polarización nace de la demanda de un mayor control sobre las características físicas de los haces de THz. Asimismo, se han investigado los polarizadores wire grid flexible basados en el efecto de absorción dicroica. Se han fabricado polarizadores con grafito y GaIn24,5 depositados en materiales ordinarios utilizados como sustratos (papel y polímeros como PVA y PVC). Mediante la colaboración con el grupo de investigación chino dirigido por el profesor Liu de la Universidad de Tsinghua, se investigaron procesos de fabricación alternativos. Todos los componentes se simularon mediante un simulador comercial basado en la técnica de integrales finitas FIT (CST Microwave Studio). En segundo lugar, se investigó el potencial de la técnica de fixed delay para la detección rápida de elementos homogéneos y transparentes con posible aplicación en la inspección de calidad industrial. En este esquema, la variación de corriente del haz de THz en un punto específico está relacionada con la variación de sus parámetros ópticos, por lo que se demostró la capacidad de detectar defectos, así como de estimar sus volúmenes bajo ciertas condiciones. Por último, un enfoque diferente para el beam profile basado en un slit dieléctrico fue evaluada como alternativa a los métodos convencionales utilizados en la región de THz y la óptica. Todas las mediciones, tanto la espectroscopia como el control de la polarización, se hicieron por medio de un sistema basado en fibra TDS-THz, con antenas fotoconductoras (PCA), tanto para la generación como para la detección de THz.
[EN] In the present work, some aspects of the role of dielectric materials when interacting with THz waves were investigated. The THz bandgap, which covers the frequencies from 100 GHz to 30 THz, has aroused great interest mainly due to its low energy and its good penetration capacity in some materials of daily use such as fabrics and plastics. The peculiar features of terahertz waves enable their application in various technological fields, especially as scientific tools and for quality control inspection. To advance in the practical application of THz radiation, the present doctoral thesis researched several paths. Firstly, alternative low-cost methods for manufacturing THz passive components, in particular, THz polarizers was treated. The interest in polarization control is derived from the demand for greater control over the physical characteristics of THz beams. Flexible wire grid polarizers based on the dichroic absorption effect have been investigated. The polarizers have been manufactured using graphite and GaIn24.5 deployed on ordinary materials used as substrates (paper and polymers such as PVA and PVC). Through a collaboration undertaken with the Chinese research group led by Professor Liu at Tsinghua University, alternative manufacturing processes were researched. All components were simulated through a commercial simulator based on the FIT finite integrals technique (CST Microwave Studio). Secondly, the potential of the fixed delay technique was investigated for rapid sensing of homogeneous and transparent items with possible application to industrial quality inspection. In this scheme, the current variation of the THz beam at a specific point is related to the variation of its optical parameters, thus it was demonstrated the ability of the method in detecting voids as well as in roughly estimating their volumes under certain conditions. Finally, a different approach for beam profiling based on a dielectric slit aperture was evaluated, as an alternative to the conventional methods used in the THz region and optics All measurements, both spectroscopy and polarization control, were made by means of a TDS-THz fibre-based system, with photoconductive antennas (PCA), both for the generation and detection of THz.
[CA] En el present treball, s'investiguen alguns aspectes del paper dels materials dielèctrics quan interactuen amb ones de THz. El bandgap de THz, que cobreix les freqüències de 100 GHz a 30 THz, ha despertat un gran interés principalment a causa de la seua baixa energia i la seua bona capacitat de penetració en alguns materials d'ús diari com els teixits i els plàstics. Les característiques peculiars de les ones de terahertz permeten la seua aplicació en diversos camps tecnològics, especialment com a eines científiques i per a la inspecció de control de qualitat. Per a avançar en l'aplicació pràctica de la radiació THz, la present tesi doctoral investiga diversos camins. En primer lloc, es s'han tractat mètodes alternatius de baix cost per a la fabricació de components passius de THz, centrant-se principalment en polaritzadors de THz. L'interés en el control de la polarització es deriva de la demanda d'un major control sobre les característiques físiques dels feixos de THz. Així mateix, s'han investigat els polaritzadors amb reixes de filferro flexible basats en l'efecte d'absorció dicroica. Els polaritzadors s'han fabricat utilitzant grafit i GaIn24,5 desplegats en materials ordinaris utilitzats com a substrats (paper i polímers com el PVA i el PVC). Mitjançant una col·laboració empresa amb el grup d'investigació xinés dirigit pel professor Liu de la Universitat de Tsinghua, es van investigar processos de fabricació alternatius. Tots els components es van simular mitjançant un simulador comercial basat en la tècnica d'integrals finites FIT (CST Microwave Studio). En segon lloc, s'ha investigat el potencial de la tècnica de retard fix per a la detecció ràpida d'elements homogenis i transparents amb possible aplicació a la inspecció de qualitat industrial. En aquest esquema, la variació actual del feix de THz en un punt específic està relacionada amb la variació dels seus paràmetres òptics, per la qual cosa es va demostrar la capacitat del mètode per a detectar els buits així com en l'estimació aproximada dels seus volums sota certes condicions. Finalment, un enfocament diferent per al perfil de feix basat en una obertura d'escletxa dielèctrica ha sigut avaluada, com a alternativa als mètodes convencionals utilitzats a la regió de THz i l'òptica.Tots els mesuraments, tant l'espectroscòpia com el control de la polarització, es van fer per mitjà d'un sistema basat en fibra TDS-THz, amb antenes fotoconductores (PCA), tant per a la generació com per a la detecció de THz.
Colleoni, MPM. (2020). Dielectric-based Components and Methods for Terahertz Sensing [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/149569
TESIS

Due to high demand for planar structures with low loss, a considerable amount of research has been done to the design of substrate integrated waveguide (SIW) components in the mm-wave and microwave range. SIW has many advantages in comparison to conventional waveguides and microstrip lines, such as compact and planar structure, ease of fabrication, low radiation loss, high power handling ability and low cost which makes it a very promising technology for current and future systems operating in K-band and above. Therefore, all the work presented in this dissertation focuses on SIW technology. Five di erent antenna systems are proposed to verify the advantages of using SIW technology. First, a novel K-band end- re SIW circularly polarized (CP) antenna system on a single layer printed-circuit board is proposed. A high gain SIW H-plane horn and a Vivaldi antenna are developed to produce two orthogonal polarizations in the plane of the substrate. CP antennas have become very popular because of their unique characteristics and their applications in satellites, radars and wireless communications. Second, a K-band front-end system for tracking applications is presented. The circuit comprises an antenna array of two Vivaldi antennas, a frequency-selective power combiner, and two frequency-selective SIW crossovers, which eliminate the need for subsequent ltering. The integration of monopulse systems in planar, printed circuit SIW technology combined with the added bene ts of ltering functions is of great importance to the antennas and propagation community. Third, a phased array antenna system consisting of 24 radiating element is designed as feed system for reflector antennas in radio astronomy applications. A Ku-band antipodal dipole antenna with wide bandwidth, low cross-polarization and wide beamwidth is suggested as the radiating element. Forth, four di erent right-angled power dividers including in-phase and out-of-phase dividers as feed systems for antenna arrays are introduced. TE10 - to - TEq0 mode transducers are used for obtaining two, three, and four output dividers with phase control ability at K- and Ka-band. This feature is practical, for instance, when designing tracking systems since they are employed to obtain controllable phase distributions over the output ports. Fifth, a Ku-band beam steering antenna system which is applicable to use for wireless communications, radar systems, and also 5G applications is proposed. This antenna system uses variable reflection-type phase shifters which electrically steer the beam over a 50-degree scan range. Therefore, the SIW technology's reliability and also promising behavior in the microwave frequency range is proven for di erent applications.
Graduate