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Characteristics features of luminescence radiation solar cells
Malý, Martin ; Šimonová, Lucie (referee) ; Stojan, Radek (advisor)
This thesis deals with characteristic features of luminiscence radiation solar cells during electroluminiscence. Electroluminescence is the process in which a substance begins to radiate electromagnetic radiation (luminiscence radiation) due to passing electrical current. Various defects in the structure of the photovoltaic cell can cause polarization of that radiation. The aim of this thesis is to measure some polycrystalline solar cells by electroluminescence. Selected solar cell is measured by electroluminescence extended by polarizing filter and afterward collected data are processed in MATLAB.
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Use of the plane of polarization of light propagation for high-speed optical fiber transmission
Šimák, Petr ; Münster, Petr (referee) ; Filka, Miloslav (advisor)
Thesis deals with the use of polarization planes in light propagation for high-speed optical fiber transport. It also deals with the issue of polarized light, its mathematical description using Stokes and Jones vectors and representation using the Poincare sphere. We explain how can light be polarized. It also describes the transmission of information via optical fiber and polarization mode dispersion. At the end of the thesis we describe a design of optical networks for the use of two polarization planes as separate transmission channels.
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Simulation of dielectric materials absorption characteristics
Bačkovský, Pavel ; Novák, Vítězslav (referee) ; Křivík, Petr (advisor)
This projects deal with dielectric materials. Characterize definition of dielectric and polarization of dielectric. Shows dielectric relaxation. Specified conception dielectric absorption and interpreted them with DC voltage charging condensator. However, this thesis be engaged in simulation of this process. Output is simulation program of dielectric absorption characteristics for two relaxation mechanism.
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Vertically polarized Yagi antenna with magnetic dipole
Weigel, Filip ; Pokorný, Michal (referee) ; Raida, Zbyněk (advisor)
This bachelor’s thesis deals with the principles of operation and simulation of planar Yagi antennas with a magnetic dipole. Simulation of electromagnetic field was performed in the simulator CST MICROWAVE STUDIO (CST MWS). The project compares results of simulations of several types of Yagi antennas. These antennas can be used for the communication along the living tissue (on-body communication).
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Reconfigurable slot antenna array
Weigel, Filip ; Pítra, Kamil (referee) ; Raida, Zbyněk (advisor)
This master's thesis deals with the basic principles of slot antennas. Models of antennas were simulated in a selected electromagnetic simulator CST MICROWAVE STUDIO (CST MWS). There are several models of slot antennas which are optimized for communication in the car at a frequency 8 GHz.
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Polarization sensitivity of the fibre optics grating sensors
Babieska, Lukáš ; Šifta, Radim (referee) ; Urban, František (advisor)
This diploma thesis deals with the effect of full-length fixation of optical fiber gratings on their polarization dependence. In addition, the effect of primary protection and parameters of optical fiber gratings on their intrinsic polarization dependence was also investigated. The theoretical part of the thesis briefly describes the historical development of optical fiber gratings, the types of optical fiber gratings used and also describes in detail the principles of polarization dependence of optical fiber gratings and the mechanisms of polarization dependence of optical fiber gratings. In the practical part of the thesis, suitable measurement methods for measuring the polarization dependence of optical fiber gratings are proposed. Furthermore, these methods are optimized and used for subsequent measurements of the effect of fixation on the polarization dependence of optical fiber gratings. Many different methods of fixation of the optical fiber gratings were then used to measure the effect of fixation, and the degree of polarization dependence of the optical fiber gratings was evaluated for each of the different fixation methods. The practical part of the thesis is concluded with a detailed summary of the results obtained.
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Structural and electrical properties of PVDF-CNT composite
Misiurev, Denis ; Dallaev, Rashid (referee) ; Sobola, Dinara (advisor)
Electrospininig se osvědčil jako jeden z nejpopulárnějších a nejrozšířenějších způsobů výroby vysoce kvalitních vláken s požadovanými parametry. Kvalita a morfologie vyráběných vláken závisí na mnoha parametrů, jako je vlhkost, dávka materiálu, aplikované napětí atd. Omezení keramických piezomateriálů (křehkost, toxicita vzorků obsahujících olovo, obtížnost přípravy složitých tvarů atd.) vynutila výzkum v oblasti piezoelektrických polymerů. Jedním z nich je polyvinylidenfluorid (PVDF). polyvinylidenfluorid může by být připraven v různých formách: tenké filmy, objemové vzorky, vlákna. PVDF vlákna přitahují největší pozornost díky vysoké flexibilitě, nízké hmotnosti, mechanické stabilitě a chemické inertnosti. Vlastnosti PVDF vláken lze zlepšit pomocí doplňujících materiálů: keramické částice, kovové nanočástice, Graphicitové materiály jako jsou oxid Graphicenu nebo uhlíkové nanotrubičky (CNT).
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Dielectric properties of liquid insulators
Jahn, Michal ; Starý, Jiří (referee) ; Špinka, Jiří (advisor)
This master‘s thesis deals with measurement of liquid dielectric materials (insulators). Above all, it is the different kinds of clean and drinking water, but also transformer oils. There was done theoretical information retrieval about the given topic in this project and on the basis of theory there were realized the relevant measurements of selected properties of liquid dielectric, such as permittivity, capacitance, loss number, conductivity, but also temperature dependence of these parameters. The measurements were realized with the help of product manufactured at the faculty FEKT VUT and with the help of measuring system AGILENT 16452A. The measured results were evaluated, graphically processed and compared.
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Luminescence Diagnostic of Photovoltaic Cells
Stojan, Radek ; Frantík, Ondřej (referee) ; Šály,, Vladimír (referee) ; Vaněk, Jiří (advisor)
Diagnostic of photovoltaic cells defects is one of the key step in production. This dissertation thesis deals about diagnosis of photovoltaic cells by radiative recombination of electron - hole pairs. This radiative recombination is known as luminescence. Diagnostic methods using this local light emission in infrared region have innovative potential. The method of electroluminescence is one of the most widely used luminescence methods whose modifications are applied across the industry, especially in semiconductors. The main area of this thesis research is focused on non-destructive analysis of radiated infrared radiation of monocrystalline and polycrystalline solar cells in various modifications of standard electroluminescence method. In this research there are used two types of CCD cameras are used as luminescent radiation detectors. Method of photon emission microscopy is used for magnification element. Local light emission inspection by microscopy should have benefit to qualitative evaluation of solar cells defects. Radiation emitted by the solar cell has a wave character. This fact brings the potential of using some of the characteristics of the waves. We are talking about the intensity and mainly about new characterization by polarization during the detection of defects in the solar cell surface. Innovation of the measuring workplace of the standard electroluminescence method to use polarization analysis is one of the goals of this dissertation thesis.
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Design of optical fiber temperature sensor for detection of defense perimeter
Zámečník, Ondřej ; Grenar, David (referee) ; Filka, Miloslav (advisor)
This diploma thesis deals with the issue of measuring the ambient temperature using a~single-mode optical fiber used as a temperature sensor. The thesis describes the basic knowledge about polarized light, its propagation in optical fiber and describes special fibers that preserve polarization. It also deals with the representation of polarization states on a Poincaré sphere and the use of Stokes and Jones vectors. In the practical part, several selected methods of optical signal supply to the temperature sensor are measured. Subsequently, the suitability of the given methods is evaluated from the measured results and the courses are compared with the records measured from real routes. This thesis aims to select a suitable connection of a temperature sensor for a long route of optical fiber and verify its functionality.
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