|
|
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.
|
|
|
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.
|
|
|
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).
|
|
|
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.
|
|
|
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.
|
|
|
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.
|
|
|
Birefringence Influence on Polarization Changes and Frequency on Optical Fiber Sensors
Panascí, Marco ; Grenar, David (referee) ; Filka, Miloslav (advisor)
This bachelor thesis deals with birefringence influence on polarization changes and frequency on optical fiber sensors. The objective of the thesis is to design and implement a set of measurements that analyze these effects. The theoretical part deals with analyzing the polarization-maintaning fiber, the polarization of the light, and the sensory optical fibers, with some research. The practical part deals with design of the workplace, control measurement and sensor response at different temperatures. After the practical part there is a discussion over the measured values. It was found that this sensory optical fiber responds to a change in the ambient temperature of the optical fiber. The main result is that the wavelength varies with temperature.
|
|
|
Optical Fiber Output Power Temperature Sensor Measuring Optimization
Koláčková, Aneta ; Grenar, David (referee) ; Filka, Miloslav (advisor)
This bachelor thesis deals with the issue of measuring optic power on the output of single mode fiber, used like temperature sensor, using birefringent. Thesis describes the basic knowledge about measuring power, standards and function of optical power meters. It also deals with polarization and representation polarization states using the Poincare sphere. In the practical portion is measured optic power on the output of the temperature sensor with a photodiod and after that is verifed by a polarimeter. The aim of this thesis is miniaturization of ending device for measuring intensity of light, that means replacing expensive and large polarimeter by cheap and small photodiod.
|
|
|
Polarization properties of laser beam
Březina, Vojtěch ; Hudcová, Lucie (referee) ; Poliak, Juraj (advisor)
Bachelor thesis deals with polarization properties of optical beam and determination her polarization state by Stokes parameters. Further is studied the influence of environment on the polarization of wave. At the beginning of the thesis, fundamental terms which concern wave polarisation including description of polarisation device are defined. In conclusion of the thesis, experimental workplace for polarisation properties measurement using Poincare sphere and Stokes parameters is designed. The object of the experimental part were: measurement of the polarization wave, Mueller matrix measurement, verification function beam splitter and the creation of supportive programs in MATLAB. The results of the experimental findings were determined, allowing to improve measurement.
|
|
|
Properties of the perspective ferroelectric materials
Krejčí, Josef ; Frk, Martin (referee) ; Rozsívalová, Zdenka (advisor)
This thesis studies the properties and the applications of prospective ferroelectric materials which are used in electrical engineering and electronic industry. Further are physically explained and mathematically described the basic principles running in their structure. The practical part is aimed to build a workplace for measuring the components of the complex permittivity in the frequency and temperature area, controlled by the programmed measurement and service application using the Agilent VEE Pro 8.0 and MS Excel. The functionality of the workplace was verified on the selected material samples by measurement and evaluation of selected properties. For this issue was created electronic text, which can be used as a guide for laboratory exercises and it is an integral part of this work.
|
guest ::
