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Influence of filler particles size on parts of complex permittivity of composite
Mohyla, Petr ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
This project deals with calculation parts of complex permittivity varnish samples which is filled by ground mica with variety size of particles. Opening of this project deals with theory of dielectric and effects in dielectric. Following topic is theory of compounds and expressions in composite systems. In practical part of work is include method which was use to make varnish samples, their temperature stress and whole results of measurement. In the end of work is influence of filler particles each filler types to dielectric material and including coefficient which include size of filler particles to suitable mathematical expression.
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Effect of Light Polarization on Optical Fibre Links
Obručník, Ondřej ; Křivánek, Vítězslav (referee) ; Kyselák, Martin (advisor)
The bachelor thesis deals with the emergence of polarization mode dispersion, its mathematical expression and also the influence, which polarization mode dispersion has on the optical communication channel. First, the chapters birefringence in fibers and polarization debate its emergence and basic characteristics, then are introduced two possibilities of mathematical expression polarization mode dispersion namely in Stokes and Jones space, whence is more closely examine Jones space. End work adverts about dependencies wavelength and birefringence on differential group delay, also about using fibre Bragg gratings in optical fibres and fall of characteristics grating on differential group delay.
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Design of circular polarized antenna for 2.4 GHz
Hase, Michal ; Lukeš, Zbyněk (referee) ; Láčík, Jaroslav (advisor)
In this thesis, I introduce two types of circularly polarized rectangular microstrip antennas at 2.44 GHz. First type has direct fed and the second has two inputs for fed. In first case is used a stub to make the frequency with minimum return loss and equal to the frequency with minimum axial ratio. In second case is use the power splitter to divide the wave in to two lines with phase shift 90° for feeding the patch. In this thesis is described, how to get the best results of Axial Ratio.
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Behaviour of ferroelectrics in an electric field
Krejčí, Josef ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
The submitted thesis describes characteristics and use of ferroelectric materials which find their utilization in electrotechnical and electronics industry. The thesis is mainly aimed at their behaviour in the electrical field at various intensity and also focuses on their diagnostic methods. The method using an oscilloscope is selected as the most suitable and described here in more detail. Measuring laboratory workplace for detection of characteristics of ferroelectric materials in the electrical field has been innovated with available equipment and then its utility has been verified. Temperature and electric tension dependence of components of complex permittivity and electric condition of the material has been scaled using selected samples of ferroelectrics. A text in an electronic form has been integral part of the thesis. The text can be used as an instruction manual for laboratory trainings.
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Measurement of polarized lightparametrs measurement on the optical-fiber sensor output
Drábek, Jakub ; Čučka, Milan (referee) ; Filka, Miloslav (advisor)
This master's thesis deals with the analysis of the optical power measurement using an optical fiber sensor. The thesis contains the theoretical background to understand the origin of polarization and its representation in space using Poincaré’s sphere and Stokes vectors. There is also a part describing optical performance measurement and the preview of analog measurements from various researches. Practical part focuses on verification of changes of fiber sensor parameters at temperature change in its surroundings and this part includes also additional suggestions for various types of measurements and verification of the function of the photodiode as an optical power transducer. Most measurements are based on the comparison of results obtained with the polarimeter. The results were plotted and discussed.
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Electrical properties of modified oligobutadienes
Toulová, Jana ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
Bachelor thesis deals with the behavior of dielectric materials in an alternating electric field. To identify the properties of dielectric materials in the frequency domain method was employed dielectric relaxation spectroscopy. On several samples of modified oligobutadiénů were measured frequency dependent components of the complex permittivity in the temperature range of negative temperatures, the ambient temperature.
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Automated measurement of polarisation properties of an optical beam
Březina, Vojtěch ; Vlček, Čestmír (referee) ; Poliak, Juraj (advisor)
Diploma thesis deals with polarization properties of an optical beam and the determination of its polarization state by means of the proposed automatic measurement method. Furthermore the influence of an environment on the polarization state of the optical wave is studied. At the beginning of this thesis the fundamental terms with respect to the wave polarization including the description of the polarization devices are presented. In conclusion a method for an automated experimental workplace for the measurement of the polarization properties using Poincare sphere and Stokes parameters is designed and verified.
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Quality of Services in Optical Access Networks
Šifta, Radim ; Křepelka, Václav (referee) ; Vlček, Čestmír (referee) ; Filka, Miloslav (advisor)
The thesis focuses on the optical access networks and deals with the issue of transmission parameters of the physical layer, their negative impact on the quality of the services parameters and the possibilities of reducing their effect using the polarization multiplexing. The first and second chapter describe the theoretical background necessary for understanding the subsequent parts. The third chapter contains the practical part of the thesis. At first the optical routes in the Czech Republic in terms of polarization mode dispersion, which is together with insertion loss the main limiting parameter of high-speed optical networks, are evaluated. In the following part the measuring of the temperature changes effects on the polarization mode dispersion of the passive components and the effect of temperature changes to the polarization multiplexed signal are evaluated. To double the bandwidth and reduce the influence of polarization mode dispersion on the quality of services, the two simulation models of optical access networks using polarization multiplexing were carried out. These theoretical outputs were verified by the practical measurements in the laboratory and subsequently on the real optical route. Finally, a draft of the broadband optical access network based on wavelength and polarization multiplexing was designed based on obtained knowledge.
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Polarization State of the Optical Wave
Macháček, Ivan ; Křivák, Petr (referee) ; Wilfert, Otakar (advisor)
The aim if this bachelor thesis was simulating optical wave and determination her polarization state by Stokes parameters. Further was studied influence of environment on polarization wave. In introduction work were defined fundamental terms concerning wave polarization, further were short described used polarization devices. Main part of this work was matrix description of some measuring methods, susceptible determine polarization wave and polarization characteristics environment, emphasis was given on possibility usage Fourier analysis. In experimental part were used piece of knowledge from mathematical simulation. Subject experimental were: measurement parameters wave plates, polarization wave and Mueller matrixes of some environment. Measured values were compared with theoretic groundwork. Calculations and generation graph was solving by the help of function created in development system Matlab. From results of the experimental part were determined findings, susceptible improving accuracy of measurement.
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