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Design and Realization of Metamaterial
Kovaľová, Soňa ; Drexler, Petr (referee) ; Nešpor, Dušan (advisor)
The thesis discusses the design of periodic resonant structures, studying of their impact to surrounding electromagnetic field and realisation of magnetoinductive lens with potential application in nuclear magnetic resonance imaging. Frequency tuning of structure by variation of different parameters is described. The finite element method in Ansys HFSS was used to analyse the properties of designed structures.
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Electrical properties of anisotropic dielectric material
Příkazský, David ; Štumpf, Martin (referee) ; Vélim, Jan (advisor)
This work is focused on finding the dielectric properties of unknown material. Especially those we affect the behavior of electrical energy in the material, this feature describes parameter permittivity of material. In this work will be used multiple methods to determine values of permittivity. These measured values of different measurement methods will subsequently compared to each other. Then be discussed in the conclusion reached values and comparing used measurement methods.
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Monitoring properties of nanocomposites on base epoxy
Libra, Miroslav ; Rozsívalová, Zdenka (referee) ; Polsterová, Helena (advisor)
The present thesis deals with the study of nanotechnology in the field of composite materials (nanocomposites). Furthermore, the production, composition and electrical properties of these materials. Samples for the experiment are made of epoxy resin as matrix and titanium dioxide TiO2 as fillers with different benefits. Are the measurements the temperature dependence of permittivity, loss factor and internal resistivity.
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Minimizing errors in measuring ultra low currents
Maule, Radek ; Frk, Martin (referee) ; Rozsívalová, Zdenka (advisor)
This work describes the methodology of measuring ultra low currents of the order of 10-8-10-14 [A] and the errors that arise during the measurement. This work is focused on electrical conductivity of insulation materials and interfaces electrode - dielectric during charging and discharging of the sample which is located in the ideal workplace.
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Properties of aprotic electrolytes for lithium-ion accumulators
Staněk, Vladimír ; Máca, Josef (referee) ; Frk, Martin (advisor)
The present work deals with the properties of suitable electrolytes for lithium-ion batteries. The first part described in the current issue of electrolytes for lithium-ion batteries, types of solvents and their properties and methods of measurement properties. The second part is devoted to the measurement of the properties of solvents and electrolytes such as relative permittivity, density and viscosity. Measurement of relative permittivity was focused on the measurement of the solvent mixture with varying the percentage of the solvent. Viscosity and density were measured on a solvent with a lithium salt added (final electrolyte).
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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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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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Miniature antenna for mobile applications
Šmarda, Marek ; Švanda,, Milan (referee) ; Pokorný, Michal (advisor)
This work deals with the most famous constructions of planar antennas. The work analyses selected methods of connecting planar antennas' charging with the possibility of impedance adaptation. An important part of the work consists of description of techniques for increasing bandwidth and conversely techniques for reducing the dimensions which are important for the design of planar antennas for mobile devices. The antennas were designed by means of theoretical basis and their properties were examined in the electromagnetic field simulator. The selected antenna model was constructed and its parameters were measured experimentally. The matching circuit for the antenna to tune it to different resonant frequencies was designed and constructed.
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Complex permittivity measurement of materials at microwave frequencies
Polák, Radek ; Hertl, Ivo (referee) ; Láčík, Jaroslav (advisor)
This article describes some methods of measuring complex permitivity in milimeter – wave band, their characteristics, anvatages and disadvantages. Discused are here the reasons for their use in the construction of work place. On the basis these reasons is chosen the best method for practical measurement. That is cavity resonant method. Article contain description of designed measurement system. Whitch is verified by computer simulating of developed model in HFSS Ansoft. Text contain also result of simulations and execute computing of comlex permittivity and tangent loss. In Conclusion is desribed results of practical permittivity measure with realized measurement system.
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