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Numerical Modeling of Periodical Structures
Nešpor, Dušan ; Bartušek, Karel (referee) ; Brančík, Lubomír (referee) ; Fiala, Pavel (advisor)
The thesis discusses the dynamic electromagnetic field on periodic structures. The author focuses on three principal types of resonant structures, considering their application possibilities. In general, these types can be individually defined as follows: materials exhibiting a negative refractive index of the incident electromagnetic wave; structures with gradual changes in impedance, characterised by their usability as reflectionless surfaces; and periodic structures able to conveniently shape the magnetic field distribution. Materials of the third group within the above-shown short list facilitate the fabrication of magnetoinductive lenses for nuclear magnetic resonance. The presented analysis of the properties of periodic resonant structures is mainly based on numerical models utilising the finite element method, and this approach is combined with both the derivation of the corresponding analytical relations and an experimental measurement of the non-radiating component of the electromagnetic field. The thesis includes a physical description of the basic elements of periodic resonant structures. Physical properties of the elements were examined in detail via numerical analysis. In the course of the research, the data acquired through this analysis and the related experimental measurement enabled the author to propose a method for optimising the most widely used resonant structures. Moreover, several new versions of resonant elements, structures, and fabrication techniques were also designed. The results obtained from the numerical analyses carried out to examine the central physical properties of the fabricated structure samples were all verified via the designed method for measuring the non-radiating component of the magnetic field.
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Dual band power divider for GSM(900/1800)
Elfmark, Zdeněk ; Fiala, Pavel (referee) ; Šporik, Vladimír (advisor)
he work deals with different types of Wilkinson Power Divider suitable for band GSM (900/1800). In the thesis is talking about three types and contains the brief descriptions of their functions. It is mentioned their connection and the most important components of each types. All dividers are presented by form of simulation. The aim of this thesis is design and realizes a dual band Wilkinson Power Divider, using planar or SMD technology.
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Numerical modelling and measurement of the magnetic susceptibility in inhomogeneous materials by the NMR technics
Julínek, Michal ; Steinbauer, Miloslav (referee) ; Fiala, Pavel (advisor)
This bachelor work is concerned in magnetic susceptibility of specific object (glass cube filled with clay, with glass sphere in the centre). In the first part determining of magnetic susceptibility of object was carried out. Measuring was conducted on tomograph of ÚPT AV ČR. Method of gradient echo, which allows magnetic susceptibility determining of non-magnetic materials, was used. Distribution of magnetic field within the object was acquired (object was measured with and without sphere), the change of magnetic field (between object with and without sphere) was subsequently determined. In the second part, magnetic field simulation of the same object in the ANSYS software was performed. Calculation was conducted on 3D model by the finite element analysis. Distribution of magnetic field of object was acquired as a result of simulation. Results from simulation were compared with experimental findings.
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Study of the influence of magnetic fields on biological tissue
Vlachová Hutová, Eliška ; Fiala, Pavel (referee) ; Bartušek, Karel (advisor)
The aim of this research is to explore the influence of magnetic field on early somatic embryos (ESEs) of spruce and pine. The magnetic field is gradual. This is important for the experiment, each cluster of ESE was exposed to magnetic field of different intensity. The resulting report of this experiment consists of the comparison between various methods of image analysis and the difference in growth of ESEs due to different exposure to magnetic field and surrounding temperature. Enclosed is a proposal of ESE size computing algorithm from a given image.
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Model of the reactor chamber for microwave heating
Kříž, Tomáš ; Fiala, Pavel (referee) ; Kroutilová, Eva (advisor)
The diploma thesis deals with the concept of a high-frequency chamber which serves for desiccation of emulsion consisted of oil and water where the contents of water is over 30% of the emulsion capacity. The high-frequency chamber works on frequency 2,45 GHz. The task was to design a numerical model in which a high-frequency thermic conjugated problem is solved. The design of a high-frequency chamber is made up considering the heat distribution in inhomogeneous environment as well as chemical and physical changes. The proportions of the high-frequency chamber can guarantee the biggest output transmitted from the source to the chamber with the emulsion desiccated and uniform layout of electromagnetic field. These criteria are necessary for smooth heating of the emulsion desiccated. In this diploma thesis, there were several numerical models with various proportions made up. Finally, the one with the shortest time of heating the emulsion in reference to emulsion capacity was chosen.
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Self-adhesive antennas for on-body communication
Punar, Jan ; Fiala, Pavel (referee) ; Raida, Zbyněk (advisor)
This project is focused on planar antennas for on body communication. Project follows the concept of a self-adhesive antenna, which was published in [1]. The included report contains simulation results of the designed antenna, and compares them with results given in [1]. It describes the redesign of the antenna to the operation frequency 5.8 GHz for substrate Arlon 25N followed by subsequent conversion to the thin substrate FR4. The thesis also deals with antennas not only for on body communication but also for communication between the human body and the remote unit. Finally, the work contains measurement results of the reference antenna on the Arlon 25N substrate.
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Numerical modeling of free ions movement
Sukup, Luboš ; Steinbauer, Miloslav (referee) ; Fiala, Pavel (advisor)
This work deals of movement free ions in environment, which is affected by acting of electric field, magnetic field and their interacting. In first part is work focused on numerical methods, which solve exemplars situations. Here is important to properly choose adequate numerical method. Second part of this work interprets influence of these fields on the ions and influence of environment on final motion. The last experimental part is focused on model of cylindrical capacitor as a sensor, which models nonuniform electric field.
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Workplace for final testing of electronic transformers
Brýdl, Ondřej ; Fiala, Pavel (referee) ; Klusáček, Stanislav (advisor)
This article describes a complex suggestion for automatic tester machine for final testing of electronic transformers. There is also described universal device for measuring all types of transformers which are produced by ABB company. The main parameters of testing process are price, speed of measuring and high-quality measuring. The suggestion of the machine is optimized according to those parameters.
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Holographic records
Žáčik, Michal ; Drexler, Petr (referee) ; Fiala, Pavel (advisor)
Holographic records are relatively new technology. Their application is very wide. They apply in engineering, geology, medicine, communication technologies and in security services. This document discuss about short history of holography, basic principles and properities of used waves. Single types of hologprahy are divided by frequency (wavelength) of used wave. This work addicts to requirements of material properities that are applicable for recording and describes some of materials used for recording. There is also illustrated the basic principle of reconstruction of hologram. There is intended a method of recording hologram for MHz frequencies and also a suitable recording material.
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