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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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A Brief Design of Optical Resonators
Hubík, Daniel ; Nešpor, Dušan (referee) ; Kadlec, Radim (advisor)
This bachelor thesis is focused on analysis of split-ring resonators in THz region. Simulations were made by finite elements method and by finite-difference time-domain method. At first we created a resonating structure that works in GHz region. Then we were observing a dependence of movement of resonant frequency on the size of resonator. In the final chapter we assigned frequency dependent values of permitivity to such structure. As the result we simulated working resonator at frequency 500THz. All simulations have been made in program HFSS ANSYS and Lumerical FDTD Solutions.
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Analysis of an Electromagnetic Wave on the Boundary between Electromagnetic Materials
Kadlec, Radim ; Lazar, Josef (referee) ; Macháč, Jan (referee) ; Kroutilová, Eva (advisor)
The proposed dissertation thesis contains an analysis of conditions on the boundary between layers having varied electromagnetic properties. The research is performed using consistent theoretical derivation of analytical formulas, and the underlying problem is considered also in view of multiple boundaries including the effect of the propagation of electromagnetic waves having different instantaneous speed. The author presents a survey and formulation of the basic characteristics of methods used for electromagnetic wave propagation analysis; in this respect, special emphasis is placed on radial models. The processing of the topic involved the designing and verification (using a set of different, layered planar materials) of algorithms to analyze the electromagnetic field components. The algorithm was assembled to enable simple evaluation of all components of the electromagnetic field in relation to the speed of the wave propagation in a heterogeneous environment. The proposed algorithms are compared by means of different numerical methods for the modelling of electromagnetic waves on the boundary between materials; moreover, electromagnetic field components in common points of the model were also subject to comparison. When in conjunction with tools facilitating the analysis of material response to the source of a continuous signal, the algorithms constitute a supplementary instrument for the design of a layered material. Such design enables the realization of, for example, recoilless plane, recoilless transition between different types of environment, and filters for both optical and radio frequencies.
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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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Physics of Metamaterials
Láska, Martin ; Kalousek, Radek (referee) ; Dub, Petr (advisor)
The bachelor work deals with electrodynamics of metamaterials for which both the electric permittivity and magnetic permeability are simultaneously negative. It is shown that the double negative media are described by a negative refraction index which has an important impact on optics laws. In particular, the negative refraction is demonstrated by simulation of interaction of the Gauss monochromatic beam impinging on a negative refractive material. Next, the electromagnetic energy propagation in the negative refractive materials is studied. It is shown that the energy propagation velocity equals the group velocity, which has the opposite sign than the phase velocity. Finally, Fresnel formulas valid both for positive and negative refraction index are given.
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