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Analysis of planar junction in millimeter bands
Ambros, Martin ; Oliva, Lukáš (referee) ; Lukeš, Zbyněk (advisor)
This diploma thesis solves possibilities of transitions between waveguides and hybrid types of integrated microwave circuits. It describes the basic ways of solutions this transitions in both longitudinal and transverse as well. In thesis is also mentioned the principle of SIW technology, which is in this transitions widely used. The practical part is focused on the modeling and analysis of selected structures in CST MW Studio. Modeled structures are optimized for the lowest possible value insertion loss transition and are adapted to the characteristic impedance on 50. Selected structures are recalculated to a lower frequency band, realized and results of their simulation verified by measurements.
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Transmitting antenna with dual circular polarisation for indoor antenna measurement range
Mrnka, Michal ; Hazdra, Pavel (referee) ; Raida, Zbyněk (advisor)
The purpose of the thesis is to design transmitting antenna based on septum polarizer solution for indoor measurement range. The antenna is considered for both senses of circular polarization. The design is divided into three main sections. First section is devoted to analysis and selection of a suitable waveguide. Ridge waveguide as a crucial part of a septum polarizer is mentioned in this section. Second part is the most critical; here the septum polarizer is analyzed and based on simple procedure also designed. Two suitable horn apertures are then developed as a part of the third section. Individual transmitting antenna parts are assembled together into one model and simulated with excellent results for axial ratio, cross-polarization discrimination, return loss and isolation between ports.
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Double ridge horn antenna for antenna measurement
Vašina, Petr ; Hertl, Ivo (referee) ; Láčík, Jaroslav (advisor)
The thesis deals with broadband antennas for measurement purposes. A ridged horn antenna has been selected for this concept, designed for the frequency range 0.9 GHz to 9 GHz. This work contains general theoretical description of antennas and further it focuses on a specific design of the ridged horn antenna, beginning with the calculation of its dimensions, modeling and optimization to obtain desired antenna properties. Finally, the antenna was constructed and measured. The reflection factor s11
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Computer modeling of a ridge horn antenna
Lacko, Tomáš ; Lukeš, Zbyněk (referee) ; Láčík, Jaroslav (advisor)
This project includes design and simulation of double ridge horn antenna with frequency range from 1,73 GHz to 14,94 GHz. This work is especially target to calculation proportion of horn for requested gain 20 dB and parameters of double ridge horn antenna. The main aim of project is design of antenna with her computer simulation. Antenna is created and simulated by program CST Microwave Studio.
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Ultrasound desintegrator of concrements
Straka, Petr ; Čížek, Martin (referee) ; Rozman, Jiří (advisor)
This thesis is focused on the methodes of crushing kidney’s concrements with continual wave for the frequency 27 kHz and the intensity of ultrasound 10 W/cm2. The main aim is design of the ultrasound head with layer converter and design circuitry. First part of this work describes physical principle of ultrasound, ultrasound waves and methods by which could be remove kidney’s concretions. Practical part of this work is focused on compreshive design of ultrasound crushing system. In the introdiction is analyzed the proposal of applicator and the next step decscribing proposal excitation generator. The work contains results of simulation which was done on proposal curcuit, drawings of scheme, list of components and drawing of PCB.
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Substrate integrated waveguide filter
Vyskočil, Jiří ; Tkadlec, Roman (referee) ; Láčík, Jaroslav (advisor)
In this thesis is discussed a filter design of a band-pass substrate integrated waveguide filter on the frequency of 5 GHz. It also includes design theory, filter synthesis, filter analysis in the program CST Microwave Studio® and the results of measurement on a vector network analyzer. The analysis results are compared with the measured results. Good agreement between simulated and measured results is observed.
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Time domain edge finite elements
Cigánek, Jan ; Motl, Milan (referee) ; Raida, Zbyněk (advisor)
Diplomová práce se zabývá metodou hybridních (hranových a uzlových) konečných prvků ve frekvenční i časové oblasti. Tato metoda je použita pro analýzu vlnovodu parallel-plate, v kterém jsou umístěny dvě dielektrické vrstvy. Jako ukončení vlnovodu je implementována dokonale přizpůsobená vrstva označována PML. Projekt řeší možný výběr PML vrstvy v časové oblasti. Metoda je programována v programu MATLAB a výsledky jsou porovnány s programem COMSOL Multiphysics.
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Design and realisation of microwave directional coupler
Nejedlý, Miroslav ; Motl, Milan (referee) ; Dvořák, Radek (advisor)
The diploma thesis deals with microwave directional coupler. The paper presents some of the microwave directional coupler and an analysis of bifurcations. The paper also discussed the various techniques of bifurcations and the bandwidth to which they are making. Proposal is implemented in two selected directional couplers and determining their size. They also performed using the selected simulation program selected two bifurcations. Furthermore, these couplers are made on the perimeter of the analyzer is verified by their actions and are verified by the actual parameters of the coupler.
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Modeling waveguides by time-domain finite elements
Fasora, Pavel ; Motl,, Milan (referee) ; Raida, Zbyněk (advisor)
The thesis deals with frequency domain finite elements and time domain finite elements. Derivation of the wave equation, generation of the discretization mesh and the composition of matrices for solving wave equation are presented. Exploitation of COMSOL Multiphysics for the analysis of the electromagnetic wave propagation in a wave guide is explained. Finally, in this thesis is described the m-file of MATLAB for analyzing electric field intensity of the waveguide in longitudinal direction to both domain. In last part is concisely exposed perfect match layers.
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Heating in lossy waveguide
Tichý, Jakub ; Horák, Jiří (referee) ; Raida, Zbyněk (advisor)
This thesis deals with modeling of a waveguide with the rectangular cross-section in Comsol Multiphysics and optimization with PSO algorithm in MATLAB. The practical section describes electromagnetic wave excitation at different frequencies; and the influence of changes of basic characteristics, proportions and the location of an inserted dielectric slide on passing electromagnetic wave in a single-mode band. In next phase of the project, changes of basic characteristics on heating structure at electromagnetic field excitation by this waveguides are discussed. The last part deals with optimizing waveguide filter with particle swarm optimization and research his new electric and thermal character. Modeled phenomena are illustrated by pictures of a waveguide from the axial upper projection, and on rectangular charts.
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