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Antenna array to determine positions of airplanes
Zelenka, Pavel ; Pokorný, Michal (referee) ; Raida, Zbyněk (advisor)
The project is aimed to design an antenna array for an aircraft positioning system at an airport. The system operates at frequencies 1030 MHz and 1090 MHz. The antenna is also used by the DME/TACAN system operating in frequency range from 1025 MHz to 1150 MHz. The required impedance bandwidth of the antenna array is 125 MHz, i.ee from 1025 MHz to 1150 MHz. The theoretical part of the thesis analyses properties of different patch antennas and discusses the possibility of extending the impedance bandwidth. The practical part is focused on the development of the numerical model of the broadband stacked patch antennas. In addition, properties of the 3-element and 4-element antenna array are compared. At the end, results of the thesis are summarized.
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Modeling of Microwave Semiconductor Structures
Pokorný, Michal ; Mazánek, Miloš (referee) ; Voves, Jan (referee) ; Raida, Zbyněk (advisor)
Tato dizertační práce se zabývá modelováním mikrovlnných polovodičových struktur. Stále vyšší pracovní kmitočty komunikačních systémů zvyšují nároky na aktivní prvky a přenosová vedení, realizované zpravidla v monolitické integrované podobě. Přenosová vedení s rozprostřeným zesílením představují perspektivní řešení nejen jako zesilovací prvky, ale také jako aktivní napáječe mikrovlnných antén. V součastné době neexistuje vhodný softwarový nástroj pro jejich efektivní simulaci a návrh. První část této práce je zaměřena na implementaci termodynamické formulace modelu driftu a difuze pro numerickou simulaci transportních procesů polovodičových struktur v komerčním programu COMSOL Multiphysics. Další část je věnována implementaci Gunnova jevu v makroskopické aproximaci a vypracování simulační procedury pro analýzu struktur využívajících tento jev. Poslední část je věnována návrhu a analýze aktivních přenosových vedení a zlepšení jejich vlastností.
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Retrodirective antenna array
Šindler, Pavel ; Morávek, Ondřej (referee) ; Pokorný, Michal (advisor)
In the first part of this thesis a basic theory of retrodirective antenna arrays and their particular parts – antennas and mixers is summarized. Further, there is a basic summary of possibilities for an usage of retrodirective antenna arrays for an information transmission. The second part deals with the concrete retrodirective antenna array design. The design starts with creation of an antenna array model for MATLAB software. Then a suitable structure for further design is chosen. Further, particular parts of retrodirctive antenna array – a patch antenna, a mixer, a low-pass filter, a bandstop filter, a signal combiner and a Wilkinson power divider are designed and analyzed in Ansoft Designer software. For the patch antenna analysis also CST Microwave Studio software is used. The following part deals with the realization of particular parts of the retrodirecive antenna array and its parameters measuring.
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Holographic antenna
Klečka, Tomáš ; Polívka,, Milan (referee) ; Pokorný, Michal (advisor)
This master’s thesis deals with principle of microwave holography, methods of microwave hologram recording and analyzes some types of holographic antennas from structural and functional point of view. It also includes simulations of selected holographic antennas and their modi?cations, applies optimization on three types of antennas. Finally it reviews measured results of three costructed antennas.
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Planar and wired Yagi-Uda antennas
Křepela, Pavel ; Pokorný, Michal (referee) ; Mikulášek, Tomáš (advisor)
This work deals with the study of Yagi-Uda antennas, followed by analysis and design of planar antenna with wired reflector. The first part focused on the analysis of the antenna and parameters. Another part of the continuing investigation of the optimum parameters for a given antenna followed by a design in Wi-Fi 5 GHz band. The antenna is simulated in CST Microwave Studio. The final part devoted the results achieved
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Smith Chart Visualization Tool
Marek, Martin ; Pokorný, Michal (referee) ; Kadlec, Petr (advisor)
The objective of my bachelor thesis was to create a Smith chart visualization tool in computing environment MATLAB. I created an impedance Smith chart in graphical user interface which delineate parameters of basic line types. Parameters of transmission lines can be defined in the Smith chart as normalized impedance, reflection coefficient, normalized admittance or impedance in combination with line’s characteristic impedance. It is also possible to design simple matching circuits, e.g. with quarter-wave transformer, series stub, parallel stub or matching circuits with lumped elements.
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Technical calculation of linear antenna arrays
Halm, Martin ; Puskely, Jan (referee) ; Pokorný, Michal (advisor)
This project deals with methods of calculation of radiation patterns and input impedances of antenna arrays. The first part describes this issue at a theoretical level. After defining some fundamental parameters of antennas, there is an analysis of finite length dipole. It is followed by the theory of antenna arrays and means of input impedance calculation of antenna array elements. In the final part of the work, a program is designed on the basis of the theory. The program is MATLAB based and implements the above mentioned calculations.
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Dielectric directional coupler modeling
Šikl, Tomáš ; Čapek, Miloslav (referee) ; Pokorný, Michal (advisor)
Dielectric High-frequency transmission lines are natural alternative to the lines made of metal in term of low loss. These lines are mainly used in microwave techniques of measuring. The main object is to describe basic parameters of metal and dielectric transmission lines and their comparison. Next point is a basic overview of the excitation the lines from metal and it's application on dielectric transmission lines. Then make the simulation of microstrip directional couplers and coupler made by dielectric waveguides. The last point of work is construction these directional couplers and measuring their most important parameters.
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Beam steering antenna
Krejčíř, Dominik ; Pokorný, Michal (referee) ; Mikulášek, Tomáš (advisor)
The master s thesis deals with the design of the beamsteering antenna. Methods of the beamsteering and the final antenna design are described. This antenna operates in the ISM band with the central frequency of 5,8 GHz. The antenna is designed in the CST Studio Suite 2020. Butler matrix was designed as a feed network implemented as substrate integrated waveguide. An array of patch antennas was used for radiation.
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