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Wideband low-profile circularly polarized antenna array
Benites Ayala, Jhony Cristian ; Cupal, Miroslav (referee) ; Raida, Zbyněk (advisor)
This bachelor’s thesis is focused on the study of a novel type of wideband low-profile circular array antenna with circular polarization and high gain. The aim of this thesis is to design, optimize and implement the proposed antenna for a 5.5 - 7 GHz frequency band. The thesis deals with theoretical fundamentals in order to subsequently present the concept of the antenna. Furthermore, it describes its design and implementation stages. The antenna was designed in the full-wave program CST Microwave Studio and fabricated on dielectric substrate. Both simulated and measured property results are evaluated in the conclusion.
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Computer modeling of implantable antennas
Deneš, Roman ; Kadlec, Petr (referee) ; Raida, Zbyněk (advisor)
The thesis deals with a design of planar antennas and their simulation in the vicinity of a human body. The main goal of this thesis is parametrically analyse different types of planar antennas and find out which one possesses the highest quality in the vicinity of a human body. The design and simulation were made in a software called CST Microwave Studio. Firstly, the attention is paid to the concept of designing and simulation. Further, they are made and tested.
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Antenna for in-car UWB communication
Špůrek, Jan ; Puskely, Jan (referee) ; Raida, Zbyněk (advisor)
This bachelor’s thesis is focused on the design of a wireless UWB network inside a car. The project is divided into three parts. In the first part, we describe the design of suitable antennas and feeding structures. The second part is focused on the simulation of a reciprocal communication for each type of the antenna in free space. In the third part, we investigate the effect of interference caused by near parts of the car for each type of the antenna. The results are then evaluated and the most suitable antenna is chosen for realization. The fourth part describes modifications of the antenna for SMA connector, which is necessary for measurement. In the fifth part we discuss measured results and compare them with assumptions from simulations. Results of the thesis are summarized in the conclusion.
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Artificial neural network for modeling electromagnetic fields in a car
Kostka, Filip ; Škvor, Zbyněk (referee) ; Raida, Zbyněk (advisor)
The project deals with artificial neural networks. After designing and debugging the test data set and the training sample set, we created a multilayer perceptron network in the Neural NetworkToolbox (NNT) of Matlab. When creating networks, we used different training algorithms and algorithms improving the generalization of the network. When creating a radial basis network, we did not use the NNT, but a specific source code in Matlab was written. Functionality of neural networks was tested on simple training and testing patterns. Realistic training data were obtained by the simulation of twelve monoconic antennas operating in the frequency range from 2 to 6 GHz. Antennas were located inside a mathematical model of Octavia II. Using CST simulations, electromagnetic fields in a car were obtained. Trained networks are described by regressive characteristics andthe mean square error of training. Algorithms improving generalization are applied on the created and trained networks. The performance of individual networks is mutually compared.
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Circularly polarized textile-integrated antenna array
Rujzl, Miroslav ; Láčík, Jaroslav (referee) ; Raida, Zbyněk (advisor)
This bachelor thesis deals with the design of the right-hand circularly polarized antenna arrays operated in the ISM band 5.8 GHz. The planar antenna array is integrated into the 3D textile produced by SINTEX, which is used as upholstery on the roof of a car. In the thesis, several antenna models are described. Models operate with linear and circular polarization. Initial antenna designs were based on a microstrip technology. Later antenna designs are modified using substrate integrated waveguide technology. Finally, a three-element patch array with a coaxial excitation was fabricated and tested.
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Numerical solutions of EMC problems of small airplanes
Šeděnka, Vladimír ; Dědková, Jarmila (referee) ; Mazánek, Miloš (referee) ; Raida, Zbyněk (advisor)
Disertace popisuje současné problémy v certifikaci malých letadel, které by se měly v budoucnu řešit numerickým modelováním. Tento postup má zefektivnit návrh a zlevnit certifikaci letadel. Práce je úzce spjata s projektem HIRF-SE, který se problematikou certifikace letadel numerickými metodami zabývá. Podstatná část práce je věnována popisu dvou modulů pro platformu HIRF-SE: řešič BUTFE založený na metodě konečných prvků v časové oblasti a budicí nástroj BUTFE_EXC. Práce popisuje řešení pohlcujících okrajových podmínek, modelování disperzních a anizotropních materiálů a aproximaci tenkých drátů. Speciální pozornost je věnována řešení aproximace tenkých drátů s ostrými ohyby, jejíž současná formulace způsobuje překryvy mezi jednotlivými segmenty drátu.
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Modeling metamaterial microwave resonators
Zvolenský, Tomáš ; Kovács, Peter (referee) ; Raida, Zbyněk (advisor)
Práce je věnována modelování mikrovlnných rezonátorů z metamateriálů (materiálů se záporným indexem lomu). V úvodu je rozebráno, co metamateriály jsou, jak se vytvářejí a které jejich vlastnosti jsou podstatné při návrhu rezonátorů. Následuje návrh planárního rezonátoru z metamateriálů. Pro tento účel byly naprogramovány funkce počítající rozměry jednotlivých součástí struktury. Simulace navržené struktury probíhala v programu Zeland IE3D. Simulované struktury byly optimalizovány s ohledem na požadované kmitočty rezonance. První rezonátor sestával z jedné elementární buňky, druhý ze dvou buněk, naladěných na rozdílné kmitočty. Rezonátory byly vyrobeny a experimentálně byly ověřeny jejich vlastnosti.
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Improving antenna parameters by the application of metamaterials
Šporik, Vladimír ; Hertl, Ivo (referee) ; Raida, Zbyněk (advisor)
The thesis is focused on the design of a planar resonant-type antenna, which exploits a proper combination of left- and right-handed properties of transmission lines. This transmission line is called CRLH TL and is based on Sievenpiper mushroom structure. Advantages of the proposed antenna concept are demonstrated by a detailed comparison of its basic properties with the properties of a conventional patch antenna.
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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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