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Suppression of side lobes of an antenna array by unequal power distribution on the elements
Saloka, Samuel ; Mikulášek, Tomáš (referee) ; Špůrek, Jan (advisor)
This bachelor thesis is focused on the design of an antenna array with four patch antennas. In the first part, the theory of a microstrip antenna and power divider with equal and unequal power distribution on elements design are summarized. In the second part, calculations necessary for the design of the antenna and both arrays are found. The third part contains modeling, optimizations and simulation results of the individual models and consequently the assessment of the results. A summarization of the measured results as well as photo documentation of the produced structures are in the fourth part. Conclusion of the entire work and its results are deliberated in last part.
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Antennas with metamaterial radomes
Martínek, Luděk ; Tkadlec, Roman (referee) ; Pítra, Kamil (advisor)
This thesis deals with microstrip antennas covered by the metamaterials. First, are described planar antennas, their problems and the emergence of surface waves. Surface waves can cause unwanted coupling among particular parts of the structure and can degrade its parameters. The problem can be solved using an electromagnetic band gap structure (EBG). These periodic structures are able to suppress surface waves in different frequency bands. It is shown how the EBG structure in the function superstate improve directivity and antenna gain. Radiation conventional microstrip antenna with metallo-dielectric EBG superstrate and with the purely dielectric double-layer superstrate is described. The both structures are designed and simulated in CST Microwave Studio program. Further is described the antenna radiation with so-called mushroom structure and metallo-dielectric EBG superstate. The structure is again designed and simulated in CST MWS program. Finally, there are two structures with metallo-dielectric superstate implemented and measured.
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Planar Antennas on Electromagnetic Bandgap Substrates
Horák, Jiří ; Dědková, Jarmila (referee) ; Škvor,, Zbyněk (referee) ; Raida, Zbyněk (advisor)
Planar antennas are used in several technical applications. The family of planar antennas contains microstrip antennas, which are very popular due to the low weight, low profile, simple manufacturing and easy mass production. Lower gain and excitation of surface waves are disadvantages of microstrip antennas. The propagation of surface waves can be efficiently suppressed if the conventional substrate is replaced by an electromagnetic bandgap (EBG) substrate. Microstrip antennas on EBG substrates have been presented in an open literature for several years. Nevertheless, no published work is devoted to the design of EBG substrates, which can suppress surface waves at several frequencies those cannot be covered by a single bandgap. In order to reach optimum parameters of designed antennas, selected global optimization methods are applied (genetic algorithms, particle swarm optimization, ant colony optimization).
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Circularly polarized button antenna on frequency selective surface
Košík, Samuel ; Cupal, Miroslav (referee) ; Kuřátko, David (advisor)
This bachelor thesis is focused on circularly polarized button antenna on frequency selective surface for resonant frequency 5.5 GHz. The concept for this thesis is adopted from article [1]. This published version of the antenna was simulated to verify the validity of the antenna structure behaviour. Several optimalizations have been presented to achieve the best possible results. After all, fantom has been made, as well as the antenna, and used to demonstrate funcionality of the antenna near a human body tissue model. The whole structure with the resonant frequency 5.5 GHz and compact dimensions is primary designed for on-body communication. However, its potentiality is much wider.
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Antenna a LNA for multiband GNSS receiver
Ondráš, Michal ; Baran, Ondřej (referee) ; Záplata, Filip (advisor)
This project describesa microwave antenna for GNSS and low noise amplifier. Mikrostrip antenna is a modern type of antenna. This mikrostrip antenna is Dual – band antenna with circual polarization. The thesis describes how to make anantenna, what a circular polarization is, whata patch antenna is and what GNSS is. Low noise amplifier amplifies the antenna output signal.
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Square type fractal antenna
Roháček, Peter ; Všetula, Petr (referee) ; Hebelka, Vladimír (advisor)
The bachelor thesis deals with analysis of fundamental parameters of antennas and methods of fractal construction. Attention is turn on microstrip antennas, where are discussed the basic properties, the pros and cons, methods of construction, power options and a demonstration of the theoretical proposal. These supporting documents were used for the actual design and optimization of the square fractal antenna in CST Microwave Studio program, which was subsequently implemented.
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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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Wideband rectangular patch antenna
Teplý, Tomáš ; Puskely, Jan (referee) ; Láčík, Jaroslav (advisor)
This thesis focuses on the design microstrip antennas with a maximum bandwidth. First discussed are the standard types of supply of these antennas with main attention to the coaxial power supply (power probe) and L-probe. Furthermore, the properties of these types of power examined in the program CST Microwave Studio. The results obtained are used for the design of rectangular Patch Antenna with a maximum bandwidth. The proposed antenna is modeled in CST Microwave Studio program and then implemented. The result of this work is a microstrip antenna, the impedance bandwidth is 32,14%.
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Dual-port microstrip circularly-polarised antenna
Holek, Karel ; Horák, Jiří (referee) ; Lukeš, Zbyněk (advisor)
The thesis is focused at the design and the execution of a dual-port microstrip circularly-polarized antenna for the frequency of 2.4 GHz. The first part describes general knowledge about microstrip antennas, circularly-polarized, options of power supply, used medium etc. The second part of the thesis deals with the design and simulation of antennas with the use of software called CST Microwave Studio and Zeland IE3D. In the last part, confrontation of simulation and measurement results is provided.
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Modeling of planar antenna loaded with ring resonators
Šrajbr, Michal ; Kovács, Peter (referee) ; Láčík, Jaroslav (advisor)
This bachelor’s thesis is focused on the design of the dual-band printed dipol loaded with split ring resonators. The principal of this antenna is described in the first part. The main focus is on the design and tuning of the split ring resonators on the required working frequency in the CST Microwave Studio program. These results are used for designing dual-band printed dipol loaded with split ring resonators working at resonance frequencies of 1,8 a 2,4 GHz. The simulation of this antenna was performed in the IE3D program Zeland. The designed dual-frequency printed dipole has been manufactured and measured.
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