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Planar mono- and dipole antennas for on-body communication
Maro, Ivan ; Láčík, Jaroslav (referee) ; Raida, Zbyněk (advisor)
This bachelor’s thesis is focused on designing and simulating several types of monopole and dipole textile antennas, which will be used for ON-body communication in ISM 5.8 GHz frequency band. It also examines the possibility of using a reflector made of artificial magnetic conductor to achieve an overall improvement in antenna parameters. The antenna has been subjected to bending, to ensure proper functionality when placed on different parts of the body. For selected antennas, a specific absorption rate SAR was also simulated so that the antenna meets the required limits specified by the competent authorities. Subsequently, two antennas were chosen for prototype production, which were produced by silkscreen printing technique. The manufactured antennas were measured in an anechoic chamber and their results compared with simulations.
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Miniature antennas for mobile communications
Kounek, Milan ; Láčík, Jaroslav (referee) ; Pokorný, Michal (advisor)
This bachelor thesis deals with downsizing techniques of planar antennas, while keeping important parameter for usage in mobile communications. In software IE3D there was designed antenna, working in ISM 2,4GHz band, which was downsized by methods described in this thesis. A group of antennas was created, 2 antennas were chosen, produced and measured. Results of measuring were compared with simulation and differences were evaluated.
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Modeling of microwave structures based on SIIG
Teplý, Tomáš ; Horák, Jiří (referee) ; Láčík, Jaroslav (advisor)
Well-known dielectric image guide reach in millimeter-wave interesting results. Compared to a conventional types of lines and waveguides is characterised by low-through loss for frequencies approaching 100 GHz. This work is detail focused to basic characteristics and especially type of perforate highpermitivity substrate for obtain implemented waveguide to dielectric board (SIIG). The work also contains couple suggestions for various transitions from a commonly used lines and waveguides. Simulation results using finite element method is achieved attenuation values below 2 dB, which corresponds to a 2 cm length and include a waveguide itself with a pair of transitions. Finally, this work also designed the production method and SIIG applicatoin in practicle.
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3D printed microstrip patch antenna
Medek, Petr ; Vašina, Petr (referee) ; Láčík, Jaroslav (advisor)
The bachelor thesis deals with the issue of inhomogeneous substrates of microwave patch antennas. The aim of this work was to find such a distribution of the permittivity of the substrate of a linearly polarized patch antenna, which would be possible to achieve an extension of the impedance bandwidth to an antenna with the same effective permittivity. The investigated patch antenna has a square shape, is linearly polarized, and is powered by a coaxial power supply. Few types of permittivity distribution are presented and compared with an antenna with a substrate with an adequate effective permittivity. For each antenna, the dimensions of the patch are adjusted so that the antenna is designed at a medium frequency of 2.45 GHz. Furthermore, an antenna with a constant permitivity with patch dimensions is designed and the permittivity of the substrate is adjusted so that the required frequency is achieved. In the two investigated styles, we observe an extension of the impedance bandwidth to the antenna with adequate effective permittivity in the order of hundreths of percent, which was subsequently verified by manufacturing and measuring.
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Half-mode SIW filter.
Jackovič, Petr ; Láčík, Jaroslav (referee) ; Hubka, Patrik (advisor)
This bachelor’s thesis presents the design of a half mode substrate integrated waveguide band-pass filter by quarter wavelength resonators. This filter is design symestric with quarter resonators are coupled by impedance and admittance inverters. Simulated results shows the HMSIW filter is good performance of low insertion loss, hight quality factor and compact size. In numerical model is good agreement of bandwidth and transmission between simulation and measurement.
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Pulsed Electromagnetic Field Radiation from Slot Antennas
Štumpf, Martin ; Vandenbosch, Guy (referee) ; Škvor,, Zbyněk (referee) ; Láčík, Jaroslav (advisor)
Jednoduché dvojrozměrné anténní zářiče, které slouží jako stavební bloky anténních polí, jsou analyticky analyzovány v časové oblasti. Jako hlavní nástroj pro analýzu je použita Cagniard-DeHoopova metoda. Je ukázáno, že zvolený přístup umožňuje získat přesné vzorce v časové oblasti v uzavřeném tvaru, které jasně demonstrují vliv vstupních parametrů a objasňují fyzikální podstatu pulsního elektromagnetického vyzařování. Dané numerické výsledky ilustrují důležité aspekty pulsního elektromagnetického záření v rozličných konfiguracích problémů. Získané výsledky jsou užitečné pro efektivní návrh anténních polí, které jsou buzeny pulsními signály.
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Half-mode substrate integrated waveguide horn antenna
Černý, Matěj ; Mikulášek, Tomáš (referee) ; Láčík, Jaroslav (advisor)
This thesis is about technology of half-mode substrate integrated waveguide (HMSIW) and options proposal of horn antenna fouden on this technology. Based on gained findings HMSIW horn antenna was modeled in program CST Microwave Studio. Main attention is focused on impact geometrical parameters of antenna on it´s emitting and on reflecting ratio at the entrance of antenna. Achieved gain of main lobe was 6 dBi, which is misalignmented to required direction of angle 30°. Antenna has a working frequency 10 GHz.
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Automotive antenna for mobile communications
Porč, Jan ; Láčík, Jaroslav (referee) ; Pokorný, Michal (advisor)
This thesis deals with design of flush–mounted planar disc antenna suitable for use in vehicles. For each of the bands GSM900 and GSM1800, which are used in Czech republic, an independent antenna has been created. As a simulator of the electromagnetic field the program IE3D has been used. For the improvement of theoretical results an optimisation in the program MATLAB has been developed. As the optimisation method the genetic algorithms have been selected.
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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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