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Near field of the dipole antennas
Beran, Vlastimil ; Tkadlec, Roman (referee) ; Nováček, Zdeněk (advisor)
The thesis describes the radiation of dipole antennas in near field area. More methods for evaluation of spatial dipole field arrangement are compared. The work target for practical use is to create software for simulation of near field values placed in planar or cylindrical observation plane. The computer programme is applicable to single dipole or dipole array. The limits for human body exposition of non-ionizing radiation are here implemented for compliance purpose in hygienic evaluations. The simulated results of field distribution are possible to display as graphs or save to data file. The results of own calculation are compared with results obtained by some commercial software as well by measurement of field components under model conditions.
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SIW-Based Circularly Polarized Antenna Arrays
Špůrek, Jan ; Joler,, Miroslav (referee) ; Mazánek, Miloš (referee) ; Raida, Zbyněk (advisor)
Tato disertační práce prezentuje nový koncept kruhově polarizovaných anténních řad na bázi vlnovodu integrovaného do substrátu. Hlavní devízou konceptu je modularita, kdy je základní stavební blok řady použitelný pro tvorbu komplexnějších řad a tento blok zároveň slouží jako šablona pro návrh komplexnější struktury. Anténní řada byla simulována a experimentálně ověřena pro frekvence 17 a 60 GHz. Na základě dosažených výsledků byla odvozena metodologie pro návrh a identifikovány klíčové oblasti návrhu. Následně práce představuje techniku zvýšení šířky pásma osového poměru kruhově polarizovaných anténních řad pomoci parazitních flíčků, které jsou umístěny nad zářiče v definované vzdálenosti. Anténní řada z první části práce byla použita v simulacích a experimentálním ověření pro frekvence 17 a 60 GHz, kdy byla tato řada rozšířena o parazitní strukturu, přidávajíc další vrstvu modularity do konceptu.
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Half Mode Substrate Integrated Waveguide Slot Antennas
Hubka, Patrik ; Schejbal, Vladimír (referee) ; Pánek,, David (referee) ; Láčík, Jaroslav (advisor)
This dissertation deals with the research of slot antennas based on a half-mode substrate-integrated waveguide (HMSIW). By using HMSIW, the physical size of the antenna is reduced by approximately half while maintaining excellent antenna performance. The thesis is consists of two factual parts. The first one (Chapter 4) proposes and describes linearly and circularly polarized HMSIW polarized U-slot antenna. The combination of these two antennas resulted in a polarization reconfigurable HMSIW slot antenna. The functionality of all these antennas are experimentally verified. These antennas achieve better performance compared to current developments of the similar HMSIW antennas. The functionality of the linearly and circularly polarized antenna are further investigated in deep by characteristic modal analysis and parametric procedure. Based on those investigations, design guides of those antennas are proposed. The second one (Chapter 5) deals with design and description of the simple circularly polarized HMSIW U-slot antenna array with linear organization of 1 × 4 basic radiators. The experimental verification proved that the antenna array with a simple feeding network achieved the competitive performance in comparison to the similar antenna array described in the literature.
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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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Reconfigurable slot antenna array
Weigel, Filip ; Pítra, Kamil (referee) ; Raida, Zbyněk (advisor)
This master's thesis deals with the basic principles of slot antennas. Models of antennas were simulated in a selected electromagnetic simulator CST MICROWAVE STUDIO (CST MWS). There are several models of slot antennas which are optimized for communication in the car at a frequency 8 GHz.
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Patch antenna array for IFF band
Mička, Josef ; Pítra, Kamil (referee) ; Láčík, Jaroslav (advisor)
This master thesis deals with designing and implementing an antenna array for the IFF band. The design includes an antenna element simulation and a feeding network design for the antenna array. The antenna element is designed as broadband and has an SWR of less than 1.5 in each band. Two stacked patches are used to achieve the required bandwidth. The patches are fed through a slot. An asymmetric stripline line is used for the feeding network. The simulated antenna array shows good impedance matching and gain properties. The final part of the master thesis compares the measured results with the simulated results. Finally, an attempt is made to improve the SWR of the manufactured antenna array.
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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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Antenna array for Ku band
Prouza, Jakub ; Mikulášek, Tomáš (referee) ; Raida, Zbyněk (advisor)
This diploma thesis deals with the selection of antenna elements suitable for use in an ultra-wide band antenna array for radar applications. The selection is followed by the design and measurement of a prototype. The realized gain of the whole structure, the main beam width and the possibility of electronic beamforming in the horizontal plane are the most important parameters of the designed antenna array. The numerical model of the selected antenna element was developed, and parameters were verified to exploit the element in the antenna array. Afterwards, the array was created as a numerical model. Results produced by simulations were verified by measuring the prototype subsequently.
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Slot Antenna Array Based on Substrate Integrated Waveguide
Sedláček, Petr ; Polívka, Milan (referee) ; Mikulášek, Tomáš (advisor)
The Master’s Thesis deals with the design of slot antenna array based on the substrate integrated waveguide (SIW). Various supply methods are described and the design procedure is approached. The antenna array was designed for Wi-Fi band of 5 GHz in the Ansoft HFSS simulation software. The optimalized parameters are impedance bandwidth (low reflection coefficient at antenna input in the desired frequency band) and the gain (the maximum value). As the result of the work 3 antenna arrays based on the substrate integrated waveguide are designed and fabricated: antenna arrays 2x1, 2x2 and antenna array 2x2 supplemented with housing for outdoor use. The work also contains a comparison of simulated and measured parameters of antennas.
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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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