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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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Textile slot antenna
Špůrek, Jan ; Polívka,, Milan (referee) ; Raida, Zbyněk (advisor)
This diploma thesis is focused on design of various antenna structures, based on slot antennas, created in the wider wall of a rectangular-shaped waveguide. As the substrate, it is used a 3D textile material, while its properties are examined. They were designed structures, that operate with linear and circular polarization, and other related structures, that are used for feeding and power division. Structures are designed to operate at central frequency of 8 GHz and its vicinity.
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Artificial magnetic conductor for textile-integrated circularly polarized antenna
Ritter, John Richard ; Kadlec, Petr (referee) ; Raida, Zbyněk (advisor)
This thesis deals with a circularly polarized antenna using an artificial magnetic conductor (AMC). The concept for this antenna is adopted from [1]. The antenna structure was simulated in its original, published form to verify the validity of the results in [1]. The antenna structure was then modified for manufacturing on a textile substrate and for operation in the ISM 5,8 GHz frequency band. After the modification the antenna was manufactured. The antenna properties were subsequently measured to verify the simulated results. The antenna can be potentially used in wireless communication systems, such as wireless body area networks (WBAN).
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Circularly polarized SIW cavity-backed microstrip patch antenna
Procházka, Petr ; Láčík, Jaroslav (referee) ; Mikulášek, Tomáš (advisor)
This bachelor thesis deals with a circularly-polarized substrate-integrated-waveguide cavity-backed microstrip patch antenna. The first part dedicates basic theoretical knowledge of microstrip patch antennas such as patch shape, the possibility of its excitation etc. The following part describes the possibilities and adjustments of generating circularly-polarized wave from a microstrip patch antenna for generating circularly-polarized waves and general knowledge about the advantages and application of circularly-polarized wave. The next part deals with a step-by-step design of a proposed antenna. The last part present a comparison of simulated and measured results.
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Dualband Antenna for Global Navigation Satellite System
Mikulášek, Tomáš ; Lukeš, Zbyněk (referee) ; Láčík, Jaroslav (advisor)
This master’s thesis introduces to the reader with a modern antenna type the microstrip patch antennas. The most common types of microstrip antennas and their parameters and feeding methods are introduced in the theoretical section of this master’s thesis. This section deals with the circularly polarized microstrip antennas. Design of an active dual-band circularly polarized antenna for global navigation satellite application in the AWR Microwave Office is presented in the practical section. The proposed single-fed dual-band circularly polarized design is achieved using two stacked square microstrip patches. The antenna operates at the L1 + E1 and L5 + E5a frequency bands. Antenna preamplifier consists of a low-noise transistor and a dual-band band-pass filter. The thesis describes realization and measurement results of the dual-band antenna performance in the anechoic chamber. Measured results of the preamplifier performance are presented.
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Biconical dipole antenna with circular polarisation
Urbaník, Jaroslav ; Černý, Petr (referee) ; Raida, Zbyněk (advisor)
Tato diplomová práce se zabývá teoretickými poznatky a návrhem bikónické antény pracující v kmitočtovém rozsahu 4 až 8 GHz. V rámci práce jsou také popsány způsoby impedančního přizpůsobení a vybrané typy polarizátorů elektromagnetických vln a radioprůzračných krytů. Na základě teoretických poznatků je určena koncepce návrhu bikónické antény a vybrán vhodný polarizátor pro zajištění kruhové polarizace vyzařovaných elektromagnetických vln.
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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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Parabolic antenna feed for X band
Lecián, Petr ; Mazánek,, Miloš (referee) ; Kasal, Miroslav (advisor)
The work addresses the unusual proposal feed for parabolic antenna with circular polariza-tion signal. This is a modified waveguide feed, waveguide polarizer with a septum. Contemporary RHCP and LHCP wave occurs in several applications of microwave commu-nication and measurement system. From this point of view the septum polarizer can be useful. The septum polarizer is a four-port waveguide device. The square waveguide at one end con-stitutes two ports because it can support two orthogonal modes. A stepped septum divides the square waveguide into two standard rectangular waveguides sharing a common broad-wall. The size of the septum as well as two versions of the waveguides excitation were analyzed and are described in this paper. Ansoft HFSS is software for design and simulation of feed. This software can visualize not only the specified model feed, but also the course of electromagnetic field in feed and over time.
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Design of circular polarized antenna for 2.4 GHz
Hase, Michal ; Lukeš, Zbyněk (referee) ; Láčík, Jaroslav (advisor)
In this thesis, I introduce two types of circularly polarized rectangular microstrip antennas at 2.44 GHz. First type has direct fed and the second has two inputs for fed. In first case is used a stub to make the frequency with minimum return loss and equal to the frequency with minimum axial ratio. In second case is use the power splitter to divide the wave in to two lines with phase shift 90° for feeding the patch. In this thesis is described, how to get the best results of Axial Ratio.
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