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3D textile integrated monopole
Füll, David ; Kufa, Martin (referee) ; Cupal, Miroslav (advisor)
This thesis deals with the design of omnidirectional monopole antennas. Using the parabolic reflector and the directors, the directional characteristics of monopole antennas are modified. This directional antenna, together with the omnidirectional antenna, examines the effect of various materials, the emission characteristics and the input reflection factor, near the antennas. These antennas are made of 3D textile, measured in anechoic chamber and compared to the designed antennas. At the end of the thesis is the summary and evaluation of the result.
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Antennas integrated into the window of the car
Bílek, Ondřej ; Puskely, Jan (referee) ; Kufa, Martin (advisor)
The aim of this work is design and implementation of FM and DAB antenna for radio transmitting and antenna for GSM 900, GSM 1800 and 2.4 GHz WiFi which could be implemented into the rear window car. Selected problem is solved by using microstripe antennas placed on a substrate. The antennas were designed by full-wave software CST Microwave Studio 2013.
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Broadband linear antenna array for BAN applications
Gaja, Tomáš ; Kufa, Martin (referee) ; Puskely, Jan (advisor)
The work deals with the design and the practical realization of a single element of antenna arrays and with the simulation of all elements of antenna arrays for application in BAN. The main attention is focused on the shaping of radiation pattern with suppression of unwanted side lobes. Based on these principles the script was created in MATLAB environment which effectively analyses features of each desired antenna array. The next section of this work is focused on design of narrowband Patch antenna and broadband Vivaldi antenna in frequency band ISM 5.8 GHz and supply network for antenna arrays. Designed antenna arrays were verified in simulator of electromagnetic field CST including their function and features in proximity of human tissue. These simulations were experimentally made only for a single element of antenna arrays. The results from measured radiation pattern were analyzed in script as array about eight elements.
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Circularly polarized dielectric resonator antenna
Zechmeister, Jaroslav ; Kufa, Martin (referee) ; Mrnka, Michal (advisor)
This thesis discusses the design circularly polarized dielectric resonator antennas for ISM band 5,8 GHz. In this work are explained and compared different ways of resonator feeding. There are also discussed the possibility of generating a circular polarization from a aperture feeding. Two methods of generating circular polarization in dielectric resonator antennas are simulated in CST Microwave Studio. This methods are C-shaped slot and cross slot. For antenna with cross slot feeding is also simulated effect of the manufacturing process to characteristics proposed antenna. The antenna is made, measured and the results are compared with simulations.
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Numerical synthesis of filtering antennas
Kufa, Martin ; Mazánek, Miloš (referee) ; Masopust, Jiří (referee) ; Raida, Zbyněk (advisor)
Dizertační práce je zaměřena na kompletní metodiku návrhu tří a čtyř prvkových flíčkových anténních řad, které neobsahují žádné filtrující části a přesto se chovají jako filtrující antény (filtény). Návrhová metodika kombinuje přístup pro návrh filtrů s přístupem pro anténní řady a zahrnuje tvarování frekvenčních odezev činitele odrazu a normovaného realizovaného zisku. Směr hlavního laloku přes pracovní pásmo je kontrolován také. S cílem kontrolovat tvary uvedených charakteristik, nové gi koeficienty jsou představeny pro návrh filtrujících anténních řad. Návrhová metodika byla ověřena na tří a čtyř prvkové filtrující anténní řadě přes frekvenční pásmo od 4,8 GHz do 6,8 GHz, pro šířku pásma celé struktury od 7 % do 14 % a pro požadovanou úroveň činitele odrazu od –10 dB do –20 dB. Celá metodika byla podpořena výrobou a měřením šesti testovacích vzorků filtrujících anténních řad s rozdílnými konfiguracemi. Ve všech případech se simulované a naměřené výsledky dobře shodují.
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Tunable ARC frequency filter
Kufa, Martin ; Murina, Milan (referee) ; Sedláček, Jiří (advisor)
This bachelor thesis deals with ARC frequency tunable filters. The introductory chapter generally focuses on the basic terms of the frequency filters, such as the mathematical expression of the transfer function, types of selective filters, tolerant field, etc. The next section describes the actual higher-order ARC filters and cascade sequencing, especially ARC band reject and possibilities of its implementation. Following is a concrete realization of the ARC filter to band reject with suggestions for tuning the frequency components in the frequency range 10 kHz to 100 kHz and retuning quality factor. Finally, this work contains the printed circuit board (PCB) design of the ARC frequency analog and digital filter section for tuning F0 frequency and quality factor Q setting using digital potentiometers. Furthermore, it also outlines the flowchart of the program for digital control.
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Circularly polarized serial antenna array
Hurt, Martin ; Tkadlec, Roman (referee) ; Kufa, Martin (advisor)
This work focuses on the design circularly polarized serial antennas array operate in the ISM band (5.725 GHz to 5.875 GHz). Design of antennas is divided into three parts. In the first part is designed feeding system, followed by two types of circularly polarized antennas and at the last point, these components are integrated. Furthermore, these antennas are fabricated, measured their parameters and used for experimental verification of the influence of multipath transmission in-vehicle.
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Planar fractal filter on defected ground substrate
Kufa, Martin ; Hazdra, Pavel (referee) ; Raida, Zbyněk (advisor)
The diploma thesis is focused on the design of planar filters combining fractal layouts and defected ground substrates. The diploma thesis can be divided into three main parts. First, basic knowledge about fractals is presented (creation of Minkowski Island and Koch loop, e.g.). Then, the principle of defected ground structure is described, and a combination of fractal motives with a defected ground structure is briefly introduced. Properties of investigated structures are verified by CST Microwave Studio and Ansoft HFSS. Second, different defected ground structures under the 50 transmission line are designed, and conventional equivalent filters are created. Filters are simulated and compared. In final, the investigated filters are recalculated for the substrate Arlon 25N, simulated, manufactured, measured and confronted with a conventional filter on the defected ground substrate.
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