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Waveguide-SIW transitions
Bednarský, Vojtěch ; Láčík, Jaroslav (referee) ; Špůrek, Jan (advisor)
This work deals with the design of waveguide transitions. In this work I describe two usually used types of waveguides and that is classical rectangular waveguide with standardized designation WR-10, which is designed for working frequency 94GHz. The second type will be a waveguide integrated into the substrate called SIW. In the first part, numerical models of waveguides are calculated and transitions are created. Numerical models are simulated in CST Microwave Studio. Transitions are constructed in two types. Horizontal transition and orthogonal transition. The results of the first part are obtained dimensions of parameters from numerical models and S-parameters of transition sets.
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Sensing signals of a sensor in digestive tract
Raška, Marek ; Láčík, Jaroslav (referee) ; Raida, Zbyněk (advisor)
Wireless capsule endoscopy (WCE) is a system for capturing images of human digestive tract for medical purposes. The antenna is one of the most important parts of the system. In this report, I present a solution for a system operating in the 2.4 GHz and 915 MHz ISM band. The capsule transmitter contains a conformal loop antenna placed on its outer wall. The planar monopole with a partial ground is used as a receiver. The systems have been verified by numerical simulations with a phantom representing digestive tract. The transmitting modules have the bandwidth of several GHz according to simulations. This allows the antenna to tolerate various effects of living tissues. The receiving antennas have the bandwidth of hundreds of MHz. The path loss of the radio link between antennas operating in 2,4 GHz band is lower than 94 dB for any capsule orientation and location. This does not ensure a sufficient signal strength at the receiving antenna. In contrast, the system operating at 915 MHz ensures sufficient signal level at the receiver.
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3D printed directional antenna
Dvořák, Václav ; Horák, Jiří (referee) ; Láčík, Jaroslav (advisor)
This master thesis deals with a study of directional antennas, followed by their design and optimization of horn antenna based on SIW for Ka band (26,5- 40 GHz). The first part of the thesis contains the theoretical analysis of the different types of directional antennas, also the SIW technology is described here. It also describes the 3D printing technology by means of which the final antenna should be made. The next part of this work is about design of horn antenna based on SIW. Simulation and optimization of the antenna will be done using the CST Microwave Studio. The horn antenna was modeled with three different dielectric loads. The horn antenna with an experimental triangular dielectric load was chosen for fabrication. The fabricated antenna has reached almost the whole bandwidth to cover Ka. The antenna gain was 9,38 dBi for 33 GHz frequency.
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Network for high-frequency on-body communication
Halas, David ; Láčík, Jaroslav (referee) ; Kokolia, Martin (advisor)
This work focuses on the design of a network for high-frequency communication on the human body. The thesis is focused on the design of two-band antennas, namely 2.4 GHz and 5.8 GHz. The antenna is integrated into the textile and works close to the human body. The introduction describes the problem of spreading electromagnetic waves along the human body. Further, the thesis deals with the applicability of different types of antennas for integration on the textile substrate. Based on the simulations performed, a suitable antenna is selected for the purpose. The simulation program used is the CST Microwave Studio. In the end, the antennas were optimized, subsequently manufactured and their parameters measured.
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Antenna for smart watch
Hájek, Miroslav ; Láčík, Jaroslav (referee) ; Cupal, Miroslav (advisor)
The objective of this work is a create a smart watch antenna, that will operate in two frequency bands. These are GSM (1.8 GHz) and ISM (2.4 GHz) bands. This antenna must be able to work when be placed on an elastic material that is used as a smart watch belt. Antennas options are analyzed and their suitability for given use. There is also an antenna model in CST microwave studio, where all the simulations were made. The antenna is also simulated on human hand models that have different dimensions and tissue ratios.
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3D printed directional antenna
Dvořák, Václav ; Horák, Jiří (referee) ; Láčík, Jaroslav (advisor)
This master thesis deals with a study of directional antennas, followed by their design and optimalization of horn antenna based on SIW for Ka band (26,5- 40 GHz). The first part of the thesis contains the theoretical analysis of the different types of directional antennas, also the SIW technology is described here. It also describes the 3D printing technology by means of which the final antenna should be made. The next part of this work is about design of horn antenna based on SIW. Simulation and optimization of the antenna will be done using the CST Microwave Studio. The final part of the thesis deals with evaluation of achieved results.
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Waveguide slot antenna for 10.5 GHz band integrated into the textile substrate
Sekanina, Jiří ; Láčík, Jaroslav (referee) ; Kokolia, Martin (advisor)
Bachelor thesis deals with the design of waveguide slot antenna for the 10,5 GHz frequency integrated in the textile substrate. The first part contains a general theory of transmission lines. The second part describes the design of a waveguide slot antenna. The third part contains procedures for designing a SIW slot antenna and the fourth part describes the design of 3x2 antenna array that is integrated into 3,4 mm thick textile with relative permittivity r = 1,2 with greater main lobe width requirements and side lobe suppression. The last part summarizes the results.
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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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Periodic structure design for directivity enhancement of dielectric resonator antennas
Slavíček, Radek ; Horák, Jiří (referee) ; Láčík, Jaroslav (advisor)
The thesis deals with linearly polarized dielectric rectangular resonator antenna (DRA) operating in the basic mode TEy11 and higher order mode TEy131 at f0 = 10GHz surrounded by an electromagnetic band gap structure (EBG). The dielectric resonator antennas, the EBG structure were designed and a method of integration of both components was developed. The simulated results show a significant improvement of the radiation pattern in the E-plane radiation pattern (narrower main beam, lower level of side lobes, higher directivity) in comparison to a conventional DRA. This was verified by the TEy11 measurement.
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Directional antenna for 60 GHz frequency band
Kratochvíl, Jakub ; Pítra, Kamil (referee) ; Láčík, Jaroslav (advisor)
The aim of this diploma thesis is to study the possibilities and problems of low-profile antennas and subsequently to design a directional antenna with spherical reflector for millimeter wavelengths. The theoretical part deals with basic information about horn and reflector antennas, and about SIW technology. In addition, the thesis deals with the specific design and modeling of the antenna using CST Microwave Studio. The simulated design achieved a sufficient bandwidth to cover ISM (57 GHz to 64 GHz) with gain 13.6 dBi at 60 GHz frequency. On fabricated antenna, the antenna impedance ratios were worse and the target bandwidth was not reached. Antenna gain was 14.33 dBi at 60 GHz frequency.
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