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Modelování mikrovlnných struktur na bázi SIIG
Teplý, Tomáš ; Horák, Jiří (oponent) ; Láčík, Jaroslav (vedoucí práce)
Dobře známý dielektrický vlnovod se zemní deskou dosahuje v oblasti milimetrových vln zajímavých výsledků. Oproti běžným typům vedení a vlnovodů se vyznačuje především svým nízkým průchozím útlumem pro kmitočty blížící se 100 GHz. Tato práce se detailně zabývá jeho vlastnostmi a především typem úpravy vysokopermitivitního substrátu pro dosažení implementace vlnovodu do dielektrické desky (SIIG). Práce dále obsahuje i návrhy pro různé způsoby přechodu z běžně používaných vedení a vlnovodů. Za pomoci simulace, využívající metodu konečných prvků, je dosaženo hodnoty útlumu pod hranici 2 dB, která odpovídá délce vlnovodu 2 cm a obsahuje mimo samotného vlnovodu i dvojici přechodů. V neposlední řadě je v této práci navržen také způsob výroby a uplatnění SIIG vlnovodu v praxi.
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RF Impairments: Estimation Compensation and Exploitation
Pospíšil, Martin ; Viščor, Ivo (oponent) ; Galajda, Pavol (oponent) ; Maršálek, Roman (vedoucí práce)
This thesis deals with the hardware imperfections of wireless transceivers – dominantly with the measurement setups and techniques for their compensation, but also with their exploitation providing the additional physical layer security. The first part of the thesis consists of brief introduction to the domain of research, formulation of research questions, and introductory part providing brief discussion of wireless front-end impairments, low-complexity digital predistorters, or basic classifiers. The most important section of this part then contains description of the state-of-the art mm-wave experimental setups. The core of the dissertation is composed as a selection of eight published papers complemented with the selected additional information on the hardware or experiments carried on. Three of the papers have dealt with RF impairments exploitation for transmitter authentication, two other focus on the implementation of low-complexity digital predistorters for power amplifier nonlinearity, and remaining three describe our millimeter-wave testbeds together with the achieved results of digital impairment compensation in 60 GHz band.
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Millimeter Wave Band Wireless Channel Measurement Techniques in Automotive Applications
Vychodil, Josef ; Kovář, Pavel (oponent) ; Masopust, Jiří (oponent) ; Derbek, Vojtěch (vedoucí práce)
This doctoral thesis deals with the millimeter wave band wireless channel measurement techniques in automotive applications. After a brief introduction into the topic and the summary of the current channel measurement techniques, the goals --- the development and assembly of a measurement system, capable of capturing all of the millimeter wave band channel features and practical measurements with this system, are set. The next part is the core of the dissertation --- the developed channel sounder is presented and a detailed description of used methods, principles, hardware and data processing is given. A significant part of the thesis is dedicated to the mitigation of the unwanted effects caused by the non-linear components in the measurement chain. The last chapters show the results of practical measurements of various scenarios --- the intra-car channels, vehicle to vehicle channels as well as vehicle to infrastructure channels.
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Modelování propagace signálu bezdrátových sítí LTE a WiFi uvnitř budov
Olbert, Jaroslav ; Mašek, Pavel (oponent) ; Hošek, Jiří (vedoucí práce)
Diplomová práce se zabývá problematikou modelování propagace signálu bezdrátových sítí uvnitř budov. Teoretická část práce se věnuje principům a metodám šíření elektromagnetických vln ve venkovním prostředí i uvnitř budov. Dále jsou popsány metody výpočtů propagace signálu ray-launching a ray-tracing. V závěru první části je popsán algoritmus a vzorce, použité pro simulaci šíření signálu 5GHz WiFi uvnitř prostor UTKO. Druhá polovina práce obsahuje popis modulu mmWave, který byl využit pro simulace standardu 802.11ad (WiGig) a následně výsledky získané simulacemi v simulátoru NS-3, jejich rozbor a porovnání s výsledky získanými měřením v reálném prostředí.
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Trychtýřová anténa s potlačenými bočními laloky
Kaděra, Petr ; Puskely, Jan (oponent) ; Mikulášek, Tomáš (vedoucí práce)
Tato diplomová práce je zaměřena na způsoby možné realizace směrové trychtýřové antény s potlačenými bočními laloky v kmitočtových pásmech 71-76 GHz a 81-86 GHz. V práci je provedena rešerše možných metod řešení včetně srovnání jejich parametrů, zhodnocení kladů a záporů jednotlivých řešení. Mimo dané technické požadavky zadání byl kladen důraz také na výrobní možnosti a cenovou dostupnost materiálů použitelných pro danou anténu. Hlavní část práce je věnována kónické trychtýřové anténě zatížené hyperbolickou dielektrickou čočkou dále pak možnosti využití antény s plochou čočkou na bázi vysílacího pole a také antény s integrovanou eliptickou čočkou. Následující část práce se zabývá možnostmi charakterizace vlastností dielektrického materiálu čočky.
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Motionless Presence Detection of Humans
Szabó, Tomáš ; Dolejška, Daniel (oponent) ; Pluskal, Jan (vedoucí práce)
The goal of this thesis is to find generic solution for detecting a person in the smart home network. Simple implementation of the PIR sensor registers a person coming to a room, yet when the person becomes stationary by working on a laptop or watching a television it cannot detect him/her any further. Via a millimeter-wave radar it is possible to tell, if the person is still in the room or he/she left. The existing commercial solution tends to be rather expensive and in the most part of world unavailable for purchase. The solution can be implemented as an individual unit communicating with the development kit as a part of set of sensors. The testing takes a place at NES@FIT spaces, where the current solution is realized by PIR sensors.
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3D PRINTED ARTIFICIAL MATERIALS FOR MICROWAVE STRUCTURES
Kaděra, Petr ; Soh, Ping Jack (oponent) ; Polívka, Milan (oponent) ; Láčík, Jaroslav (vedoucí práce)
The dissertation thesis deals with the research of 3D printed artificial electromagnetic structures exploitable for antenna and microwave component design. Artificial structures containing dielectric and metallic inclusions of various geometries are investigated, and their precise description, including the anisotropy effect, can improve the actual design speed and accuracy. First, the models based on the analytical parallel plate capacitor method are compared with an effective medium theory, numerical, and experimental results, which are provided for various parameters of materials available in 3D printing technology. The proposed models derived by the parallel plate capacitor method can generally be exploited for faster and highly accurate determination of the effective complex permittivity, which enhances its potential to be used with optimization techniques. Second, the hybrid multimodal transfer matrix method is exploited as a general and effective way for calculations of the effective permittivity and effective permeability of artificial structures containing both dielectric and metallic inclusions through the volumetric space of the structures studied. The artificial structures containing metallic inclusions generally allow to achieve a wide tuning range of the effective constitutive parameters. Finally, suitable structures with spatial permittivity distribution are developed for wide-angle millimeter-wave gradient-index Luneburg lenses employable as antennas or retroreflectors for wide angular coverage and stable radar cross section enhancements of passive, chipless frequency-coded radiofrequency identification tag landmarks which have a large potential for indoor self-localization.
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RF Impairments: Estimation Compensation and Exploitation
Pospíšil, Martin ; Viščor, Ivo (oponent) ; Galajda, Pavol (oponent) ; Maršálek, Roman (vedoucí práce)
This thesis deals with the hardware imperfections of wireless transceivers – dominantly with the measurement setups and techniques for their compensation, but also with their exploitation providing the additional physical layer security. The first part of the thesis consists of brief introduction to the domain of research, formulation of research questions, and introductory part providing brief discussion of wireless front-end impairments, low-complexity digital predistorters, or basic classifiers. The most important section of this part then contains description of the state-of-the art mm-wave experimental setups. The core of the dissertation is composed as a selection of eight published papers complemented with the selected additional information on the hardware or experiments carried on. Three of the papers have dealt with RF impairments exploitation for transmitter authentication, two other focus on the implementation of low-complexity digital predistorters for power amplifier nonlinearity, and remaining three describe our millimeter-wave testbeds together with the achieved results of digital impairment compensation in 60 GHz band.
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Millimeter Wave Band Wireless Channel Measurement Techniques in Automotive Applications
Vychodil, Josef ; Kovář, Pavel (oponent) ; Masopust, Jiří (oponent) ; Derbek, Vojtěch (vedoucí práce)
This doctoral thesis deals with the millimeter wave band wireless channel measurement techniques in automotive applications. After a brief introduction into the topic and the summary of the current channel measurement techniques, the goals --- the development and assembly of a measurement system, capable of capturing all of the millimeter wave band channel features and practical measurements with this system, are set. The next part is the core of the dissertation --- the developed channel sounder is presented and a detailed description of used methods, principles, hardware and data processing is given. A significant part of the thesis is dedicated to the mitigation of the unwanted effects caused by the non-linear components in the measurement chain. The last chapters show the results of practical measurements of various scenarios --- the intra-car channels, vehicle to vehicle channels as well as vehicle to infrastructure channels.
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