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Low Noise amplifier for 8,4 GHz
Svoboda, Libor ; Vágner, Petr (referee) ; Kasal, Miroslav (advisor)
This project deals with methods of design and realization of low noise microwave amplifier for X-band. The first part describes this issue at a theoretical level. Thus it contains a detailed analysis of microstrip line and its circuit components. It is followed by some specifics of microstrip filters and with mention of microwave heterojunction transistors. The last chapter of the theoretical part describes design of small-signal amplifier with focus on low noise figure. The second part, practical, shows a concrete procedure of two-stage LNA design with HEMTs, using CAD tool Ansoft Designer. This section, as well as the bachelor’s thesis, is finished with realization of amplifier and analysis of its properties.
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Multilayer textile antenna array
Hermány, Roman ; Tobola, Pavel (referee) ; Raida, Zbyněk (advisor)
Thesis focuses on the design and development of three possible methods to power the serial patch array and optimization of the chosen design. The antenna array is conceived as a multi-layered structure formed on a 3D textile substrate. The objective of this work is to identify the best possible configuration of antenna array for the use in automotive and aerospace industry. The first concept – array coupled by near microstrip line – proved in the case of the more serial elements as non-functional. The second concept – aperture coupled array – is unsuitable for use in close proximity to the electrically conductive shell of the aircraft. The third concept – array coupled with textile integrated waveguide – seems like the best possible solution. The design of the array coupled with textile integrated waveguide was optimized in consideration of the production process. The impedance bandwidth of this proposed three elements antenna is 890 MHz, the gain in the main lobe direction is 11.8 dBi.
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Quarter-mode four-element antenna array
Janoušek, Jiří ; Fiala, Pavel (referee) ; Raida, Zbyněk (advisor)
Thesis deals with problematics of Compact Circularly Polarized Antenna Based on Quarter-Mode Substrate Integrated Waveguide Sub-Array and process. It also solves a complex structure of microstrip power distribution network. The goal was to create a~physical functioning model of this antenna and to measure its attributes in free space and also near the human body. Theoretical part of this work is taking on the calculation of parameters of the proposed antenna. Practical part is then solving modelation and simulations in program ANSYS HFSS. Physical model of the antenna was not created and some flaws were found in the presented model of the microstrip power distribution network. A possible solutions were proposed to eliminate these flaws.
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Design of the LVDS bus with hight EMC immunity
Klauda, Zbyněk ; Fiala, Pavel (referee) ; Kroutilová, Eva (advisor)
My thesis deals with project of LVDS busbar with high resistivity with regard to disturbance from surroundings and radiation undesirable electromagnetic waves into its environment. Project of LVDS busbar was elaborated by numeric methods and it was suggested optimal solution of the shape and material of multiply technology DPS. The project was realized on desired driving-point impenance of busbar Z=100 ohm with frequency f1=100 MHz of the first harmonic component rectangular signal of defind modality, entering and diagonal edge.
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Defected ground planar filters
Tomíček, Martin ; Vágner, Petr (referee) ; Raida, Zbyněk (advisor)
In the bachelor´s thesis, the microstrip low-pass filter with the defected ground is described. The project deals with the design and the simulation of the filter in Ansoft Designer, confrontation of results between simulation and realized low-pass filter and the discussion of obtained results.
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System for control of high-frequency power source with reflected power measurement
Zoufalý, Ondřej ; Drexler, Petr (referee) ; Juřík, Karel (advisor)
This thesis briefly describes the function of the selected high-frequency technology and its use. Furthermore, the thesis contains a discussion of the method of designing a system for control of high-frequency power source with reflected power measurement, after which the selection of suitable components is carried out based on pre-selected parameters. Subsequently, the method of powering and cooling the system is proposed. This is followed by the actual assembly of the system and testing of its functionality and measurement of system parameters. In the last part, selected parts of the printed circuit board of this system are described and justified.
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Multilayer textile antenna array
Hermány, Roman ; Tobola, Pavel (referee) ; Raida, Zbyněk (advisor)
Thesis focuses on the design and development of three possible methods to power the serial patch array and optimization of the chosen design. The antenna array is conceived as a multi-layered structure formed on a 3D textile substrate. The objective of this work is to identify the best possible configuration of antenna array for the use in automotive and aerospace industry. The first concept – array coupled by near microstrip line – proved in the case of the more serial elements as non-functional. The second concept – aperture coupled array – is unsuitable for use in close proximity to the electrically conductive shell of the aircraft. The third concept – array coupled with textile integrated waveguide – seems like the best possible solution. The design of the array coupled with textile integrated waveguide was optimized in consideration of the production process. The impedance bandwidth of this proposed three elements antenna is 890 MHz, the gain in the main lobe direction is 11.8 dBi.
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Quarter-mode four-element antenna array
Janoušek, Jiří ; Fiala, Pavel (referee) ; Raida, Zbyněk (advisor)
Thesis deals with problematics of Compact Circularly Polarized Antenna Based on Quarter-Mode Substrate Integrated Waveguide Sub-Array and process. It also solves a complex structure of microstrip power distribution network. The goal was to create a~physical functioning model of this antenna and to measure its attributes in free space and also near the human body. Theoretical part of this work is taking on the calculation of parameters of the proposed antenna. Practical part is then solving modelation and simulations in program ANSYS HFSS. Physical model of the antenna was not created and some flaws were found in the presented model of the microstrip power distribution network. A possible solutions were proposed to eliminate these flaws.
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Harvesting of emelctromagnetic energy in 24 GHz band
Rokos, Lukáš ; Pokorný, Michal (referee) ; Raida, Zbyněk (advisor)
The thesis describes basic principles of an electromagnetic energy harvesting and its potential use. To gain the energy, a rectenna (rectifying antenna) is selected. The rectenna consists of a patch antenna, a matching circuit and a rectifier circuit. The thesis describes a design of the patch antenna operating at 24 GHz and its matching to the microstrip line with the characteristic impedance 50 . Then, the circuit for matching the rectified is designed using an open-ended stub. The last part of the thesis describes several types of rectifier circuits to be used potentially. Functionality of the designed rectenna has been verified in ANSYS Designer.
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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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