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Drivers for power switching transistors GaN MOSFET
Fiala, Zbyněk ; Pazdera, Ivo (referee) ; Vorel, Pavel (advisor)
The thesis describes the procedure during the proposal of the driver circuits for the GaN MOSFET transistors, which are known for their fast switching especially. In the first instance of this thesis the issue of GaN MOSFET transistors is described and also the thesis describes the different types of MOSFET transistors in the way of their electrical and mechanical attributes. The specific type driver circuit is stated in the thesis, which was selected in the semestral thesis. For this circuit the boost converter with an output power 600W and high switching frequency 800kHz was proposed as an attempt measurement circuit. This boost converter was measured after its construction was done. The waveforms captured by the oscilloscope are commented also. In the conclusion the assessment is done about this new technology of power switching transistors.
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Antennas for energy transmission along the car roof
Škoda, Adam ; Hebelka, Vladimír (referee) ; Vélim, Jan (advisor)
The presented master’s thesis deals with antennas transmitting energy along conductive materials. Surface waves are used for energy transmission. According to its properties, the horn antenna was chosen for the problem solution. This thesis includes the theoretical analysis of surface waves, waveguides and horn antennas. The concept of antennas includes the comparison of two different materials and two different frequencies. From the set of 8GHz antennas, the structure of two antennas where one wearing the other was chosen as the most suitable. The FoamClad material was also selected due to achievement of better parameters and properties then material CuClad. This structure was designed by two identical horn antennas where the energy between them is transmitted via slot. The suitable feeding and parallel plates were designed, and further the current structure was modified to SIW structure. The designed antenna was manufactured and its properties were measured for further comparison with simulation results. Furthermore, achieved differences between simulated and real antenna are discussed.
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Wireles Flying Object Telemetry
Bednář, Martin ; Šimek, Václav (referee) ; Růžička, Richard (advisor)
This paper is engaged in specification, design and implementation of a telemetry module for flying object. Specifically, it focuses on the selection of the appropriate carrier frequency of the integrated circuit providing bidirectional communication to a sufficient distance and design of the protocol used in the transmission. Furthermore, the document focuses on the design of communication modules using these integrated circuits, altimeter sensor module, module to control the actuators and design of the application for mobile phones used to display the measured data. With regard to legislative and technical options, I chose a carrier frequency of 2.4 GHz. For this frequency is commercially available integrated circuit CC2511, which in cooperation with integrated circuit CC2591 should be able to provide telemetry range about 2 km. I chose BMP085 sensor for altitude measuring. It is communicating over I2C bus as well as a module for controlling the actuator, which uses a microcontroller ATMEGA48-20AU. The mobile phone communicates with the ground station via the USB bus.
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Microstrip Patch Antennas Fed by Substrate Integrated Waveguide
Mikulášek, Tomáš ; Polívka,, Milan (referee) ; Vlček, Čestmír (referee) ; Láčík, Jaroslav (advisor)
Dizertační práce je zaměřena na výzkum mikropáskových flíčkových antén a anténních řad napájených vlnovodem integrovaným do substrátu (SIW). Využitím vlnovodu integrovaného do substrátu pro napájení mikropáskové flíčkové antény dochází ke kombinaci výhodných vlastností obou struktur. Výsledkem je kompaktní anténní struktura, jejíž napájecí vedení neprodukuje parazitní záření a neovlivňuje tak vyzařovací charakteristiku antény. Práci lze z věcného hlediska rozdělit do dvou částí. První část práce (kapitola 2) je zaměřena na návrh flíčkových antén a jejich navázání na vlnovod integrovaný do substrátu. První dvě navržené flíčkové antény využívají vlnovod integrovaný do substrátu a štěrbinu nebo koaxiální sondu pro buzení lineárně polarizované vlny. Napájení koaxiální sondou je dále použito pro buzení kruhově polarizované flíčkové antény. Za účelem získání širšího pásma osového poměru je navrženo napájení flíčkové antény ve dvou bodech. Funkčnost všech anténních struktur je popsána pomocí parametrických simulací a ověřena realizací a měřením vyrobených prototypů antén. Prezentované napájecí metody představují nový způsob napájení pro mikropáskové antény využívající technologii SIW. Ve druhé části práce (kapitola 3) je pojednáno o implementaci štěrbinou napájené mikropáskové anténní struktury do malých anténních polí o velikosti 2x2 a 1x4. V případě lineární řady je uvažováno amplitudové rozložení pro optimální potlačení postranních laloků. Obě navržené anténní řady jsou ověřeny měřením a v porovnání s podobnými anténními řadami dostupnými v literatuře dosahují širšího pracovního pásma kmitočtů a vyššího zisku.
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Antenna for broadband impulse signal
Smutný, Martin ; Kořínek,, Tomáš (referee) ; Drexler, Petr (advisor)
The thesis describes retrievals of broadband antennas for VHF and UHF. It focuses on a compact antenna, potentially suitable for detecting electromagnetic impulses generated by electrical discharges in the dielectric oil in power transformers. This pulse signals are very steep with hundreds pico seconds rising edge. The thesis presents basic characteristics of antennas and selects those which have a major influence on the possibility of using the antenna in selected application. The appropriate antena is selected and proposal its geometrical parameters is discussed. The geometry of the selected antenna is designed for working bandwidth from about 200 MHz to about 1000 MHz. The newly designed double discon antenna is simulated and dimensions are optimized. Antenna is made and key characteristics of the antenna important for evaluate the ability of detecting the above-identified pulsed signals is measured. Antenna is compared with gain and characteristic of monocone antenna. Acquired knowledge and measured data are evaluated.
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In-car wireless power transfer
Cupal, Miroslav ; Polívka, Milan (referee) ; Raida, Zbyněk (advisor)
The thesis is focused on the design of antennas for wireless power transfer inside a car near the frequency of 8 GHz. In the last century, a number of scientists dealt with wireless transmission of energy with high power and long distances. Currently, attention is given to methods capable of transmitting energy with good effectively over a distance of meters for charging mobile devices, wireless sensors and other devices with low power consumption.
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Double ridge horn antenna for antenna measurement
Vašina, Petr ; Hertl, Ivo (referee) ; Láčík, Jaroslav (advisor)
The thesis deals with broadband antennas for measurement purposes. A ridged horn antenna has been selected for this concept, designed for the frequency range 0.9 GHz to 9 GHz. This work contains general theoretical description of antennas and further it focuses on a specific design of the ridged horn antenna, beginning with the calculation of its dimensions, modeling and optimization to obtain desired antenna properties. Finally, the antenna was constructed and measured. The reflection factor s11
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Design of reflector antenna for special radar applications
Kačmařík, Ivo ; Oliva, Lukáš (referee) ; Lukeš, Zbyněk (advisor)
The aim of this bachelor’s thesis was to design small parabolic reflector antenna in program CST Microwave Studio and it’s execution and verifying of it’s parameters by the laboratory measurements. Basic demands were rational proportions of the antenna and it’s good electrical properties, especially optimization of impedance matching and directional characteristics.
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Design and optimization of the helical antenna
Zelinková, Lenka ; Olivová, Jana (referee) ; Lukeš, Zbyněk (advisor)
The thesis contains the design of helical antennas for the assigned frequencies. The theoretical design is verified by parameter calculators. The design properties were verified in the computer simulator CST Microwave studio where the antennas were optimized to the maximum gain. The antennas intended as parabola feeds are completed with the designs of parabolas and focal distances between the antennas and the parabolas. Impedance matching by a quarter-wave transformer is designed for the antennas.
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