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Planar bandpass filter with asymmetric resonators
Cholasta, Lukáš ; Kovács, Peter (referee) ; Raida, Zbyněk (advisor)
In this Bachelor thesis the microstrip bandpass filter with asymmetric resonators is described. In this work, the proposal, simulation, construction and resulting confrontation parameters realized microstrip bandpass filter in programme Ansoft Designer are described. In the introduction the problems analysis micro-wave integrated circuitsis are described, further the proposal of a simulation microstrip bandpass filter in programme Ansoft Designer is solved. In the third part of the bachelor thesis the optimalization of the filter for technology of production and realization of the filter are solved. In the conclusion the results of measurement of the realized filter and comparison with simulation are introduced.
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Suppression of side lobes of an antenna array by unequal power distribution on the elements
Saloka, Samuel ; Mikulášek, Tomáš (referee) ; Špůrek, Jan (advisor)
This bachelor thesis is focused on the design of an antenna array with four patch antennas. In the first part, the theory of a microstrip antenna and power divider with equal and unequal power distribution on elements design are summarized. In the second part, calculations necessary for the design of the antenna and both arrays are found. The third part contains modeling, optimizations and simulation results of the individual models and consequently the assessment of the results. A summarization of the measured results as well as photo documentation of the produced structures are in the fourth part. Conclusion of the entire work and its results are deliberated in last part.
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Stacked Yagi antenna for 60 GHz frequency band
Janečka, Martin ; Polívka, Milan (referee) ; Raida, Zbyněk (advisor)
This diploma thesis deals with the design and simulation of multi-layer stacked Yagi antenna at the frequency of 60 GHz. At work are proposed and compared two ways of antenna feeding methods. Based on the results obtained, antenna is fed by substrate integrated waveguide. The proposed antenna has been optimized in terms of gain and impedance matching at the specified frequency. The correct functionality of the antenna was verified by simulation program CST MWS 2011. Simulation results were verified experimentally.
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RF power meter
Hlaváč, Štěpán ; Jedlička,, Petr (referee) ; Drexler, Petr (advisor)
This master’s thesis describes various principles of measurement of electromagnetic waves in a free space and on a line. Used sensors and their real parameters are given for every method. The analysis of protections of high-frequency inputs of measuring instruments is done here and the most suitable method and protections of input for realization are chosen. The analysis of design of secondary protection of high-frequency input is done in this project. The protection of input is realized and measured. The suitable method of measurement is chosen as well as the sensor for measurement of power. The block diagram and circuit diagram of the meter of power are designed. According to designed conception the measuring instrument for measurement of power is realized and its single qualities are measured during the realization. In the final part its precision is measured and the evaluation of results is done.
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Modeling of microwave structures based on SIIG
Teplý, Tomáš ; Horák, Jiří (referee) ; Láčík, Jaroslav (advisor)
Well-known dielectric image guide reach in millimeter-wave interesting results. Compared to a conventional types of lines and waveguides is characterised by low-through loss for frequencies approaching 100 GHz. This work is detail focused to basic characteristics and especially type of perforate highpermitivity substrate for obtain implemented waveguide to dielectric board (SIIG). The work also contains couple suggestions for various transitions from a commonly used lines and waveguides. Simulation results using finite element method is achieved attenuation values below 2 dB, which corresponds to a 2 cm length and include a waveguide itself with a pair of transitions. Finally, this work also designed the production method and SIIG applicatoin in practicle.
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Miniature antenna for mobile applications
Šmarda, Marek ; Švanda,, Milan (referee) ; Pokorný, Michal (advisor)
This work deals with the most famous constructions of planar antennas. The work analyses selected methods of connecting planar antennas' charging with the possibility of impedance adaptation. An important part of the work consists of description of techniques for increasing bandwidth and conversely techniques for reducing the dimensions which are important for the design of planar antennas for mobile devices. The antennas were designed by means of theoretical basis and their properties were examined in the electromagnetic field simulator. The selected antenna model was constructed and its parameters were measured experimentally. The matching circuit for the antenna to tune it to different resonant frequencies was designed and constructed.
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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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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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Design of log-periodic antenna
Kliha, Marek ; Nováček, Zdeněk (referee) ; Láčík, Jaroslav (advisor)
This diploma thesis deal with the design of log-periodic antenna. The log-periodic antenna is self-complementary and broadband antenna. Antenna self-complementary structures are described only by angles. Input impedance of log-periodic antenna is equal to theoretical impedance ohms. The input impedance and radiation patterns of broadband antenna structures are independent of frequency over theoretically unlimited bandwidths. The log-periodic antennas provide linearly polarized radiation pattern. In this thesis is designed antenna for bandwidths 1 to 5GHz. In this diploma thesis is introduced design balanced unit, this is compound broadband balun and broadband impedance transformer. The broadband balun is based on conversion of microstrip line to balanced stripline. The Klopfenstein impedance taper is used for design. For simulation was used software from firma Zeland software IE3D.
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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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