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Energy harvesting demonstrator
Kaděra, Petr ; Mikulášek, Tomáš (referee) ; Mrnka, Michal (advisor)
This semestral thesis is focused on radio frequency energy harvesting. The thesis describe parts of network that are essential for conversion of radio frequency energy into DC. It deals with various solutions to the given problem. The aim of the thesis is to design a proper antenna with supplemental circuits for commercial Powercast P2110B receiver which combines the function of a rectifier and a step-up DC/DC converter.
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Heart rate measurement using pulse oximetry on unconventional parts of the human body
Varmužová, Zdeňka ; Mrnka, Michal (referee) ; Cupal, Miroslav (advisor)
This study deals with the method of measuring heart rate using pulse oximetry. It describes the basic principles of this method for determining both heart rate and blood oxygenation. It examines the possibilities of placing the sensor on non-standard places of the human body. It also discusses the possible shortcomings of the method as well as the inaccuracies of measurements in certain places on the body and the possibilities of mounting the sensor and the use of the product in ordinary life. Later it presents the design for the heart rate measuring device used on the selected body part, that is forehead, and compares it with commercialy available products.
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Antena integrated to automobile seat
Gulda, Tomáš ; Mrnka, Michal (referee) ; Cupal, Miroslav (advisor)
This thesis is focused on the design of the antenna integrated to automobile seat. Thesis explains the basics of RFID technology, and how RFID works. Especially explains the design of tag, which works in the UHF band. The tag was designed in the CST Microwave studio, where simulations were realized to verify basic properties of the tag such as S11 parameter and directivity. The thesis also contains simulation of the impact of automobile seat on the directivity. Here is the description of how the antenna was made on a textile substrate and here are also measured properties of the antenna.
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Directive Dielectric Resonator Antenna
Mrnka, Michal
Relatively directive, single element, linearly polarized, dielectric resonator antenna for the ISM band applications (5.8 GHz) is presented in the paper. Its operation is based on the excitation of higher order modes inside a cylindrical dielectric resonator antenna of low relative permittivity material (εr= 6.15) fed by an aperture coupled microstrip line. The behavior of the mode properties inside the resonator is studied and geometry providing maximum gain is determined. Measurement results are given and compared with simulations results obtained in CST Microwave Studio in order to confirm the correct operation of the antenna.
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Perforated Dielectrics and Higher-Order Mode Dielectric Resonator Antennas
Mrnka, Michal ; Bonefačić, Davor (referee) ; Mrozowski, Michal (referee) ; Raida, Zbyněk (advisor)
Práce se zabývá buzením vyšších módů v kvádrových a válcových dielektrických rezonátorových anténách pro účely zvýšení zisku. Pomocí numerických simulací jsou studovány vlastnosti a limity anténních prvků. Je zkoumáná vzájemní vazba mezi dielektrickými rezonátorovými anténami pracujícími s vyššími vidy a na základě výsledků je možno usuzovat o vhodnosti těchto prvků k popužití v anténních řadách. V práci je popsán analytický model efektivní permitivity perforovaných dielektrik, který respektuje anizotropní povahu tohoto materiálu. Model je založen na Maxwell Garnettové aproximácií nehomogenních materiálů. Dále jsou studovány povrchové vlny na perforovaných substrátech a je ověřena použitelnost teoretického modelu i v tomto případě. Nakonec jsou studovány dielektrické rezonátorové antény vytvořené pomocí perforací v dielektrickém substrátu a je demonstrováno zhoršení určitých vlastností takových antén.
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Radiation efficiency measurements of dielectric resonator antennas using Wheeler method
Sedler, David ; Mikulášek, Tomáš (referee) ; Mrnka, Michal (advisor)
Bachelor thesis discusses the dielectric resonators as antenna elements. This work includes description field rectangular resonators, possible dielectric materials, shapes and feeds, e.g. coaxial probe, microstrip line or substrate integrated waveguide. In project is listed measuring radiation efficiency of antennas in general and method used wheeler cavity. Bachelor thesis contains design of waveguide with proposal of dielectric resonator. Design of the antenna was conducted in software CST Microwave Studio and there are demonstrated results of simulations. Radiation efficiency of the dielectric resonator antenna was measured by the Wheeler method and the efficiency received from the measured gain. The work included the measured results together with a comparison of the measurements of both methods and simulations.
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Substrate integrated dielectric resonator antenna
Jedlička, Lukáš ; Horák, Jiří (referee) ; Mrnka, Michal (advisor)
The bachelor´s thesis deals with the design of the dielectric resonator antenna in the microwave band X, where the resonator is made by air perforations. The antenna is made by two layers. The antenna is supplied by the substrate integrated waveguide. The design of the dimensions to achieve the desired resonance frequency of the dielectric resonator and integration of resonator is described. The whole antenna is designed in the CST Microwave Studio software.
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Wireless power transfer by inductive coupling for biomedical applications
Studený, Jakub ; Dřínovský, Jiří (referee) ; Mrnka, Michal (advisor)
The bachelor thesis deals with wireless power transfer implemented using a couple of inductively coupled planar coils. A procedure for designing planar coils using the Wheeler method is described as well as the process of simulating wireless transmission in a 3D electromagnetic field simulator. The conclusion of the thesis is devoted to the implementation of the designed coils with adaptive circuits, measurement of transmission by vector analyzer, investigation into the impact of coil distance, and mutual rotation of the coils and the materials interposed the between coils.
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Vibrational energy harvesting demonstrator
Uhliar, Marek ; Götthans, Tomáš (referee) ; Mrnka, Michal (advisor)
The aim of the thesis is to solve the problem of energy collection from vibrations, transformation into electric energy, which can be suitably used by the end device. In the next section, the reader is acquainted with possible circuits that can be used to process the collected electrical energy. The last part of the thesis deals with the design of the auxiliary circuits for energy collection and with the design of the demonstration device, which will use the converted energy to measure the air temperature and humidity. The measured values will then be displayed on the LCD.
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Energy harvesting demonstrator
Kaděra, Petr ; Mikulášek, Tomáš (referee) ; Mrnka, Michal (advisor)
This semestral thesis is focused on radio frequency energy harvesting. The thesis describe parts of network that are essential for conversion of radio frequency energy into DC. It deals with various solutions to the given problem. The aim of the thesis is to design a proper antenna with supplemental circuits for commercial Powercast P2110B receiver which combines the function of a rectifier and a step-up DC/DC converter.
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