Past theses

Theses Completed

Bachelor’s Thesis

A High-Frequency Power Amplifier

The author focuses on designing and implementing a high-frequency power amplifier with a continuous output power of at least 100 W. This amplifier is built using a three-stage structure, with the first two stages forming a broadband driver amplifier. The power stage covers the frequency band from 50 to 500 MHz. In terms of the components, the designing process included the circuit schematic, PCB layout, cooling setup, and Arduino-based control system. The overall functionality was verified through measurements.

Bachelor’s Thesis

Controlling a High-Frequency Source and Measuring the Reflected Power

The aim rests in designing a scheme to control a high-frequency source, involving reflected power measurement and the selection of components according to preset parameters. The parts designed and stages performed include the feeding and cooling setup, printed circuit board elements, assembly, and testing. Regarding the advantages, drawbacks, practical applicability, and possible improvement, these are all broadly discussed, together with whether the aims and requirements have been met.

Bachelor’s Thesis

A System for the Measurement and Control of Pressure in a Vacuum Apparatus

The project was conceived to create, by using regularly available components, a setup for measuring and controlling the gas pressure in a vacuum apparatus. After conducting preliminary theoretical investigation, the author selected suitable elements and integrated these together to form a functional unit that includes relevant hardware and software. The system uses an automatic regulator to easily reach the desired operating point upon further research.

Master’s Thesis

A Simulator of the Partial Discharge Signal in the UHF Band

The thesis discusses the generation and effects of partial discharges in dielectric materials, characterizing their classes, parameters, and electromagnetic radiation in the UHF band. The set of tasks performed includes simulating a UHF signal and designing a device to reproduce this signal as accurately as possible. Further, a comprehensive labdesk to simulate and detect discharges is proposed; the design naturally integrates tools that analyze the time and frequency characteristics.

Project Synopsis

A Modulated Current Source to Feed a Noise Source of an Electromagnetic Field

When measuring very weak signals, we can employ the sychronous detection principle, where the intensity of the carrier quantity is modulated at a frequency to be subsequently demodulated by using the same frequency. Experiments that involve the detection of a very weak microwave noise field require designing, fabricating, and verifying an electronic source of modulated current to feed the noise emitters. This source will eventually be integrated in both a microwave radiometry system to measure the parameters of materials and in the tomography. The project involves designing, developing, and measuring electronic circuits, with circuit simulations where necessary.

Project Synopsis

External Detection of the UHF Signal of Partial Discharges in Power Transformers

At the Department of Theoretical and Experimental Electrical Engineering, a unique setup was developed to detect partial discharges in power transformers. The system is currently in regular use at the South Moravian Region’s Dukovany nuclear power plant. The concept relies on the multi-channel reception of an irradiated electromagnetic signal; the signal’s frequency is between hundreds of MHz and the microwave band, spanning from tens of picoseconds to nanoseconds. This system features a drawback in that sensing antennas have to be installed in the transformer vessel. Recently, the everyday operation of the setup has produced the requirement to sense the signal outside the vessel, as the structural gaps allow the signal to leak inside. For such purposes, an external sensor has already been developed and partially tested. The assignment then rests in expanding the sensor testing cycles to enable the sensor to approach real-world conditions and in designing and verifying the options to sense the signal with the external sensor while eliminating the impact of external disturbance. Thus, the applicant is expected to work with vf measuring tools and to design applicable electronic circuits.