|
|
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.
|
|
|
HF and IF circuits of shortwave radiostation
Šnajdr, Václav ; Vágner, Petr (referee) ; Lukeš, Zbyněk (advisor)
The study, description, design and implementation of selected blocks of multiband shortwave radio station are dealt with in the thesis. Focus is placed on the concept of multiband shortwave radio stations, with an emphasis on high frequency and intermediate frequency circuits. The first chapter is devoted to description of the transceiver block diagram which is designed as superheterodyne. The design of bandpass input filters, intermediate frequency crystal filters and output filters is described. Simulation results and the measured characteristics of the implemented functional blocks are presented. Furthermore, the amplifier circuits which maintain impedance matching of individual blocks are discussed. SSB signal generation in the transmitter part of radio station and final stage power amplification are depicted.
|
|
|
Impedance matching of a transmission line in Matlab
Straka, Zdeněk ; Láčík, Jaroslav (referee) ; Štumpf, Martin (advisor)
This bachelor’s thesis is aimed at the impedance matching of transmission lines and at understanding of the Smith chart plotting. In the text are described the basic features of the transmission line theory, i.e. the behavior of voltage and current along the lines in different situations. The construction of the Smith chart is described in detail. The Smith chart serves for the transformation of impedance and reflection coefficient along the transmission line. In conclusion, advantages and disadvantages of the matched transmission line are discussed. The project presents a demonstration program using examples. The program is used for illustrative example of the matched impedance and the behavior of voltage and current along the lines in different situations
|
|
|
Mini-whip antenna
Pařízek, Tomáš ; Lukeš, Zbyněk (referee) ; Raida, Zbyněk (advisor)
The thesis deals with the impedance matching of electrically very short antennas to the real resistance 50 . The antenna is considered as an input of an emitter follower, which plays the role of the impedance transformer. This follower transforms a large complex input impedance, which is typical for electrically short antennas, to a real output resistance. The output impedance was matched by appropriate matching circuitry to 50 in the frequency band of operation.
|
|
|
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.
|
|
| |
|
|
3D printed circularly polarized patch antenna
Drápal, Jakub ; Kaděra, Petr (referee) ; Láčík, Jaroslav (advisor)
The bachelor thesis deals with circularly polarized patch antennas. In this work, circular polarization is achieved by inhomogenous substrate. The first part summarizes the basic theoretical knowledge about the patch antennas, the shapes of the patch antennas, the excitation methods and the generation of circular polarization. In the next section, the design of a circularly polarized patch antenna on an inhomogeneous substrate is described, and several antenna concepts are proposed and compared with each other and with a conventional antenna. The effect of shaping the inclusions and their gradation in the substrate and the insertion of the inclusions around the centre conductor in the substrate is investigated. The last section is devoted to the realization of the designed antennas by 3D printing method and comparison of simulations from ANSYS HFSS software with measurements of the antennas.
|
|
|
Methods of acoustic signal sources impedance matching for their further processing
Havelková, Nikola ; Kubánek, David (referee) ; Koton, Jaroslav (advisor)
The purpose of this bachelor thesis is to get acquainted with the theoretical areas related to the issue of impedance matching using the so-called DI boxes. It is mainly the theory of balanced and unbalanced signal, parameters typical for DI boxes (THD, impedance, bandwidth, dynamic range, etc.), knowledge about the transformer, respectively about the coils, or last but not least the issue of operational amplifiers, which is for designing of active DI box absolutely essential. The specifications of the designed DI box based on this theory are subsequently determined and compared with commercially available models. The main target is to achieve better figures or at least get closer to them. Furthermore, the circuit diagram is designed and optimized to achieve predetermined parameters using simulation in the Multisim program from National Instruments. Regarding the resulting specifications of the DI box, a printed circuit board is designed to build a prototype of the device. After its completion, a test gauging using APx525 is done and the results are compared to the target figures.
|
|
|
Methods of acoustic signal sources impedance matching for their further processing
Havelková, Nikola ; Kubánek, David (referee) ; Koton, Jaroslav (advisor)
The purpose of this bachelor thesis is to get acquainted with the theoretical areas related to the issue of impedance matching using the so-called DI boxes. It is mainly the theory of balanced and unbalanced signal, parameters typical for DI boxes (THD, impedance, bandwidth, dynamic range, etc.), knowledge about the transformer, respectively about the coils, or last but not least the issue of operational amplifiers, which is for designing of active DI box absolutely essential. The specifications of the designed DI box based on this theory are subsequently determined and compared with commercially available models. The main target is to achieve better figures or at least get closer to them. Furthermore, the circuit diagram is designed and optimized to achieve predetermined parameters using simulation in the Multisim program from National Instruments. Regarding the resulting specifications of the DI box, a printed circuit board is designed to build a prototype of the device. After its completion, a test gauging using APx525 is done and the results are compared to the target figures.
|
|
|
Mini-Whip Antenna
Pařízek, Tomáš
The thesis deals with the impedance matching of electrically very short antennas to the real resistence 50 Ω . The antenna is considered as an input of an emitter follower , which is plays the role of the impedance transformer. This follower transforms large complex input impedance, which is characteristic for electrically short antennas, a real output resistance. The output impedance of assistance was matched by matching circuitry to 50 Ω in the frequency band of operation.
|
guest ::
