|
|
Antenna for universal transmitter
Daněk, Jan ; Láčík, Jaroslav (referee) ; Láčík, Jaroslav (advisor)
This work describes an electrically small antennas used for mobile devices in the ISM band. The aim of this work is to select an antenna for a universal transmitter/receiver working in the 868 MHz band. The work contains description of the universal transmitter/receiver, and a list of suitable antennas. Tolerance analysis is performed by numerical model. The proposed antenna is manufactured and measured.
|
|
|
Wideband rectangular patch antenna
Teplý, Tomáš ; Puskely, Jan (referee) ; Láčík, Jaroslav (advisor)
This thesis focuses on the design microstrip antennas with a maximum bandwidth. First discussed are the standard types of supply of these antennas with main attention to the coaxial power supply (power probe) and L-probe. Furthermore, the properties of these types of power examined in the program CST Microwave Studio. The results obtained are used for the design of rectangular Patch Antenna with a maximum bandwidth. The proposed antenna is modeled in CST Microwave Studio program and then implemented. The result of this work is a microstrip antenna, the impedance bandwidth is 32,14%.
|
|
|
Computer design of a digital radio link
Havel, Ladislav ; Nováček, Zdeněk (referee) ; Láčík, Jaroslav (advisor)
The Terrestrial digital radio links are used for transmitting digital information between fixed stations on a line of sight of a radio path. Each digital radio link has many characteristics and parameters for transmission. We require technical parameters in the design of digital radio link such as data rates and capacities. In this design we should take into account most effects of the electromagnetic waves propagation, if we want to meet user technical requirements of the link and if that link may correctly transmit digital signals with minimum errors. Prediction methods for the design of terrestrial line of sight systems are still in progress. Some effects of electromagnetic waves propagation and methods of the digital radio link design depend on natural variability and climate. The goal of this diploma thesis is to investigate methods for the design of terrestrial line of sight links with taking into account of ITU recommendation. Make computer program which implement this investigate methods
|
|
|
Antenna for smart watch
Hájek, Miroslav ; Láčík, Jaroslav (referee) ; Cupal, Miroslav (advisor)
The objective of this work is a create a smart watch antenna, that will operate in two frequency bands. These are GSM (1.8 GHz) and ISM (2.4 GHz) bands. This antenna must be able to work when be placed on an elastic material that is used as a smart watch belt. Antennas options are analyzed and their suitability for given use. There is also an antenna model in CST microwave studio, where all the simulations were made. The antenna is also simulated on human hand models that have different dimensions and tissue ratios.
|
|
|
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.
|
|
|
Permittivity measurement of materials by coax probe
Ryba, Ivan ; Oppl, Ladislav (referee) ; Láčík, Jaroslav (advisor)
This thesis describes possibilities of measuring permittivity of various materials, especially with coaxial probe method. It describes character of measuring method, hardware requirements and how to calculate values from the measured. Objective of this thesis is to design measuring station for measuring permittivity of materials with coaxial probe including calibration set. Code in Matlab is also programmed and whole station is tested with known samples to discuss measurement accuracy.
|
|
|
Design of circular polarized antenna for 2.4 GHz
Hase, Michal ; Lukeš, Zbyněk (referee) ; Láčík, Jaroslav (advisor)
In this thesis, I introduce two types of circularly polarized rectangular microstrip antennas at 2.44 GHz. First type has direct fed and the second has two inputs for fed. In first case is used a stub to make the frequency with minimum return loss and equal to the frequency with minimum axial ratio. In second case is use the power splitter to divide the wave in to two lines with phase shift 90° for feeding the patch. In this thesis is described, how to get the best results of Axial Ratio.
|
|
|
Slot antenna
Dvořák, Petr ; Horák, Jiří (referee) ; Láčík, Jaroslav (advisor)
This thesis discusses Slot antennas that are based in gap waveguide technology, which allows them to work with high frequency signals. It contains theoretical findings about antennas and waveguides, which are later used in the design. The practical section of this thesis concentrates on designing a specific gap waveguide for 10 and 24 GHz frequencies, starting with modeling and parameter optimalization. This gap waveguide is then used as a base for slot antenna design. The final antenna is designed for frequency of 10 GHz, for both linear and right-handed circular polarizations. With right-handed circular polarization, the achieved band was approximately 1.41 GHz, while the gain was 7,6 dB.
|
|
|
Antenna system for wireless microphones
Bartoš, Adam ; Lukeš, Zbyněk (referee) ; Láčík, Jaroslav (advisor)
Master's thesis deals with the design of an antenna system for wireless sound transmission used mainly in professional sound reinforcement. The introductory part deals generally with wireless microphones, frequency bands used and proven antenna types. Next, this work deals with signal distribution that is realized using the antenna splitter. The antenna parts is focused on easy production and real usage, therefore were selected antennas with appropriate properties suitable for small series production. This thesis includes simulation of each device, their real construction design and measurements of built prototypes and final products. All three produced devices – the rack splitter, /4 antenna and Helix antenna are fully working, achieve good parameters and are ready for further manufacturing and easy modifications in case of frequency band change requirement. The conclusion includes an overall assessment of the results achieved.
|
|
|
Wearable rectifying antenna for RF energy harvesting
Kokolia, Martin ; Horák, Jiří (referee) ; Láčík, Jaroslav (advisor)
The aim of this thesis is to design and rectena that would be able to integrate into a cloth thanks to use of textile substrate. The first part deals with the possibilities of using various communication channels and services for maximizing the useable power. Attention is focused mainly on the use of textile materials for implementing microstrip circuits. It is made valorization of all the typical characteristics and problems using different fabrics as a microwave substrate and the possibilities of realization of conductive structures of microwave patch antenna and microstrip circuits. At the second part are identified parameters and constraints used for the design of the overall device with a rectifying antenna, which will be after the verification of the function in real implementation used for the final concept using textile structures. The design is verified by simulations by CST Microwave Studio and Microwave Designer. The initial design is being gradually extended by other concepts, the use of other materials and technologies. Several design are made, their properties evaluated and the best ones are then compared based on real measurements.
|
guest ::
