|
|
Antennas with metamaterial radomes
Martínek, Luděk ; Tkadlec, Roman (referee) ; Pítra, Kamil (advisor)
This thesis deals with microstrip antennas covered by the metamaterials. First, are described planar antennas, their problems and the emergence of surface waves. Surface waves can cause unwanted coupling among particular parts of the structure and can degrade its parameters. The problem can be solved using an electromagnetic band gap structure (EBG). These periodic structures are able to suppress surface waves in different frequency bands. It is shown how the EBG structure in the function superstate improve directivity and antenna gain. Radiation conventional microstrip antenna with metallo-dielectric EBG superstrate and with the purely dielectric double-layer superstrate is described. The both structures are designed and simulated in CST Microwave Studio program. Further is described the antenna radiation with so-called mushroom structure and metallo-dielectric EBG superstate. The structure is again designed and simulated in CST MWS program. Finally, there are two structures with metallo-dielectric superstate implemented and measured.
|
|
|
Planar Antennas on Electromagnetic Bandgap Substrates
Horák, Jiří ; Dědková, Jarmila (referee) ; Škvor,, Zbyněk (referee) ; Raida, Zbyněk (advisor)
Planar antennas are used in several technical applications. The family of planar antennas contains microstrip antennas, which are very popular due to the low weight, low profile, simple manufacturing and easy mass production. Lower gain and excitation of surface waves are disadvantages of microstrip antennas. The propagation of surface waves can be efficiently suppressed if the conventional substrate is replaced by an electromagnetic bandgap (EBG) substrate. Microstrip antennas on EBG substrates have been presented in an open literature for several years. Nevertheless, no published work is devoted to the design of EBG substrates, which can suppress surface waves at several frequencies those cannot be covered by a single bandgap. In order to reach optimum parameters of designed antennas, selected global optimization methods are applied (genetic algorithms, particle swarm optimization, ant colony optimization).
|
|
|
Antenna a LNA for multiband GNSS receiver
Ondráš, Michal ; Baran, Ondřej (referee) ; Záplata, Filip (advisor)
This project describesa microwave antenna for GNSS and low noise amplifier. Mikrostrip antenna is a modern type of antenna. This mikrostrip antenna is Dual – band antenna with circual polarization. The thesis describes how to make anantenna, what a circular polarization is, whata patch antenna is and what GNSS is. Low noise amplifier amplifies the antenna output signal.
|
|
|
Square type fractal antenna
Roháček, Peter ; Všetula, Petr (referee) ; Hebelka, Vladimír (advisor)
The bachelor thesis deals with analysis of fundamental parameters of antennas and methods of fractal construction. Attention is turn on microstrip antennas, where are discussed the basic properties, the pros and cons, methods of construction, power options and a demonstration of the theoretical proposal. These supporting documents were used for the actual design and optimization of the square fractal antenna in CST Microwave Studio program, which was subsequently implemented.
|
|
|
Circularly polarized textile-integrated antenna array
Rujzl, Miroslav ; Láčík, Jaroslav (referee) ; Raida, Zbyněk (advisor)
This bachelor thesis deals with the design of the right-hand circularly polarized antenna arrays operated in the ISM band 5.8 GHz. The planar antenna array is integrated into the 3D textile produced by SINTEX, which is used as upholstery on the roof of a car. In the thesis, several antenna models are described. Models operate with linear and circular polarization. Initial antenna designs were based on a microstrip technology. Later antenna designs are modified using substrate integrated waveguide technology. Finally, a three-element patch array with a coaxial excitation was fabricated and tested.
|
|
|
Modeling and optimization of patch antennas
Šídlová, Ludmila ; Láčík, Jaroslav (referee) ; Raida, Zbyněk (advisor)
This work is engaged in modeling of patch antennas. It describes various types of synthesizing the layout and designing the microstrip feeder or probe feeding. This work is focusing on modeling and creating a patch antenna for 6 GHz fabricated from ARLON 25N and fed by a microstrip. The layout is first calculated from required antenna parameters and substrate parameters. The optimization of the patch antenna is carried out in the program ANSOFT Designer, which analyzes planar structures by the moment method. The fabricated patch antenna is measured by a vector analyzer. Results of measurements and computations are compared in terms of frequency response of the standing wave ratio for the frequency interval from 5.5 to 6.5 GHz. The patch antenna is also modeled in the program COMSOL Multiphysics as a two-dimensional conical monopole with a coaxial feeding, and a three-dimensional patch fed by a microstrip; the design is optimized for the operation frequency 6 GHz.
|
|
|
Dual-port microstrip circularly-polarised antenna
Holek, Karel ; Horák, Jiří (referee) ; Lukeš, Zbyněk (advisor)
The thesis is focused at the design and the execution of a dual-port microstrip circularly-polarized antenna for the frequency of 2.4 GHz. The first part describes general knowledge about microstrip antennas, circularly-polarized, options of power supply, used medium etc. The second part of the thesis deals with the design and simulation of antennas with the use of software called CST Microwave Studio and Zeland IE3D. In the last part, confrontation of simulation and measurement results is provided.
|
|
|
Modeling of planar antenna loaded with ring resonators
Šrajbr, Michal ; Kovács, Peter (referee) ; Láčík, Jaroslav (advisor)
This bachelor’s thesis is focused on the design of the dual-band printed dipol loaded with split ring resonators. The principal of this antenna is described in the first part. The main focus is on the design and tuning of the split ring resonators on the required working frequency in the CST Microwave Studio program. These results are used for designing dual-band printed dipol loaded with split ring resonators working at resonance frequencies of 1,8 a 2,4 GHz. The simulation of this antenna was performed in the IE3D program Zeland. The designed dual-frequency printed dipole has been manufactured and measured.
|
|
|
Analysis of microstrip antennas
Kozák, Filip ; Polívka, Milan (referee) ; Štumpf, Martin (advisor)
This work deals with the method for analysis of one-port microstrip circuits which is called as contour-integral method. The general procedure for evaluating of important parameters concerning the analysis of microstrip antennas is given. Next, the geometrical parameters necessary for the calculation of elements in U and H matrices are numerically solved. With the help of these matrices, the input impedance or the reflection coefficient can be easily found.
|
|
|
Implantable circularly polarized antenna
Šebo, Richard ; Koudelka, Vlastimil (referee) ; Raida, Zbyněk (advisor)
Táto práca sa zaoberá novou miniaturizovanou kruhovo polarizovanou mikropáskovou anténou v tvare kruhu, ktorá bola navrhnutá pre Industrial, Scientific, and Medical pásmo (2.4 -- 2.5 GHz). Navhrnutá anténa bola vytvorená v ANSYS HFSS, najprv bola umiestnená do jendnovrstvého modelu ľudskej kože a jej parametre sú porovnané s pôvodným listom. Anténa je potom umiestnená do trojvrstvého modelu ľudského tkaniva a je pozorované ako iné prostredie a rôzna hĺbka implantácie ovplyvňuje jej parametre. Anténa bola optimalizovaná na dostupné substráty, vyrobená a zmeraná. Lineárne polarizovaná prijímacia anténa bola navrhnutá a vyrobená a bol zmeraný prenos medzi ňou a kruhovo polarizovanou anténou pri rôznych vzájomných orientáciach.
|
guest ::
