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Low-profile directional antenna
Žúrek, Dan ; Pítra, Kamil (referee) ; Láčík, Jaroslav (advisor)
This diploma thesis deals with a study of low-profile directional antennas, followed by design and optimization of parabolic reflector antenna in centimeter and millimeter band. The first part of this work is focused on the analysis of several kinds of directional antennas, mainly on parabolic reflector and on SIW technology, which will be used for final antenna realization. The next part of this project is about the particular concept of the substrate integrated parabolic antenna for 60 GHz ISM band, its simulation and optimization in the CST Microwave Studio software. The final part of this thesis is devoted to the results achieved.
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Antennas for milimeter-wave bands
Pítra, Kamil ; Svoboda, Petr (referee) ; Raida, Zbyněk (advisor)
This thesis describes design and experimental verification of three types of the wideband antenna Bow-tie antenna, Vivaldi antenna and Spiral antenna. The tracked parameters are bandwidth, input impedance, gain and directivity patterns. Next step is design of millimeter-wave horn antennas. Attention is turned to the proper construction of a wideband feeder of the horn. For the final antenna structure, a bow-tie dipole and a Vivaldi antenna were chosen. The antenna construction is aimed to provide a wide bandwidth on one hand and a high gain on the other hand.
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SIW slot antenna
Martinec, Matěj ; Puskely, Jan (referee) ; Pítra, Kamil (advisor)
This work is dealing with the design of waveguide slot array antenna and SIW slot antenna with coaxial and microstrip feed operating in 5,6 GHz frequency in Wi-Fi frequency band of IEEE 802.11ac standard. For design of these antennas were used calsic methods and each of this parts were optimised in CST Microwave Studio. In this programme were optimised parameters of each part to occupy widest bandwidth of antenna, which was in conflict with the proper function of antenna. All antennas were compare between each other in light of selected parameters and suitable antenna has been chosen.
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Antennas for GSM bands
Rousek, Jiří ; Pokorný, Michal (referee) ; Pítra, Kamil (advisor)
Bachelor thesis deals with miniaturization techniques of the planar inverted-F antenna (PIFA). In bachelor thesis were simulated antennas for the GSM bands using meandering of the radiating patch, capacitive load and U-slolts. Influence of parameters of each miniaturization techniques on the antenna size and parameters were studied. The process of designing the antennas is described in detail. Selected models of antennas were adapted to given dielectric substrate and constructed. The measured results are presented and compared with simulations.
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Beam Shaping Circuits for L Band Antenna
Kalina, Ladislav ; Pítra, Kamil (referee) ; Urbanec, Tomáš (advisor)
This thesis contains design of beamforming network designed for passive radar antennas. The first part contains theory of passive radars and beamforming networks. The next part implies design of beamforming network at the block digram level. Then are choosed circuits for amplitude and phase control, including the design of control communication. It follows by realization of IQ phase shifter and his automatic measurement. Based on this results is phase shifter adjusted and PCB of 2x2 beamforming network is designed. Last part includes design of control application (Matlab) and control program for STM32F407VG microcontroller.
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Reconfigurable slot antenna array
Weigel, Filip ; Pítra, Kamil (referee) ; Raida, Zbyněk (advisor)
This master's thesis deals with the basic principles of slot antennas. Models of antennas were simulated in a selected electromagnetic simulator CST MICROWAVE STUDIO (CST MWS). There are several models of slot antennas which are optimized for communication in the car at a frequency 8 GHz.
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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.
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Patch antenna array for IFF band
Mička, Josef ; Pítra, Kamil (referee) ; Láčík, Jaroslav (advisor)
This master thesis deals with designing and implementing an antenna array for the IFF band. The design includes an antenna element simulation and a feeding network design for the antenna array. The antenna element is designed as broadband and has an SWR of less than 1.5 in each band. Two stacked patches are used to achieve the required bandwidth. The patches are fed through a slot. An asymmetric stripline line is used for the feeding network. The simulated antenna array shows good impedance matching and gain properties. The final part of the master thesis compares the measured results with the simulated results. Finally, an attempt is made to improve the SWR of the manufactured antenna array.
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Patch antenna with EBG substrate
Cepek, Tomáš ; Pítra, Kamil (referee) ; Hebelka, Vladimír (advisor)
The aim of the thesis is to describe EBG substrate and exminate his influence on some types of antennas and choose one of them for realization. In first part this thesis describes the paramaeters of antenna in generall, in the second part is dedicated to introduction with EBG substrate mainly on the surface with the high impedance (HIES). The third part deals with the simulations of microstrip patch antennas with EBG substrate and without EBG substrate. In the last parts was designed and optimized antenna using superstrate.
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Microstrip lowpass filter
Kubín, Petr ; Pítra, Kamil (referee) ; Vágner, Petr (advisor)
This thesis is focused on the design of an elliptic microstrip low pass filter. In the introduction, there is discussed theory of the filter design with discrete components. Then, the following part describes the design of the microstrip filter with distributed parameters. To simulate the characteristics of the designed filter structure, the simulator Ansoft Designer V2 was used. This software was also used for final optimization of the microstrip filter.
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