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Cascade Sierpinski monopole
Kadlček, Jiří ; Tkadlec, Roman (referee) ; Všetula, Petr (advisor)
This master’s thesis describes the theoretical analysis of the Sierpinski triangle structure. On the basis of this structure, a planar version of the Sierpinski monopole is firstly designed. Then, by using a transfer of the planar motive to the conical surface, conical and cascade Sierpinski monopoles are designed. All simulations are calculated by CST Microwave Studio 2011. In the thesis, four types of cascade Sierpinski monopole are proposed. The investigated parameters are reflection coefficient, input impedance, radiation properties, polarization and bandwidth. The attention is primarily focused on the design and experimental verification of the selected conical shape cascade Sierpinski monopole set on the bands GSM 900, GSM 1800 and Wi-fi 2,4 GHz.
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Wideband planar antennas
Špatenka, Vojtěch ; Tkadlec, Roman (referee) ; Wolanský, David (advisor)
In this master´s thesis an issue of broadband planar antennas was analyzed. Firstly, the basic elements that affect bandwidth, such as the influence of the dieletric substrate, suitable shape or feeding network, were described. Furthermore technics that can be used to widen the band of the planar antennas were described. These technics were applied to a chosen type of a planar antenna. This antenna was modeled and simulated for desired dielectric substrate in CST STUDIO SUITE 2010 software. Feeding network with power dividers was designed for the antenna array. In order to obtain a higher gain, the antenna was implemented into the 2x2 element array. The results of the simulation are evaluated in the conclusion.
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Design of diplexer based on coaxial resonators
Štěpánek, Michal ; Tkadlec, Roman (referee) ; Wolanský, David (advisor)
This thesis deals with the analysis of coaxial cavity filters and synthesis of generic topology of these filters. Transfer function comes out the synthesis, which is based on low-pass prototype and similarity with real structure. The next aim of this thesis is to build the basic software for coaxial cavity filters synthesis from engaged characteristic parameters of the filter. This work also includes the analysis of coupling matrix synthesis based on transfer function, where we can use direct coupling or cross-coupling between resonators. The last point is focused on the diplexer filter based on specified parameters and obtained coupling matrix. Entire diplexer model is optimized using Tuning-Space Mapping method.
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Circularly polarized serial antenna array
Hurt, Martin ; Tkadlec, Roman (referee) ; Kufa, Martin (advisor)
This work focuses on the design circularly polarized serial antennas array operate in the ISM band (5.725 GHz to 5.875 GHz). Design of antennas is divided into three parts. In the first part is designed feeding system, followed by two types of circularly polarized antennas and at the last point, these components are integrated. Furthermore, these antennas are fabricated, measured their parameters and used for experimental verification of the influence of multipath transmission in-vehicle.
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Design of dualband antenna for WiFi USB Dongle
Prchal, Lukáš ; Tkadlec, Roman (referee) ; Wolanský, David (advisor)
This project deals with the design of dual band antenna for the receiving of Wi-Fi signal integrated to the USB key receiver, which can be connected to notebook or PC with the help of interface and receive available Wi-fi signal . The center frequencies were chosen for 2,4 GHz and 5 GHz where the Wi-Fi signal operates and for these frequencies the antenna has been tuned. The antenna has been designed and simulated in CST Microwave Studio 2010. The first part of this work deals with the design of dual band antenna. Next, the resonant frequencies of the antenna are optimized in order to compensate the influence of the plastic housing and the electronic part of the USB key.
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Circularly polarized serial antenna array
Hurt, Martin ; Tkadlec, Roman (referee) ; Kufa, Martin (advisor)
This work focuses on the design circularly polarized serial antennas array operate in the ISM band (5.725 GHz to 5.875 GHz). Design of antennas is divided into three parts. In the first part is designed feeding system, followed by two types of circularly polarized antennas and at the last point, these components are integrated. Furthermore, these antennas are fabricated, measured their parameters and used for experimental verification of the influence of multipath transmission in-vehicle.
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Cascade Sierpinski monopole
Kadlček, Jiří ; Tkadlec, Roman (referee) ; Všetula, Petr (advisor)
This master’s thesis describes the theoretical analysis of the Sierpinski triangle structure. On the basis of this structure, a planar version of the Sierpinski monopole is firstly designed. Then, by using a transfer of the planar motive to the conical surface, conical and cascade Sierpinski monopoles are designed. All simulations are calculated by CST Microwave Studio 2011. In the thesis, four types of cascade Sierpinski monopole are proposed. The investigated parameters are reflection coefficient, input impedance, radiation properties, polarization and bandwidth. The attention is primarily focused on the design and experimental verification of the selected conical shape cascade Sierpinski monopole set on the bands GSM 900, GSM 1800 and Wi-fi 2,4 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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Design of diplexer based on coaxial resonators
Štěpánek, Michal ; Tkadlec, Roman (referee) ; Wolanský, David (advisor)
This thesis deals with the analysis of coaxial cavity filters and synthesis of generic topology of these filters. Transfer function comes out the synthesis, which is based on low-pass prototype and similarity with real structure. The next aim of this thesis is to build the basic software for coaxial cavity filters synthesis from engaged characteristic parameters of the filter. This work also includes the analysis of coupling matrix synthesis based on transfer function, where we can use direct coupling or cross-coupling between resonators. The last point is focused on the diplexer filter based on specified parameters and obtained coupling matrix. Entire diplexer model is optimized using Tuning-Space Mapping method.
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