|
|
SIW-Based Circularly Polarized Antenna Arrays
Špůrek, Jan ; Joler,, Miroslav (oponent) ; Mazánek, Miloš (oponent) ; Raida, Zbyněk (vedoucí práce)
This dissertation thesis presents a new concept of SIW-based circularly polarized antenna arrays. The main property of the concept is modularity where the base building block can be utilized to create more complex antenna arrays and at the same time it serves also as the template to design the more complex structure. The antenna array was simulated and experimentally verified for the frequencies of 17 and 60 GHz. Based on the obtained results, design methodology was derived, and key design areas were identified. Next, the thesis introduces a technique of increasing axial ratio bandwidth of circularly polarized antenna arrays by utilizing parasitic patches, which are placed above the radiating elements at defined distance. The antenna array from the first section of the thesis was used in the simulations and experimental verification for the frequencies of 17 and 60 GHz, where this array was extended with the parasitic structure, adding another level of modularity into the concept.
|
|
|
Electronic Components in Textile Substrates
Kokolia, Martin ; Joler,, Miroslav (oponent) ; Dražan, Libor (oponent) ; Raida, Zbyněk (vedoucí práce)
Goal of this thesis is to describe state of the art in the field of textile-based microwave components and then also author's contribution to research. There are many problems to solve in this field of study and thus very specific goals are stated that should form complete communication system that would be easily integrable into upholstery inside airplane or other vehicle. First chapter is aimed on the relatively low frequency UHF circuit application and the RF energy harvester. The simulations are followed by practical measurements. Next chapter is characterizing the novel 3D-knitted fabrics and their RF proprieties modeling on very high frequencies that are desired to be used as communication channels. With textile substrate validated and described for use at SHF band novel textile integrated waveguide base on printable artificial magnetic conductor structure is presented with practical methodology of design. After validation, the waveguide was utilized for basic power divider, two different antennas and two types of sensors. All designs were manufactured and tested with satisfactory results.
|
|
|
Textile Integrated Waveguide Components
Cupal, Miroslav ; Polívka, Milan (oponent) ; Joler, Miroslav (oponent) ; Raida, Zbyněk (vedoucí práce)
The thesis is focused on the research of structures based on the Textile Integrated Waveguide (TIW). Attention is turned to the electrical characterization of textile materials (textile substrates, yarns) to be used for the implementation of textile-integrated antennas, reconfigurable and active circuits. The thesis deals with the design of multilayer transitions between a microstrip line on a conventional substrate and textile-integrated lines. Second, a concept of the textile-integrated switch is presented. The switch is controlled by conductive posts which are connected or disconnected by DC driven PIN diodes to form open or closed walls. Finally, the design methodology for textile-integrated circularly polarized antennas operating in ISM bands up to 24 GHz is proposed. All the design procedures were verified by simulations and measurements of real samples manufactured by screen-printing using a silver polymer paste. For bonding semiconductor components, conductive silver adhesives were used. Screen-printed components were compared with reference structures manufactured from a self-adhesive copper foil.
|
|
|
Terahertz Antenna Arrays for Communications
Warmowska, Dominika ; Joler, Miroslav (oponent) ; Pokorný, Michal (oponent) ; Raida, Zbyněk (vedoucí práce)
The thesis is focused on the research of THz antenna arrays to be used for communications. Attention is turned to modeling metallic surfaces at THz frequencies, a proper characterization of gold conductivity, its relation to Drude model and corresponding measurements. Moreover, the best methods for modeling thin metallic layers (depending on the skin depth related to the metal thickness) are presented. An optimized element of a THz 2×2 antenna array designed for the application of communications is developed in a way that enables an expansion to a larger array. The expansion ability is demonstrated on a 4×4 antenna array which is presented in the thesis too. The designed antennas achieve parameters better than the state-of-art antennas. The presented antennas radiate circularly polarized wave at THz frequencies, operate in a wide bandwidth, have a high gain and are of a compact size. In the thesis, an 8×8 antenna array with a beam steering capability is presented. The main beam of the antenna array can be controlled in two dimensions. A high gain of the radiated circularly-polarized wave can be achieved that way. Different approaches to modeling antennas with thin metallic layers are compared and the best methods are recommended from the viewpoint of different requirements. The designed 2×2 and 4×4 antenna arrays are manufactured using a microfabrication technology. Each step of the fabrication is described in detail and discussed. The reflection coefficient at the input of antennas is measured and compared with simulations. Discrepancies in results are associated with surface roughness which is analyzed by a scanning probe microscope and a scanning electron microscope. By down-scaling the developed THz antenna, a low-profile high-gain antenna for Ka-band space applications is designed. The presented antenna achieves better results than state-of-art CubeSat antennas. The antenna performance is verified by a prototype to be operated at 9 GHz, and the radiation characteristics are experimentally confirmed.
|
|
|
SIW-Based Circularly Polarized Antenna Arrays
Špůrek, Jan ; Joler,, Miroslav (oponent) ; Mazánek, Miloš (oponent) ; Raida, Zbyněk (vedoucí práce)
This dissertation thesis presents a new concept of SIW-based circularly polarized antenna arrays. The main property of the concept is modularity where the base building block can be utilized to create more complex antenna arrays and at the same time it serves also as the template to design the more complex structure. The antenna array was simulated and experimentally verified for the frequencies of 17 and 60 GHz. Based on the obtained results, design methodology was derived, and key design areas were identified. Next, the thesis introduces a technique of increasing axial ratio bandwidth of circularly polarized antenna arrays by utilizing parasitic patches, which are placed above the radiating elements at defined distance. The antenna array from the first section of the thesis was used in the simulations and experimental verification for the frequencies of 17 and 60 GHz, where this array was extended with the parasitic structure, adding another level of modularity into the concept.
|
|
|
Electronic Components in Textile Substrates
Kokolia, Martin ; Joler,, Miroslav (oponent) ; Dražan, Libor (oponent) ; Raida, Zbyněk (vedoucí práce)
Goal of this thesis is to describe state of the art in the field of textile-based microwave components and then also author's contribution to research. There are many problems to solve in this field of study and thus very specific goals are stated that should form complete communication system that would be easily integrable into upholstery inside airplane or other vehicle. First chapter is aimed on the relatively low frequency UHF circuit application and the RF energy harvester. The simulations are followed by practical measurements. Next chapter is characterizing the novel 3D-knitted fabrics and their RF proprieties modeling on very high frequencies that are desired to be used as communication channels. With textile substrate validated and described for use at SHF band novel textile integrated waveguide base on printable artificial magnetic conductor structure is presented with practical methodology of design. After validation, the waveguide was utilized for basic power divider, two different antennas and two types of sensors. All designs were manufactured and tested with satisfactory results.
|
|
|
Terahertz Antenna Arrays for Communications
Warmowska, Dominika ; Joler, Miroslav (oponent) ; Pokorný, Michal (oponent) ; Raida, Zbyněk (vedoucí práce)
The thesis is focused on the research of THz antenna arrays to be used for communications. Attention is turned to modeling metallic surfaces at THz frequencies, a proper characterization of gold conductivity, its relation to Drude model and corresponding measurements. Moreover, the best methods for modeling thin metallic layers (depending on the skin depth related to the metal thickness) are presented. An optimized element of a THz 2×2 antenna array designed for the application of communications is developed in a way that enables an expansion to a larger array. The expansion ability is demonstrated on a 4×4 antenna array which is presented in the thesis too. The designed antennas achieve parameters better than the state-of-art antennas. The presented antennas radiate circularly polarized wave at THz frequencies, operate in a wide bandwidth, have a high gain and are of a compact size. In the thesis, an 8×8 antenna array with a beam steering capability is presented. The main beam of the antenna array can be controlled in two dimensions. A high gain of the radiated circularly-polarized wave can be achieved that way. Different approaches to modeling antennas with thin metallic layers are compared and the best methods are recommended from the viewpoint of different requirements. The designed 2×2 and 4×4 antenna arrays are manufactured using a microfabrication technology. Each step of the fabrication is described in detail and discussed. The reflection coefficient at the input of antennas is measured and compared with simulations. Discrepancies in results are associated with surface roughness which is analyzed by a scanning probe microscope and a scanning electron microscope. By down-scaling the developed THz antenna, a low-profile high-gain antenna for Ka-band space applications is designed. The presented antenna achieves better results than state-of-art CubeSat antennas. The antenna performance is verified by a prototype to be operated at 9 GHz, and the radiation characteristics are experimentally confirmed.
|
|
|
Textile Integrated Waveguide Components
Cupal, Miroslav ; Polívka, Milan (oponent) ; Joler, Miroslav (oponent) ; Raida, Zbyněk (vedoucí práce)
The thesis is focused on the research of structures based on the Textile Integrated Waveguide (TIW). Attention is turned to the electrical characterization of textile materials (textile substrates, yarns) to be used for the implementation of textile-integrated antennas, reconfigurable and active circuits. The thesis deals with the design of multilayer transitions between a microstrip line on a conventional substrate and textile-integrated lines. Second, a concept of the textile-integrated switch is presented. The switch is controlled by conductive posts which are connected or disconnected by DC driven PIN diodes to form open or closed walls. Finally, the design methodology for textile-integrated circularly polarized antennas operating in ISM bands up to 24 GHz is proposed. All the design procedures were verified by simulations and measurements of real samples manufactured by screen-printing using a silver polymer paste. For bonding semiconductor components, conductive silver adhesives were used. Screen-printed components were compared with reference structures manufactured from a self-adhesive copper foil.
|
host ::
RSS.