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Measurement of the optical intensity distribution at the far field
Vitásek, Jan ; Němeček, Jiří (referee) ; Wilfert, Otakar (advisor)
The topic of this master’s thesis is energy measurement of the optical intensity distribu-tion at the far field. Properties of the optical intensity and the optical power are described. In this thesis solution of wave equation is done. The plane wave, spherical wave and Gaussian beam are described. In this thesis, optical trace of laser beam from transmitter laser diode to receiver PIN photodiode is described. One of the solved problems is diffraction on the lens socket. The basic configuration for diffraction investigation on lens socket was created. There were transmitting laser diode, stop with circular apertures and PIN photodiode used in the experiment. In the other part, thesis deals with measuring and detection of the optical beam. Sorts of photodiodes and their characteristics were analysed.
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Reconfigurable multiband antenna
Havlín, Radomil ; Goňa, Stanislav (referee) ; Raida, Zbyněk (advisor)
This thesis deals with modeling and produce of reconfigurable multi-band planar antennas, which allow electrical shifting of frequency band. After antennas simulation with PIN diode and FET switch in a commercial program CST MW, another step is to optimize the antenna for a new substrate. The next step was to produce antennas. Finally, the optimized antennas are compared with the measurement on experimental antennas.
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PIN Modulator and Attenuator - laboratory experiments
Kaller, Ondřej ; Jakubová, Ivana (referee) ; Svačina, Jiří (advisor)
Purpose of this bachelor’s thesis is making conception of laboratory work “Amplitude modulator and attenuator with diode PIN“, what was alternative work measure in subject BSES on other sample. For this laboratory work was chosen amplitude modulator of company Hewlett Packard HP - 8732A for its advantage properties, especially easy manipulation with respect to coaxial connection of microwave signal. Work contains partly theoretical summary principles activity of diode PIN, partly it introduce their applications, especially in amplitude modulators directed of reflex reducer. Next there are documented results of single measures servant for ensure check needed properties modulator HP – 8732A. The main part of this work is proposal several points of measure together with introductions for operating devices, proposal form of measure protocol and it’s example. Final point is idea of possibility usage this modulator in power stabilizer.
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Microwave Modulators Based on Sixports
Dušek, Martin ; Bezoušek, Pavel (referee) ; Galajda, Pavol (referee) ; Šebesta, Jiří (advisor)
This doctoral thesis is focused on problems of modulators based on six-ports. It begins with description of current state of the art of six-ports used like modulators, their transfer functions and SIW technology. A design part of this thesis consists from experimental six-port based on substrate integrated waveguide (SIW) technology. There is presented step-by-step development of this six-port using this technology and also there is introduced micro-strip technology based six-port. Final design of six-ports and variable impedances were measured, the results are discussed and compared with expected ones in next chapters. Second part of this thesis deals with influences of internal parameters of six-ports to final signal transmission and derives theirs transfer functions for more than one reflection in structure. The computation results are compared with experimental measurements for fixed loads. With using of ideal loads sweeps, modulations with shaped input signals were calculated. For designed variables impedances, there was founded the optimal biasing points for demanded IQ diagram and discussed which from tested active circuit is suitable. In the last part there are shown results of experiment with these variable loads connected to both types of designed six-ports.
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Characterization of hydrogenated silicon thin films and diode structures with integrated silicon and germanium nanoparticles
Stuchlík, Jiří ; Fajgar, R. ; Remeš, Zdeněk ; Kupčík, Jaroslav ; Stuchlíková, Hana
P-I-N diode structures based on the thin films of amorphous hydrogenated silicon (a-Si:H) deposited by Plasma Enhanced Chemical Vapor Deposition (PECVD) technique were prepared with embedded Si and Ge nanoparticles. The Reactive Laser Ablation (RLA) of germanium target was used to cover the intrinsic a-Si:H layer by Ge NPs under a low pressure of the silane. The RLA was performed using focused excimer ArF laser beam under SiH4 background atmosphere. Reaction between ablated Ge NPs and SiH4 led to formation of Ge NPs covered by thin GeSi:H layer. The deposited NPs were covered and stabilized by a-Si:H layer by PECVD. Those two deposition processes were alternated repeatedly. Volt-ampere characteristics of final diode structures were measured in dark and under illumination as well as their electroluminescence spectra.
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Characterization of hydrogenated silicon thin films and diode structures with integrated germanium nanoparticles
Stuchlík, J. ; Fajgar, R. ; Remeš, Z. ; Kupčík, Jaroslav ; Stuchlíková, H.
P-I-N diode structures based on the thin films of amorphous hydrogenated silicon (a-Si: H) deposited by Plasma Enhanced Chemical Vapor Deposition (PECVD) technique were prepared with embedded Si and Ge nanoparticles. The Reactive Laser Ablation (RLA) of germanium target was used to cover the intrinsic a-Si: H layer by Ge NPs under a low pressure of the silane. The RLA was performed using focused excimer ArF laser beam under SiH4 background atmosphere. Reaction between ablated Ge NPs and SiH4 led to formation of Ge NPs covered by thin GeSi: H layer. The deposited NPs were covered and stabilized by a-Si: H layer by PECVD. Those two deposition processes were alternated repeatedly. Volt-ampere characteristics of final diode structures were measured in dark and under illumination as well as their electroluminescence spectra.
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Microwave Modulators Based on Sixports
Dušek, Martin ; Bezoušek, Pavel (referee) ; Galajda, Pavol (referee) ; Šebesta, Jiří (advisor)
This doctoral thesis is focused on problems of modulators based on six-ports. It begins with description of current state of the art of six-ports used like modulators, their transfer functions and SIW technology. A design part of this thesis consists from experimental six-port based on substrate integrated waveguide (SIW) technology. There is presented step-by-step development of this six-port using this technology and also there is introduced micro-strip technology based six-port. Final design of six-ports and variable impedances were measured, the results are discussed and compared with expected ones in next chapters. Second part of this thesis deals with influences of internal parameters of six-ports to final signal transmission and derives theirs transfer functions for more than one reflection in structure. The computation results are compared with experimental measurements for fixed loads. With using of ideal loads sweeps, modulations with shaped input signals were calculated. For designed variables impedances, there was founded the optimal biasing points for demanded IQ diagram and discussed which from tested active circuit is suitable. In the last part there are shown results of experiment with these variable loads connected to both types of designed six-ports.
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|
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PIN Modulator and Attenuator - laboratory experiments
Kaller, Ondřej ; Jakubová, Ivana (referee) ; Svačina, Jiří (advisor)
Purpose of this bachelor’s thesis is making conception of laboratory work “Amplitude modulator and attenuator with diode PIN“, what was alternative work measure in subject BSES on other sample. For this laboratory work was chosen amplitude modulator of company Hewlett Packard HP - 8732A for its advantage properties, especially easy manipulation with respect to coaxial connection of microwave signal. Work contains partly theoretical summary principles activity of diode PIN, partly it introduce their applications, especially in amplitude modulators directed of reflex reducer. Next there are documented results of single measures servant for ensure check needed properties modulator HP – 8732A. The main part of this work is proposal several points of measure together with introductions for operating devices, proposal form of measure protocol and it’s example. Final point is idea of possibility usage this modulator in power stabilizer.
|
|
|
Reconfigurable multiband antenna
Havlín, Radomil ; Goňa, Stanislav (referee) ; Raida, Zbyněk (advisor)
This thesis deals with modeling and produce of reconfigurable multi-band planar antennas, which allow electrical shifting of frequency band. After antennas simulation with PIN diode and FET switch in a commercial program CST MW, another step is to optimize the antenna for a new substrate. The next step was to produce antennas. Finally, the optimized antennas are compared with the measurement on experimental antennas.
|
|
|
Measurement of the optical intensity distribution at the far field
Vitásek, Jan ; Němeček, Jiří (referee) ; Wilfert, Otakar (advisor)
The topic of this master’s thesis is energy measurement of the optical intensity distribu-tion at the far field. Properties of the optical intensity and the optical power are described. In this thesis solution of wave equation is done. The plane wave, spherical wave and Gaussian beam are described. In this thesis, optical trace of laser beam from transmitter laser diode to receiver PIN photodiode is described. One of the solved problems is diffraction on the lens socket. The basic configuration for diffraction investigation on lens socket was created. There were transmitting laser diode, stop with circular apertures and PIN photodiode used in the experiment. In the other part, thesis deals with measuring and detection of the optical beam. Sorts of photodiodes and their characteristics were analysed.
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