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Frequency synthesizer for microwave communication systems
Klapil, Filip ; Vondra, Vlastimil (referee) ; Kasal, Miroslav (advisor)
The main aim of the thesis is to develop a solution of a frequency synthesizer for a microwave communication systems. Specifically, it suggests a design for frequency synthesizer with phase-locked loop. At beginning of the thesis the principle and basic properties of this method of signal generation are explained. Then it is followed by a brief discussion of the parameters of synthesizers and their influence on design. Another part of the work is the analysis of circuit the frequency synthesizer with the phase-locked loop MAX2871, which is followed by a proposal for the design of the frequency synthesizer module hardware. The last part of the work deals with practical implementation, verification of function and measurement of achieved parameters and their evaluation.
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UHF band front-end of quadrature receiver
Tiller, Jakub ; Špaček, Jiří (referee) ; Kasal, Miroslav (advisor)
The object of this master's thessis is study and description of RF circuits, which are used for receiveing. This work is also aimed to design this circuits and their simulation in Ansoft Designer software. Focus is placed to the standard parameters of receiving technology. The description of amplifier design is presented in this work. Parameters of this amplifier are optimalized to low noise figure. Frequency multiplier designs are included in this project.
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Antenna for microwave beacon on X-band
Zamazal, Bořivoj ; Pokorný, Michal (referee) ; Kasal, Miroslav (advisor)
This bachelor’s thesis describes an antenna design for microwave beacon in 10 GHz band. In the first section of the work, the possible solutions are presented and a slot antenna, constructed from commercially available waveguide, is chosen. In the second section, the principle of this antenna is described and the dimensions for the chosen frequency and the type of waveguide are calculated. In the third section, the antenna model is built and simulated in the Ansof HFSS environment in accordance with theoretically calculated dimensions and, based on these simulations, two possible versions of antenna are created.
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Direct digital frequency synthesizer
Svoboda, Josef ; Šebesta, Jiří (referee) ; Kasal, Miroslav (advisor)
Direct Digital Frequency Synthesis (DDFS) is a method of producing an analog waveform, usually a sine wave, by generating a time varying signal in digital form a then performing a digital to analog conversion. Because operations within a DDFS device are primarily digital, it can offer fast switching between output frequencies, fine frequency resolution and operation over a broad spectrum of frequencies.
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Modulation signal source for microwave beacon
Belloň, Michal ; Vondra, Vlastimil (referee) ; Kasal, Miroslav (advisor)
This project is focused on construction of source of modulation signal for microwave beacon. The output signal is the same as signal, which is generated by PC software WSJT (Weak Signal by Joe Taylor) on PC sound card output. Signal on device output is modulated using by WSJT modulation and its specific JT4 mode. The device output has I and Q components of signal.
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L-band receiver front-end
Kolář, Jan ; Špaček, Jiří (referee) ; Kasal, Miroslav (advisor)
This Master's Thesis deals with a design of L-band receiver front-end. In the concrete the receiver is designed for receiving signals of frequency band 1,3 GHz. All particular blocks from low noise amplifier to intermediate frequency amplifier and frequency doubler in LO input are described, designed and simulated in program Ansoft. The part of this Master's Thesis is aimed to construct a working front-end receiver and to measure its basic parameters.
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GPS Two-Stage Low Noise Amplifier
Šindler, Pavel ; Kasal, Miroslav (referee) ; Baran, Ondřej (advisor)
This work deals with a design of a low noise amplifier for the GPS band. The first part shortly describes properties of GPS signals and possible jamming sources. In the next chapter, basic parameters of low noise amplifiers, ways of the amplifier stability determination and stabilization are described. A summary of methods of a narrowband amplifier design follows. The next chapter contains a short description of filters usable in the designed amplifier. The next part deals with the design of the two-stage low noise amplifier with the help of Ansoft Designer software. The following part deals with the amplifier realization and its parameters measuring. At the end of this work, some experience with GPS signals reception with the realized low noise amplifier, a passive antenna and two different types of GPS receivers are mentioned.
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Low-noise S-band amplifier
Potěšil, Dušan ; Vágner, Petr (referee) ; Kasal, Miroslav (advisor)
This work deals with design, simulation and realisation of a receiving systém of an S-band front end for satellite communication. The first part of the project is designed the low noise amplifier (LNA) with high associated gain. The basic point of the design is choice of the active device. In the present time are available the ultra low noise transistors based on the GaAs with high mobility electron. The two-stage LNA has been designed with Agilent ATF-55143. It is pseudomorphic HEMTs ,which work in an enhancement mode.These transistor do not require a negative bias voltage and have extremely good typical noise figure. The design includes an interdigital tuned band pass filter between stages. The second part of the project is search another way design circuit. There are designed two LNA with paralel coupled line filter. The first has been applied on a PTFE substrate Duroid 5880 with relative permitivity 2,2 and tg d = 0,009. The substrate FR-4 (r = 4.34) with the thickness 0.06” was used for the realization.
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