|
|
Measuring antenna for 1 - 6 GHz band
Slažanský, Libor ; Lukeš, Zbyněk (referee) ; Nováček, Zdeněk (advisor)
The thesis is focused on the design of a measuring antenna for 1 – 6 GHz band. It deals with the types of log periodic antennas with the the detailed elaboration of log periodic dipole antennas (LPDA). One can find the description of their functions, maximum features and the possibilities to use the asymmetrical feeder. Also there is the procedure of LPDA design and the realization of the design itself including simulation in 4NEC2 programme. In the next part there is a planar LPDA realization with the microstrip-to-balanced stripline balun symmetrization. This design was simulated and tested within the frames of Zeland IE3D programme. The last part contains the measuring results of S parametres as well as beam characteristics of the planar version of LPDA.
|
|
|
Measurement of antenna radiation pattern
Drdla, Karel ; Dřínovský, Jiří (referee) ; Nováček, Zdeněk (advisor)
The aim of my diploma thesis is to produce an automated workplace for an antenna radiation pattern measurement with the R&S ESCS 30 measurement device. The result is a program named SFMAP.EXE. The measurement process is controlled by this program according to user defined parameters. The program collects the R&S ESCS 30 measured values and can evaluate the radiation angle values of the antenna. It can set up some parameters of the measurement device and controls the rotation of the turn-table, where the measured antenna is positioned. The controlling device based on FT232BL circuit was developed to capacitate the program to control the turn-table. With created program the turn-table can be controlled over the USB interface. This solution allows using any PC or notebook because of its standard equipment - the USB interface.
|
|
|
Automatization of EM field measurement by Narda NBM-550
Kopecký, Petr ; Bártík, Hynek (referee) ; Nováček, Zdeněk (advisor)
The diploma thesis deals with the measurement of electromagnetic fields by the meter NARDA NBM 550. The aim of the paper is to introduce the possibilities of measurement of the electromagnetic field by this device, to study the feasibility of communication with computer, to create control program and to check its functionality. A description of the electromagnetic field properties is followed by the identification of the device main functions. Additionally, the operating program is described together with the draft of measuring workplace with its realization. The results of probationary measurements are presented in the end of the thesis.
|
|
|
Measurement of the near field distribution
Macháček, Ivan ; Tkadlec, Roman (referee) ; Nováček, Zdeněk (advisor)
The aim of this work was to prepare measuring workplace, perform the verication measurement, including the measurement phase, on the cylindrical surface. Measured data were compared with theoretical assumptions and were calculated directional patterns. Probes for measurement in the near sield were designed and realized.
|
|
|
Computer design of a digital radio link
Havel, Ladislav ; Nováček, Zdeněk (referee) ; Láčík, Jaroslav (advisor)
The Terrestrial digital radio links are used for transmitting digital information between fixed stations on a line of sight of a radio path. Each digital radio link has many characteristics and parameters for transmission. We require technical parameters in the design of digital radio link such as data rates and capacities. In this design we should take into account most effects of the electromagnetic waves propagation, if we want to meet user technical requirements of the link and if that link may correctly transmit digital signals with minimum errors. Prediction methods for the design of terrestrial line of sight systems are still in progress. Some effects of electromagnetic waves propagation and methods of the digital radio link design depend on natural variability and climate. The goal of this diploma thesis is to investigate methods for the design of terrestrial line of sight links with taking into account of ITU recommendation. Make computer program which implement this investigate methods
|
|
|
Design of log-periodic antenna
Kliha, Marek ; Nováček, Zdeněk (referee) ; Láčík, Jaroslav (advisor)
This diploma thesis deal with the design of log-periodic antenna. The log-periodic antenna is self-complementary and broadband antenna. Antenna self-complementary structures are described only by angles. Input impedance of log-periodic antenna is equal to theoretical impedance ohms. The input impedance and radiation patterns of broadband antenna structures are independent of frequency over theoretically unlimited bandwidths. The log-periodic antennas provide linearly polarized radiation pattern. In this thesis is designed antenna for bandwidths 1 to 5GHz. In this diploma thesis is introduced design balanced unit, this is compound broadband balun and broadband impedance transformer. The broadband balun is based on conversion of microstrip line to balanced stripline. The Klopfenstein impedance taper is used for design. For simulation was used software from firma Zeland software IE3D.
|
|
|
Current distribution on linear antennas
Novák, Tomáš ; Bártík, Hynek (referee) ; Nováček, Zdeněk (advisor)
This work will describe current distribution measurement problems along antenna conductor using a probe (coupling loop), which is attached to selective micro-voltmeter, which will indicate signal level (voltage). The signal level will be used for representing the current distribution. Subsequently, measuring workplace issues from generator to antenna conductor, probe and selective micro-voltmeter, will be discussed. Analysis of voltages of this link-up and additional study will be conducted. Other parameters, which complement this situation, will be calculated from the current distribution. A computer program, which calculates these parameters and speeds up the collected data processing, will be used for this process.
|
|
|
Reconstruction of the Antenna Near-Field
Puskely, Jan ; Mazánek, Miloš (referee) ; Schejbal, Vladimír (referee) ; Nováček, Zdeněk (advisor)
Cílem disertační práce je navrhnout efektivně pracující algoritmus, který na základě bezfázového měření v blízkém poli antény bude schopen zrekonstruovat komplexní blízké pole antény resp. vyzařovací diagram antény ve vzdáleném poli. Na základě těchto úvah byly zkoumány vlastnosti minimalizačního algoritmu. Zejména byl analyzován a vhodně zvolen minimalizační přistup, optimalizační metoda a v neposlední řadě i optimalizační funkce tzv. funkcionál. Dále pro urychlení celého minimalizačního procesu byly uvažovány prvotní odhady. A na závěr byla do minimalizačního algoritmu zahrnuta myšlenka nahrazující hledané elektrické pole několika koeficienty. Na základě předchozích analýz byla navržená bezfázová metoda pro charakterizaci vyzařovacích vlastností antén. Tato metoda kombinuje globální optimalizaci s obrazovou kompresní metodou a s lokální metodou ve spojení s konvečním amplitudovým měřením na dvou površích. V našem případě je globální optimalizace použita k nalezení globálního minima minimalizovaného funkcionálu, kompresní metoda k redukci neznámých proměnných na apertuře antény a lokální metoda zajišťuje přesnější nalezení minima. Navržená metoda je velmi robustní a mnohem rychlejší než jiné dostupné minimalizační algoritmy. Další výzkum byl zaměřen na možnosti využití měřených amplitud pouze z jednoho měřícího povrchu pro rekonstrukci vyzařovacích charakteristik antén a využití nového algoritmu pro rekonstrukci fáze na válcové geometrii.
|
|
|
Radiation of antenna array in near-field area
Hermany, Jiří ; Láčík, Jaroslav (referee) ; Nováček, Zdeněk (advisor)
The aim of my diploma thesis is to analyze the antenna array radiation and to produce the antenna array radiation computation program. The program should display the electric and magnetic intensity and radiation power density distribution over the planar or cylindrical surface in the near-field area. The antenna array analyzed in this paper consists of a number of elementary dipoles placed in a row with a reflector which represents the conductive board situated in parallel to the row of dipoles. The demonstration program was built in MATLAB and allows computing and displaying the computed values components of antenna array radiation on the planar or the cylindrical surface. The program also allows saving computed values, saving displayed graphs, or saving the adjusted parameters of antenna array. The created program can be used for the presentation of the antenna array radiation in a school laboratory or for the graphical representation when a new antenna is designed.
|
|
|
Current distribution on linear antennas
Dvořák, Zdeněk ; Puskely, Jan (referee) ; Nováček, Zdeněk (advisor)
Bachelor’s thesis of Current distribution on linear antennas is concerned about possibilities of measuring current distribution on antenna. There is also close peak on measuring principles with help of measuring loop. Current in the loop is inducted in continual proportion to magnetic induction, which is inducted by the current distributed on antenna conductor in proximity of measuring loop. There are also described important parameters of antenna, which can be got from current distribution. This thesis discusses about the method of measure with the sonde in more detail. The expanded program DISTRIB helps to process measured values. This program is modified specially for short and long antennas. There is enclosed the projected submission of laboratory exercise, an exemplary protocol and sinusoidal regression calculation, which is used by the computer program.
|
guest ::
