Slavko Rupčić - Academia.edu (original) (raw)
Papers by Slavko Rupčić
Sustainability, Jan 4, 2024
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Strojarstvo, Apr 30, 2010
Automated visual inspection Discrete wavelet transform Probabilistic neural network Quality contr... more Automated visual inspection Discrete wavelet transform Probabilistic neural network Quality control in tile production Ključne riječi Automatizirana vizualna provjera Diskretna valićna transformacija Kontrola kvalitete u proizvodnji pločica Probabilistička neuronska mreža
Zajednički temelji 2023. - uniSTem : deseti skup mladih istraživača iz područja građevinarstva i srodnih tehničkih znanosti, Split, 14.-17. rujna, 2023. : zbornik radova = Common Foundations 2023 - uniSTem : the tenth meeting of young researchers in the field of civil engineering and related tech...
In today's modern world, artificial sources of nonionizing electromagnetic radiation have bec... more In today's modern world, artificial sources of nonionizing electromagnetic radiation have become an indispensable part of our lives. The issue of potential health risks from exposure to this type of radiation remains a topic of discussion among scientists. In this paper, the influence of brick firing and the increase in humidity in solid bricks on the results of protection against EM radiation is analyzed at frequencies from 1.5 GHz to 6 GHz. Wet brick has the greatest ability to attenuate electromagnetic radiation, while drying and firing reduce this protection. Results showed that adding moisture to the material increased the electromagnetic shielding, while firing resulted in decreased shielding. The results are in agreement with the literature, where the electrical conductivity of the material is a key factor in electromagnetic protection. This work provides additional understanding of the influence of moisture and firing on the electromagnetic shielding of materials, which ...
The paper studies fabrication errors influence on the radiation pattern of a spherical antennas a... more The paper studies fabrication errors influence on the radiation pattern of a spherical antennas array. The developed Moment Method (MoM) program analyzes a particular influence of an azimuth and elevation position and local angle errors of antenna elements as well as model dimension errors on the radiation pattern. The spectral domain approach to the analysis of the spherical antenna arrays is applied here. Finally, results obtained from the theoretical investigation are verified by comparison with measured results.
Iet Microwaves Antennas & Propagation, Sep 19, 2017
This study presents an optimisation of antenna arrays on the spherical surface with new elementar... more This study presents an optimisation of antenna arrays on the spherical surface with new elementary antenna distribution using the particle swarm optimisation method. Many distributions of antenna elements on the sphere are known and processed, like icosahedral, spiral, Leopardi and so on, but neither of them is optimal. In this study, optimisation of the antenna array includes radiation pattern optimisation in order to achieve a radiation pattern with a narrow main lobe and very low side lobes. Although distribution of antenna elements is not uniform, optimisation is performed for two planes using the average fitness function. Different applications of antenna arrays require different parameters and different optimisation/process control procedures, too. Spherical antenna arrays with optimised placement of elements are capable of producing a desired radiation pattern, providing electronic scan coverage over the entire sphere and satisfying requirements for many applications in different branches of communications. An antenna array analysed in this study is a spherical array with very low grating lobes and a very narrow main lobe, and it could be used in hemispherical scan coverage.
ABSTRACT As power line communications show hostile properties for communication signal transmissi... more ABSTRACT As power line communications show hostile properties for communication signal transmission (noise, multi path propagation…) there is a need for a model that adequately describes noise phenomena in power line communication networks in order to speed up the development of PLC systems. This paper introduces a background and narrowband noise model based on measured data. The data measured was captured with a spectrum analyzer in the 0-20 MHz frequency range. Further the measured data are statistically processed and the results are used for a computer simulation model of background and narrowband noise.
Ovaj udžbenik sadrži upute za rad u laboratoriju te opis svih laboratorijskih vježbi iz kolegija ... more Ovaj udžbenik sadrži upute za rad u laboratoriju te opis svih laboratorijskih vježbi iz kolegija "Elektronicke komponente i osnovni sklopovi", a namijenjen je studentima VI. stupnja Elektrotehnickog Fakulteta u Osijeku. Cilj mu je olaksati rad u laboratoriju na mjerenjima i analizi rada elektronickih komponenata i osnovnih sklopova.
Springer eBooks, 2009
The main goals of Internet service providers are to maximize profit and maintain a negotiated qua... more The main goals of Internet service providers are to maximize profit and maintain a negotiated quality of service. However, achieving these objectives could become very complex if we know that Internet service users might during the session become highly ...
Automated visual inspection Discrete wavelet transform Probabilistic neural network Quality contr... more Automated visual inspection Discrete wavelet transform Probabilistic neural network Quality control in tile production Ključne riječi Automatizirana vizualna provjera Diskretna valićna transformacija Kontrola kvalitete u proizvodnji pločica Probabilistička neuronska mreža
The influence of model errors on radiation pattern of a hemispherical aperture antennas arrays is... more The influence of model errors on radiation pattern of a hemispherical aperture antennas arrays is studied in the paper. Analysis was made with a developed moment method program that analyzes a particular influence of an azimuth and elevation position and local angle errors of the second waveguide as well as model dimension errors on radiation pattern. The spectral-domain approach to the analysis of the spherical antenna arrays is presented in the paper. Theoretical free-space normalized radiation patterns of two waveguide antennas on the spherical surface with more details are analyzed in this paper. Assumed values of the theoretical model errors are in the range of expected real model errors.
This paper presents a significant sidelobe reduction if nonuniform elevational spacing of antenna... more This paper presents a significant sidelobe reduction if nonuniform elevational spacing of antenna elements on the sphere is used. Antenna elements are progressively phased with a uniform amplitude excitation. The calculation of the required element position is presented. The achieved sidelobe level reduction with unequally spaced arrays could reach even more than 20dB difference with regard to the first significant sidelobe level of equally spaced arrays. By this method, arrays have the ability to produce the desired radiation pattern and could satisfy requirements for many applications.
This paper is the result of calculating and measuring the reflection coefficient S11S_{11}S11 of an a... more This paper is the result of calculating and measuring the reflection coefficient S11S_{11}S11 of an aperture antenna fed by circular waveguide covered with dielectric material. These results help to better understand the influence of dielectrics on the aperture antenna reflection coefficients. Previous research has shown that proper dielectric radome selection can improve antenna impedance matching, and thus this paper deals with the influence of the modification in dielectric type and dielectric thickness on the coefficients of above mentioned antenna. Measurements and simulations showed good broadband impedance matching.
This paper considers the experimental shielding effectiveness analysis of an enclosure with a met... more This paper considers the experimental shielding effectiveness analysis of an enclosure with a metal plate placed at a certain angle inside. Dimensions of a metal plate are determined to affect the enclosure’s first resonant frequency in order to improve its protective function. A metal plate impact inside measured enclosure on the shielding effectiveness values especially at the first frequency as well as at the whole frequency range is presented.
2023 30th International Conference on Systems, Signals and Image Processing (IWSSIP)
Facta universitatis - series: Electronics and Energetics
In this paper, the impact of an electromagnetic absorber inside a protective metal enclosure is a... more In this paper, the impact of an electromagnetic absorber inside a protective metal enclosure is analyzed. The absorber is put inside the enclosure in order to improve its shielding effectiveness, especially at the first resonant frequency. Different absorber's sheet positions inside the enclosure are analyzed. The absorber sheet dimensions are fitted to correspond the enclosure's walls. The experimental procedure is conducted in a semi-anechoic room. The numerical TLM simulations of the EM filed distribution inside enclosure are conducted in order to consider position of the absorber sheet on different walls.
2020 International Conference on Smart Systems and Technologies (SST)
This paper describes the electromagnetic wave (EM) attenuation by concrete blocks focusing on the... more This paper describes the electromagnetic wave (EM) attenuation by concrete blocks focusing on the frequency range 1.70 – 1.88 GHz and 3.40 – 3.80 GHz. The attenuation calculation of concrete was made according to ITU recommendation ITU-R P.2040-1 (07/2015) for conducting dielectric. Also, the attenuation calculation was made using simulated values of S11 and S21 parameters. These two sets of computationally derived data were compared with each other, and the differences were not significant. The values of EM wave attenuation during propagation through concrete were compared with the values from the available literature and the deviations are also minor. 5G systems use higher frequencies and the tested concrete materials shield the 5G signals better than 4G signals. The results of this research can be used in the building walls with high attenuation for 4G and 5G communication systems.
Sustainability, Jan 4, 2024
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Strojarstvo, Apr 30, 2010
Automated visual inspection Discrete wavelet transform Probabilistic neural network Quality contr... more Automated visual inspection Discrete wavelet transform Probabilistic neural network Quality control in tile production Ključne riječi Automatizirana vizualna provjera Diskretna valićna transformacija Kontrola kvalitete u proizvodnji pločica Probabilistička neuronska mreža
Zajednički temelji 2023. - uniSTem : deseti skup mladih istraživača iz područja građevinarstva i srodnih tehničkih znanosti, Split, 14.-17. rujna, 2023. : zbornik radova = Common Foundations 2023 - uniSTem : the tenth meeting of young researchers in the field of civil engineering and related tech...
In today's modern world, artificial sources of nonionizing electromagnetic radiation have bec... more In today's modern world, artificial sources of nonionizing electromagnetic radiation have become an indispensable part of our lives. The issue of potential health risks from exposure to this type of radiation remains a topic of discussion among scientists. In this paper, the influence of brick firing and the increase in humidity in solid bricks on the results of protection against EM radiation is analyzed at frequencies from 1.5 GHz to 6 GHz. Wet brick has the greatest ability to attenuate electromagnetic radiation, while drying and firing reduce this protection. Results showed that adding moisture to the material increased the electromagnetic shielding, while firing resulted in decreased shielding. The results are in agreement with the literature, where the electrical conductivity of the material is a key factor in electromagnetic protection. This work provides additional understanding of the influence of moisture and firing on the electromagnetic shielding of materials, which ...
The paper studies fabrication errors influence on the radiation pattern of a spherical antennas a... more The paper studies fabrication errors influence on the radiation pattern of a spherical antennas array. The developed Moment Method (MoM) program analyzes a particular influence of an azimuth and elevation position and local angle errors of antenna elements as well as model dimension errors on the radiation pattern. The spectral domain approach to the analysis of the spherical antenna arrays is applied here. Finally, results obtained from the theoretical investigation are verified by comparison with measured results.
Iet Microwaves Antennas & Propagation, Sep 19, 2017
This study presents an optimisation of antenna arrays on the spherical surface with new elementar... more This study presents an optimisation of antenna arrays on the spherical surface with new elementary antenna distribution using the particle swarm optimisation method. Many distributions of antenna elements on the sphere are known and processed, like icosahedral, spiral, Leopardi and so on, but neither of them is optimal. In this study, optimisation of the antenna array includes radiation pattern optimisation in order to achieve a radiation pattern with a narrow main lobe and very low side lobes. Although distribution of antenna elements is not uniform, optimisation is performed for two planes using the average fitness function. Different applications of antenna arrays require different parameters and different optimisation/process control procedures, too. Spherical antenna arrays with optimised placement of elements are capable of producing a desired radiation pattern, providing electronic scan coverage over the entire sphere and satisfying requirements for many applications in different branches of communications. An antenna array analysed in this study is a spherical array with very low grating lobes and a very narrow main lobe, and it could be used in hemispherical scan coverage.
ABSTRACT As power line communications show hostile properties for communication signal transmissi... more ABSTRACT As power line communications show hostile properties for communication signal transmission (noise, multi path propagation…) there is a need for a model that adequately describes noise phenomena in power line communication networks in order to speed up the development of PLC systems. This paper introduces a background and narrowband noise model based on measured data. The data measured was captured with a spectrum analyzer in the 0-20 MHz frequency range. Further the measured data are statistically processed and the results are used for a computer simulation model of background and narrowband noise.
Ovaj udžbenik sadrži upute za rad u laboratoriju te opis svih laboratorijskih vježbi iz kolegija ... more Ovaj udžbenik sadrži upute za rad u laboratoriju te opis svih laboratorijskih vježbi iz kolegija "Elektronicke komponente i osnovni sklopovi", a namijenjen je studentima VI. stupnja Elektrotehnickog Fakulteta u Osijeku. Cilj mu je olaksati rad u laboratoriju na mjerenjima i analizi rada elektronickih komponenata i osnovnih sklopova.
Springer eBooks, 2009
The main goals of Internet service providers are to maximize profit and maintain a negotiated qua... more The main goals of Internet service providers are to maximize profit and maintain a negotiated quality of service. However, achieving these objectives could become very complex if we know that Internet service users might during the session become highly ...
Automated visual inspection Discrete wavelet transform Probabilistic neural network Quality contr... more Automated visual inspection Discrete wavelet transform Probabilistic neural network Quality control in tile production Ključne riječi Automatizirana vizualna provjera Diskretna valićna transformacija Kontrola kvalitete u proizvodnji pločica Probabilistička neuronska mreža
The influence of model errors on radiation pattern of a hemispherical aperture antennas arrays is... more The influence of model errors on radiation pattern of a hemispherical aperture antennas arrays is studied in the paper. Analysis was made with a developed moment method program that analyzes a particular influence of an azimuth and elevation position and local angle errors of the second waveguide as well as model dimension errors on radiation pattern. The spectral-domain approach to the analysis of the spherical antenna arrays is presented in the paper. Theoretical free-space normalized radiation patterns of two waveguide antennas on the spherical surface with more details are analyzed in this paper. Assumed values of the theoretical model errors are in the range of expected real model errors.
This paper presents a significant sidelobe reduction if nonuniform elevational spacing of antenna... more This paper presents a significant sidelobe reduction if nonuniform elevational spacing of antenna elements on the sphere is used. Antenna elements are progressively phased with a uniform amplitude excitation. The calculation of the required element position is presented. The achieved sidelobe level reduction with unequally spaced arrays could reach even more than 20dB difference with regard to the first significant sidelobe level of equally spaced arrays. By this method, arrays have the ability to produce the desired radiation pattern and could satisfy requirements for many applications.
This paper is the result of calculating and measuring the reflection coefficient S11S_{11}S11 of an a... more This paper is the result of calculating and measuring the reflection coefficient S11S_{11}S11 of an aperture antenna fed by circular waveguide covered with dielectric material. These results help to better understand the influence of dielectrics on the aperture antenna reflection coefficients. Previous research has shown that proper dielectric radome selection can improve antenna impedance matching, and thus this paper deals with the influence of the modification in dielectric type and dielectric thickness on the coefficients of above mentioned antenna. Measurements and simulations showed good broadband impedance matching.
This paper considers the experimental shielding effectiveness analysis of an enclosure with a met... more This paper considers the experimental shielding effectiveness analysis of an enclosure with a metal plate placed at a certain angle inside. Dimensions of a metal plate are determined to affect the enclosure’s first resonant frequency in order to improve its protective function. A metal plate impact inside measured enclosure on the shielding effectiveness values especially at the first frequency as well as at the whole frequency range is presented.
2023 30th International Conference on Systems, Signals and Image Processing (IWSSIP)
Facta universitatis - series: Electronics and Energetics
In this paper, the impact of an electromagnetic absorber inside a protective metal enclosure is a... more In this paper, the impact of an electromagnetic absorber inside a protective metal enclosure is analyzed. The absorber is put inside the enclosure in order to improve its shielding effectiveness, especially at the first resonant frequency. Different absorber's sheet positions inside the enclosure are analyzed. The absorber sheet dimensions are fitted to correspond the enclosure's walls. The experimental procedure is conducted in a semi-anechoic room. The numerical TLM simulations of the EM filed distribution inside enclosure are conducted in order to consider position of the absorber sheet on different walls.
2020 International Conference on Smart Systems and Technologies (SST)
This paper describes the electromagnetic wave (EM) attenuation by concrete blocks focusing on the... more This paper describes the electromagnetic wave (EM) attenuation by concrete blocks focusing on the frequency range 1.70 – 1.88 GHz and 3.40 – 3.80 GHz. The attenuation calculation of concrete was made according to ITU recommendation ITU-R P.2040-1 (07/2015) for conducting dielectric. Also, the attenuation calculation was made using simulated values of S11 and S21 parameters. These two sets of computationally derived data were compared with each other, and the differences were not significant. The values of EM wave attenuation during propagation through concrete were compared with the values from the available literature and the deviations are also minor. 5G systems use higher frequencies and the tested concrete materials shield the 5G signals better than 4G signals. The results of this research can be used in the building walls with high attenuation for 4G and 5G communication systems.