A. Stanislavsky, A. Koval, I. Bubnov, A. Brazhenko
Subject and Purpose. Results are presented of the solar corona investigations performed with the world famous Ukrainian radio telescopes. The work has been aimed at offering a consistent review of recent achievements in observations of a variety of low-frequency radio emissions from the Sun. Methods and Methodology. The studies of the quiet (thermal) and sporadic (burst-like) radio emissions from the Sun have been car- ried out with the decameter-wavelength radio telescopes UTR-2, GURT and URAN-2. Specific features of the low-frequency solar radio emissions from a variety of sources are presented, with characterization of the optimized techniques that were applied in each case for evaluating physical parameters of the corona in the areas of decameter-wavelength radio wave generation. Results. The analysis of temporal, frequency and spatial characteristics of solar radio emissions has allowed suggesting a number of models for the coronal electron density distribution, and evaluating magnetic field strengths in the corona. Also, our experimental results have proven to be consistent with the observational data obtained in different frequency ranges and with the use of both ground based and space-borne instruments. Conclusions. The radio observations performed with Ukrainian radio telescopes have permitted studying, with high temporal, fre- quency and spatial resolutions, solar radio frequency emissions from various localized sources. Along with the large effective area and high sensitivity of the antennas, this permits application of a wide range of methods and tools aimed at detecting and analyzing solar bursts, of both strong and weak intensity, against the background of terrestrial interference of natural or artificial origin
{"title":"PROGRESS IN THE STUDY OF DECAMETER-WAVELENGTH SOLAR RADIO EMISSION WITH UKRAINIAN RADIO TELESCOPES. Part 1. (Invited paper)","authors":"A. Stanislavsky, A. Koval, I. Bubnov, A. Brazhenko","doi":"10.15407/rpra28.02.095","DOIUrl":"https://doi.org/10.15407/rpra28.02.095","url":null,"abstract":"Subject and Purpose. Results are presented of the solar corona investigations performed with the world famous Ukrainian radio telescopes. The work has been aimed at offering a consistent review of recent achievements in observations of a variety of low-frequency radio emissions from the Sun. Methods and Methodology. The studies of the quiet (thermal) and sporadic (burst-like) radio emissions from the Sun have been car- ried out with the decameter-wavelength radio telescopes UTR-2, GURT and URAN-2. Specific features of the low-frequency solar radio emissions from a variety of sources are presented, with characterization of the optimized techniques that were applied in each case for evaluating physical parameters of the corona in the areas of decameter-wavelength radio wave generation. Results. The analysis of temporal, frequency and spatial characteristics of solar radio emissions has allowed suggesting a number of models for the coronal electron density distribution, and evaluating magnetic field strengths in the corona. Also, our experimental results have proven to be consistent with the observational data obtained in different frequency ranges and with the use of both ground based and space-borne instruments. Conclusions. The radio observations performed with Ukrainian radio telescopes have permitted studying, with high temporal, fre- quency and spatial resolutions, solar radio frequency emissions from various localized sources. Along with the large effective area and high sensitivity of the antennas, this permits application of a wide range of methods and tools aimed at detecting and analyzing solar bursts, of both strong and weak intensity, against the background of terrestrial interference of natural or artificial origin","PeriodicalId":33380,"journal":{"name":"Radio Physics and Radio Astronomy","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67142166","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Subject and Purpose. The thermal energy of the Tonga volcano reached 3.9 . 1018 J, its power amounted to 9.1 . 1013 W. The energy and power of the blast waves approached (6.7...7.5) . 1013 J and 1011 W, respectively. Ionospheric effects caused by the explosive eruption of the Tonga volcano on January 15, 2022 have received due attention. It was established that the ionospheric disturbances spread over global distances, with the greatest disturbances occurring in the near zone. The aim of the present paper is to describe aperiodic and quasi-periodic disturbances started by the Tonga volcano explosion and occurring in the near ionospheric zone. Methods and Methodology. To detect ionospheric disturbances generated by the volcanic eruption, temporal variations of the total electron content (TEC) in a vertical column in the ionosphere were analyzed. The total error of the TEC estimation did not exceed 0.1 TECU. Results. The quantitative characteristics of ionospheric disturbances caused by the explosive eruption of the Tonga volcano have been obtained. It was proved that the appearance of the ionospheric "hole" was caused directly by the volcanic explosion. With dis- tance away from the volcano, the TEC deficit in absolute values decreased from ~10 to ~2.5 TECU. As that was happening, the time taken to form the ionospheric "hole" increased from ~20 to ~100 min. Three groups of disturbances were observed. One group picks out disturbances having an N-shaped profile and caused by a blast wave with a speed exceeding ~1 000 m/s. Another group includes disturbances with a propagation speed within ~340...620 m/s, which is characteristic of atmospheric gravity waves at ionospheric heights. The last group is specified by the disturbance propagation speed within ~110 to 320 m/s. The disturbances of the kind can be generated by tsunamis, Lamb waves and atmospheric gravity waves. The wave disturbance periods varied within ~ 5 to 20 min, the disturbance amplitudes were within 0.5...1.0 TECU. Conclusions. It has been proven that aperiodic and quasi-periodic ionospheric disturbances in the near zone were caused directly by the explosion of the Tonga volcano.
{"title":"NEAR-ZONE IONOSPHERIC DISTURBANCES CAUSED BY EXPLOSIVE ERUPTION OF TONGA VOLCANO ON 15 JANUARY 2022","authors":"L. Chernogor, Yu. Mylovanov","doi":"10.15407/rpra28.03.212","DOIUrl":"https://doi.org/10.15407/rpra28.03.212","url":null,"abstract":"Subject and Purpose. The thermal energy of the Tonga volcano reached 3.9 . 1018 J, its power amounted to 9.1 . 1013 W. The energy and power of the blast waves approached (6.7...7.5) . 1013 J and 1011 W, respectively. Ionospheric effects caused by the explosive eruption of the Tonga volcano on January 15, 2022 have received due attention. It was established that the ionospheric disturbances spread over global distances, with the greatest disturbances occurring in the near zone. The aim of the present paper is to describe aperiodic and quasi-periodic disturbances started by the Tonga volcano explosion and occurring in the near ionospheric zone. Methods and Methodology. To detect ionospheric disturbances generated by the volcanic eruption, temporal variations of the total electron content (TEC) in a vertical column in the ionosphere were analyzed. The total error of the TEC estimation did not exceed 0.1 TECU. Results. The quantitative characteristics of ionospheric disturbances caused by the explosive eruption of the Tonga volcano have been obtained. It was proved that the appearance of the ionospheric \"hole\" was caused directly by the volcanic explosion. With dis- tance away from the volcano, the TEC deficit in absolute values decreased from ~10 to ~2.5 TECU. As that was happening, the time taken to form the ionospheric \"hole\" increased from ~20 to ~100 min. Three groups of disturbances were observed. One group picks out disturbances having an N-shaped profile and caused by a blast wave with a speed exceeding ~1 000 m/s. Another group includes disturbances with a propagation speed within ~340...620 m/s, which is characteristic of atmospheric gravity waves at ionospheric heights. The last group is specified by the disturbance propagation speed within ~110 to 320 m/s. The disturbances of the kind can be generated by tsunamis, Lamb waves and atmospheric gravity waves. The wave disturbance periods varied within ~ 5 to 20 min, the disturbance amplitudes were within 0.5...1.0 TECU. Conclusions. It has been proven that aperiodic and quasi-periodic ionospheric disturbances in the near zone were caused directly by the explosion of the Tonga volcano.","PeriodicalId":33380,"journal":{"name":"Radio Physics and Radio Astronomy","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135496230","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Subject and Purpose. Since decameter carbon radio recombination lines (RRLs) were detected for the first time more than forty years ago, they have significantly extended our knowledge of the physics, kinematics and chemistry of the cold rarefied interstellar medium (ISM). A large number of these lines have been observed towards various Galactic radio sources. The present paper describes our studies of decameter carbon RRLs in such Galactic directions as the sight-lines to the S140 emission nebula and to the large volume of cold neutral hydrogen known as the GSH 139-03-69 super shell. Methods and Methodology. Observations within a 1-MHz frequency band centered at 26 MHz were performed using the UTR-2 radio telescope and a multi-channel digital correlator. The UTR-2 is still the world largest and the most sensitive low-frequency radio telescope. Results.We report the detection of decameter carbon RRL series C627α – C637α from the medium lying towards the S140 nebula. The extents of RRL forming regions have been estimated. It is suggested that RRLs in the S140 direction are formed in the local ISM lying along the line of sight. The RRL-forming region is probably associated with omnipresent diffuse neutral HI gas in the Galactic plane rather than with S140 nebula itself. Toward the GSH 139-03-69 super shell, decameter RRLs have been detected as well. Likewise, they apparently originate from the local medium lying along the sight-line. Yet, the spectrum contains a RRL component corresponding to the absorption of the cold gas of the GSH 139-03-69 itself in the ISM. Conclusions. The obtained results indicate great possibilities of decameter carbon RRLs not only for cold ISM probing but also for making a good auxiliary tool for studying large complexes of extremely cold hydrogen HI in the Galaxy.
{"title":"Observations of decameter carbon radio recombination lines in several galactic directions. Part 1. Experimental study","authors":"Y. Vasylkivskyi, O. Konovalenko, S. Stepkin","doi":"10.15407/rpra28.03.201","DOIUrl":"https://doi.org/10.15407/rpra28.03.201","url":null,"abstract":"Subject and Purpose. Since decameter carbon radio recombination lines (RRLs) were detected for the first time more than forty years ago, they have significantly extended our knowledge of the physics, kinematics and chemistry of the cold rarefied interstellar medium (ISM). A large number of these lines have been observed towards various Galactic radio sources. The present paper describes our studies of decameter carbon RRLs in such Galactic directions as the sight-lines to the S140 emission nebula and to the large volume of cold neutral hydrogen known as the GSH 139-03-69 super shell. Methods and Methodology. Observations within a 1-MHz frequency band centered at 26 MHz were performed using the UTR-2 radio telescope and a multi-channel digital correlator. The UTR-2 is still the world largest and the most sensitive low-frequency radio telescope. Results.We report the detection of decameter carbon RRL series C627α – C637α from the medium lying towards the S140 nebula. The extents of RRL forming regions have been estimated. It is suggested that RRLs in the S140 direction are formed in the local ISM lying along the line of sight. The RRL-forming region is probably associated with omnipresent diffuse neutral HI gas in the Galactic plane rather than with S140 nebula itself. Toward the GSH 139-03-69 super shell, decameter RRLs have been detected as well. Likewise, they apparently originate from the local medium lying along the sight-line. Yet, the spectrum contains a RRL component corresponding to the absorption of the cold gas of the GSH 139-03-69 itself in the ISM. Conclusions. The obtained results indicate great possibilities of decameter carbon RRLs not only for cold ISM probing but also for making a good auxiliary tool for studying large complexes of extremely cold hydrogen HI in the Galaxy.","PeriodicalId":33380,"journal":{"name":"Radio Physics and Radio Astronomy","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135496232","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Subject and Purpose. Results are presented of numerical simulation of a patch antenna in the form of a planar unclosed annular radiator placed above an earthed plane. The work has been aimed at optimizing the key parameters of the antenna, like the degree of its matching with external circuits, achievable through proper selection of the excitation method and variation of the substrate permittivity, antenna gain, and power and polarization characteristics. Methods and Methodology. The antenna has been designed as an unclosed annular strip line. The angular width of the gap in the ring was varied during the optimization process. The antenna is excited via a segment of a coplanar line. The numerical simulation was performed for the unclosed resonator model, with all the limitations imposed on the model in the framework of the finite element method. The performance characteristics of the antenna have been optimized with account of the return loss level, gain magnitude and ellipticity over the given frequency range. Results. Frequency and power characteristics of the patch antenna based on an unclosed annular strip-line radiator have been ana- lyzed and optimized over a broad frequency range. The impact of key parameters of the structure upon its performance characteristics has been established, specifically of the angular width of the gap in the unclosed ring, separation from the ground plane, and dielectric permittivity value in the substrate. The possibility has been demonstrated of generating radiation fields of an elliptical polarization which is rather close to circular. Conclusions. The frequency, spectral and power characteristics studied of a patch antenna built around a planar unclosed annu- lar strip-line radiator above an earthed plane. The numerical modeling was performed within the framework of the finite element method. The principal dependences of the antenna’s electrodynamic performance upon such parameters as geometry, characteristic dimensions and material constants have been condsidered. The results obtained allow suggesting application of such antennas in the capacity of both independent radiators and elements of phased antenna arrays.
{"title":"A BROADBAND PATCH ANTENNA BASED ON A PLANAR UNCLOSED ANNULAR RADIATOR","authors":"S. Pogarsky, D. Mayboroda","doi":"10.15407/rpra28.02.158","DOIUrl":"https://doi.org/10.15407/rpra28.02.158","url":null,"abstract":"Subject and Purpose. Results are presented of numerical simulation of a patch antenna in the form of a planar unclosed annular radiator placed above an earthed plane. The work has been aimed at optimizing the key parameters of the antenna, like the degree of its matching with external circuits, achievable through proper selection of the excitation method and variation of the substrate permittivity, antenna gain, and power and polarization characteristics. Methods and Methodology. The antenna has been designed as an unclosed annular strip line. The angular width of the gap in the ring was varied during the optimization process. The antenna is excited via a segment of a coplanar line. The numerical simulation was performed for the unclosed resonator model, with all the limitations imposed on the model in the framework of the finite element method. The performance characteristics of the antenna have been optimized with account of the return loss level, gain magnitude and ellipticity over the given frequency range. Results. Frequency and power characteristics of the patch antenna based on an unclosed annular strip-line radiator have been ana- lyzed and optimized over a broad frequency range. The impact of key parameters of the structure upon its performance characteristics has been established, specifically of the angular width of the gap in the unclosed ring, separation from the ground plane, and dielectric permittivity value in the substrate. The possibility has been demonstrated of generating radiation fields of an elliptical polarization which is rather close to circular. Conclusions. The frequency, spectral and power characteristics studied of a patch antenna built around a planar unclosed annu- lar strip-line radiator above an earthed plane. The numerical modeling was performed within the framework of the finite element method. The principal dependences of the antenna’s electrodynamic performance upon such parameters as geometry, characteristic dimensions and material constants have been condsidered. The results obtained allow suggesting application of such antennas in the capacity of both independent radiators and elements of phased antenna arrays.","PeriodicalId":33380,"journal":{"name":"Radio Physics and Radio Astronomy","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67142267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Subject and Purpose. The subject of this paper is to review the principal methods of fractal and multifractal analysis of signals and processes, in combination with a detailed consideration of the algorithms that can provide for a successful practical implementation of the methods described. Methods and Methodology. The results presented concern modeling of both deterministic and stochastic fractal and multifractal signals and processes. The corresponding practical methods of analysis are considered, with discussion of their essential features, advantages and disadvantages, as well as of the problems of application that may exist. Results. Several approaches have been discussed as to categorizing the signals and processes within the notion of fractality. A few tens of models of deterministic and stochastic fractal or multifractal signals and processes have been analyzed in detail. Over twenty methods of monofractal analysis have been analyzed, with identifi cation of their features, advantages or disadvantages, and limits of applicability. The expediency of resorting to complex methods of monofractal analysis has also been discussed. Those methods are not based upon application of fractal analysis techniques alone but rather combine them with linear and nonlinear integral time-frequency transforms. The effectiveness of the ten most popular multifractal analysis techniques has been confirmed, with consideration of their special features, advantages and drawbacks. Conclusion. The mathematical foundations have been presented which underlie modern methods of analysis and modeling of fractal and multifractal signals and processes. The methods discussed may allow revealing a great amount of unique hidden information on the world around us.
{"title":"FRACTAL RADIOPHYSICS. Part 2. FRACTAL AND MULTIFRACTAL ANALYSIS METHODS OF SIGNALS AND PROCESSES","authors":"O. Lazorenko, L. Chernogor","doi":"10.15407/rpra28.01.005","DOIUrl":"https://doi.org/10.15407/rpra28.01.005","url":null,"abstract":"Subject and Purpose. The subject of this paper is to review the principal methods of fractal and multifractal analysis of signals and processes, in combination with a detailed consideration of the algorithms that can provide for a successful practical implementation of the methods described. Methods and Methodology. The results presented concern modeling of both deterministic and stochastic fractal and multifractal signals and processes. The corresponding practical methods of analysis are considered, with discussion of their essential features, advantages and disadvantages, as well as of the problems of application that may exist. Results. Several approaches have been discussed as to categorizing the signals and processes within the notion of fractality. A few tens of models of deterministic and stochastic fractal or multifractal signals and processes have been analyzed in detail. Over twenty methods of monofractal analysis have been analyzed, with identifi cation of their features, advantages or disadvantages, and limits of applicability. The expediency of resorting to complex methods of monofractal analysis has also been discussed. Those methods are not based upon application of fractal analysis techniques alone but rather combine them with linear and nonlinear integral time-frequency transforms. The effectiveness of the ten most popular multifractal analysis techniques has been confirmed, with consideration of their special features, advantages and drawbacks. Conclusion. The mathematical foundations have been presented which underlie modern methods of analysis and modeling of fractal and multifractal signals and processes. The methods discussed may allow revealing a great amount of unique hidden information on the world around us.","PeriodicalId":33380,"journal":{"name":"Radio Physics and Radio Astronomy","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67142053","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Stanislavsky, A. Koval, I. Bubnov, A. Brazhenko
Subject and Purpose. This part of the paper continues presentation of results of the solar radio emission studies performed with Ukrainian radio telescopes over the past 20 years. The importance is stressed of developing adequate instruments and methods for identifying the nature of decameter-wavelength radio emissions from the Sun. Methods and Methodology. The low frequency Ukrainian radio telescopes UTR-2, GURT and URAN-2 have been used in the project along with other ground- and space based instruments in order to achieve a comprehensive understanding of physical conditions in the solar corona. Results. Special methods and tools have been developed for studying radio frequency burst emissions against the background of strong interference. Unique data have been obtained concerning sources of sporadic radio emissions from the Sun, as well as the contribution from wave propagation effects and the impact of the ionosphere on the results of observations. The most significant observational and theoretical results are presented, obtained in the study of solar low frequency emissions over the past 20 years. Solar radio emissions are shown to be efficient sounding signals not for the solar corona alone but for the Earth’s ionosphere as well, which allows identifying its impact on the results of radio astronomy observations. Conclusions. The Ukrainian radio telescopes of the meter and decameter wavebands currently are unrivalled tools for investigating the Universe in the low-frequency range of radio waves. Owing to their advanced characteristics, they make a significant contribution to the progress of world’s solar radio astronomy.
{"title":"Stanislavsky, A.A., Koval, A.A., Bubnov, I.N., and Brazhenko, A.I. Progress in the study of decameter-wave- length solar radio emission with Ukrainian radio telescopes. Part 2. (Invited paper)","authors":"A. Stanislavsky, A. Koval, I. Bubnov, A. Brazhenko","doi":"10.15407/rpra28.03.183","DOIUrl":"https://doi.org/10.15407/rpra28.03.183","url":null,"abstract":"Subject and Purpose. This part of the paper continues presentation of results of the solar radio emission studies performed with Ukrainian radio telescopes over the past 20 years. The importance is stressed of developing adequate instruments and methods for identifying the nature of decameter-wavelength radio emissions from the Sun. Methods and Methodology. The low frequency Ukrainian radio telescopes UTR-2, GURT and URAN-2 have been used in the project along with other ground- and space based instruments in order to achieve a comprehensive understanding of physical conditions in the solar corona. Results. Special methods and tools have been developed for studying radio frequency burst emissions against the background of strong interference. Unique data have been obtained concerning sources of sporadic radio emissions from the Sun, as well as the contribution from wave propagation effects and the impact of the ionosphere on the results of observations. The most significant observational and theoretical results are presented, obtained in the study of solar low frequency emissions over the past 20 years. Solar radio emissions are shown to be efficient sounding signals not for the solar corona alone but for the Earth’s ionosphere as well, which allows identifying its impact on the results of radio astronomy observations. Conclusions. The Ukrainian radio telescopes of the meter and decameter wavebands currently are unrivalled tools for investigating the Universe in the low-frequency range of radio waves. Owing to their advanced characteristics, they make a significant contribution to the progress of world’s solar radio astronomy.","PeriodicalId":33380,"journal":{"name":"Radio Physics and Radio Astronomy","volume":"193 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135495937","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P. Melezhik, A. Kirilenko, O. Kostenko, S. Masalov
The paper is dedicated to the memory of V.P. Shestopalov, an outstanding scientist known for his great contributions to radio physics, electronics, theoretical and mathematical physics. While being a holder of many formal academic degrees and titles, like PhD, DSc (Phys.-Math.), Professor, and Fellow Member of the Academy of Sciences, he was particularly honored as the founder of a scientific school vigorously developing diff raction theory and diffractional electronics. Th at school has been associated with the O.Ya. Usikov Institute for Radio Physics and Electronics where Dr. Shestopalov was Director till 1993. Today, we are marking the 100-th anniversary of Victor P. Shestopalov.
{"title":"V. P. SHESTOPALOV AND HIS SCIENTIFIC SCHOOL: FROM QUASISTATICS TO QUASIOPTICS (to mark V.P.'s birth centenary)","authors":"P. Melezhik, A. Kirilenko, O. Kostenko, S. Masalov","doi":"10.15407/rpra28.01.080","DOIUrl":"https://doi.org/10.15407/rpra28.01.080","url":null,"abstract":"The paper is dedicated to the memory of V.P. Shestopalov, an outstanding scientist known for his great contributions to radio physics, electronics, theoretical and mathematical physics. While being a holder of many formal academic degrees and titles, like PhD, DSc (Phys.-Math.), Professor, and Fellow Member of the Academy of Sciences, he was particularly honored as the founder of a scientific school vigorously developing diff raction theory and diffractional electronics. Th at school has been associated with the O.Ya. Usikov Institute for Radio Physics and Electronics where Dr. Shestopalov was Director till 1993. Today, we are marking the 100-th anniversary of Victor P. Shestopalov.","PeriodicalId":33380,"journal":{"name":"Radio Physics and Radio Astronomy","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67142156","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Purpose. Diff raction problem of the H11 and E11 waves of circular waveguide by the fi nite and semi-infi nite system of similar discontinuities is considered. Four types of discontinuities are considered: iris, disk, ring, annular slot. Th e distance between irregularities is the same. Th e waveguide is fi lled by the dielectric with losses. Design/methodology/approach. To solve the problem we chose the operator method. While so-called key problem, the diff raction problem by a single discontinuity, is solved by the method of moments. The field in the domain of the obstacle is represented as a series in terms of eigenwaves of infi nite waveguide which cross section coincides with the cross section of discontinuity, with unknown amplitudes. To fi nd the amplitudes we obtain the infi nite system of equations, which is solved by the reduction. As a result, the transmission and refl ection operators of a key-problem are obtained. The properties of fi nite sequence are determined from the operator equations relatively amplitudes of the scattered field. To write these equations the iterative procedure is used. The properties of the structure, which consists of N discontinuities are obtained under assumption that the properties of the structure, which consists of N – 1 discontinuity are known. The reflection operator of the semi-infi nite system is obtained from known non-linear operator equation of the second kind. Findings. The systems of equations for every single discontinuity are obtained. The operator equations relatively amplitudes of the scattered fields for fi nite system are presented. With the help of the created model the dependences of the transmission, refl ection coeffi cients of the H11 wave as well as transformation coeffi cients of the H11 to E11 wave of the circular waveguide on the wavenumber, geometrical and material parameters for fi nite and semi-infi nite structures are studied. The comparison of the results obtained by presented method with the results obtained in HFSS is made. Conclusions. With the use of the operator method the scattering model of the H1n and E1n eigenwaves by the system of annular discontinuities of zero thickness in a circular waveguide is built. Th e study of the scattering characteristics on the parameters is made. The coincidence of the behavior of the curves obtained by the presented method with those obtained in HFSS allows us to draw a conclusion about the correctness of the results. Th e results can be used during creation of a series of the microwaves and optic devices.
{"title":"OPERATOR METHOD IN DIFFRACTION PROBLEM OF WAVES OF CIRCULAR WAVEGUIDE BY THE ANNULAR DISCONTINUITIES","authors":"M. Kaliberda, L. Lytvynenko, S. Pogarsky","doi":"10.15407/rpra27.01.005","DOIUrl":"https://doi.org/10.15407/rpra27.01.005","url":null,"abstract":"Purpose. Diff raction problem of the H11 and E11 waves of circular waveguide by the fi nite and semi-infi nite system of similar discontinuities is considered. Four types of discontinuities are considered: iris, disk, ring, annular slot. Th e distance between irregularities is the same. Th e waveguide is fi lled by the dielectric with losses. Design/methodology/approach. To solve the problem we chose the operator method. While so-called key problem, the diff raction problem by a single discontinuity, is solved by the method of moments. The field in the domain of the obstacle is represented as a series in terms of eigenwaves of infi nite waveguide which cross section coincides with the cross section of discontinuity, with unknown amplitudes. To fi nd the amplitudes we obtain the infi nite system of equations, which is solved by the reduction. As a result, the transmission and refl ection operators of a key-problem are obtained. The properties of fi nite sequence are determined from the operator equations relatively amplitudes of the scattered field. To write these equations the iterative procedure is used. The properties of the structure, which consists of N discontinuities are obtained under assumption that the properties of the structure, which consists of N – 1 discontinuity are known. The reflection operator of the semi-infi nite system is obtained from known non-linear operator equation of the second kind. Findings. The systems of equations for every single discontinuity are obtained. The operator equations relatively amplitudes of the scattered fields for fi nite system are presented. With the help of the created model the dependences of the transmission, refl ection coeffi cients of the H11 wave as well as transformation coeffi cients of the H11 to E11 wave of the circular waveguide on the wavenumber, geometrical and material parameters for fi nite and semi-infi nite structures are studied. The comparison of the results obtained by presented method with the results obtained in HFSS is made. Conclusions. With the use of the operator method the scattering model of the H1n and E1n eigenwaves by the system of annular discontinuities of zero thickness in a circular waveguide is built. Th e study of the scattering characteristics on the parameters is made. The coincidence of the behavior of the curves obtained by the presented method with those obtained in HFSS allows us to draw a conclusion about the correctness of the results. Th e results can be used during creation of a series of the microwaves and optic devices.","PeriodicalId":33380,"journal":{"name":"Radio Physics and Radio Astronomy","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45127183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Subject and Purpose. The paper is concerned with the behavior of a nonlinear dynamic system that has two degrees of freedom and whose joint nonlinearity is established by all the nonlinear coupling between the degrees of freedom. The purpose is to find out if the Krylov—Bogolyubov—Mitropolsky (KBM) method is applicable to a system of partial differential equations. Methods and Methodology. The consideration of the problem is by the Krylov—Bogolyubov—Mitropolsky method in the first approximation. Then the results are treated using numerical methods. Results. An electromechanical system with two degrees of freedom and a known parametric resonance has been studied using the Krylov—Bogolyubov—Mitropolsky method in the first approximation. The phase space of the system has been described. It has been shown that the obtained solution covers an energy periodic transfer between the two degrees of freedom. The difference between the considered oscillation system and its analogs discussed in the literature lies in that the considered circuit is parametrically excited by an internal force rather than external one. In a similar system of two circuits connected through a diode, the coupling includes a linear component. In the system of present concern, the coupling is all-nonlinear. Conclusion. The obtained results are of interest for the research into internal nonlinear resonances between degrees of freedom in an oscillation system that has two degrees of freedom and whose joint nonlinearity is due to all the nonlinear coupling between the degrees of freedom. The considered system can serve a test example in the development of programs implementing the Krylov—Bo- golyubov—Mitropolsky method as applied to an oscillation system with numerous degrees of freedom and a small nonlinearity.
{"title":"AN INTERNAL NONLINEAR RESONANCE IN AN OSCILLATION SYSTEM WITH TWO DEGREES OF FREEDOM","authors":"Y. Kornienko, L. V. Stulova, D. Masalov","doi":"10.15407/rpra27.01.017","DOIUrl":"https://doi.org/10.15407/rpra27.01.017","url":null,"abstract":"Subject and Purpose. The paper is concerned with the behavior of a nonlinear dynamic system that has two degrees of freedom and whose joint nonlinearity is established by all the nonlinear coupling between the degrees of freedom. The purpose is to find out if the Krylov—Bogolyubov—Mitropolsky (KBM) method is applicable to a system of partial differential equations. Methods and Methodology. The consideration of the problem is by the Krylov—Bogolyubov—Mitropolsky method in the first approximation. Then the results are treated using numerical methods. Results. An electromechanical system with two degrees of freedom and a known parametric resonance has been studied using the Krylov—Bogolyubov—Mitropolsky method in the first approximation. The phase space of the system has been described. It has been shown that the obtained solution covers an energy periodic transfer between the two degrees of freedom. The difference between the considered oscillation system and its analogs discussed in the literature lies in that the considered circuit is parametrically excited by an internal force rather than external one. In a similar system of two circuits connected through a diode, the coupling includes a linear component. In the system of present concern, the coupling is all-nonlinear. Conclusion. The obtained results are of interest for the research into internal nonlinear resonances between degrees of freedom in an oscillation system that has two degrees of freedom and whose joint nonlinearity is due to all the nonlinear coupling between the degrees of freedom. The considered system can serve a test example in the development of programs implementing the Krylov—Bo- golyubov—Mitropolsky method as applied to an oscillation system with numerous degrees of freedom and a small nonlinearity.","PeriodicalId":33380,"journal":{"name":"Radio Physics and Radio Astronomy","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46994838","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
I. Kuzmichev, B. I. Muzychishin, А. Y. Popkov, Аlexander V. May, A. May
Purpose. The excitation efficiency is investigated of the first higher-order axially asymmetric oscillation mode (TEM10q) excited in a hemispherical open resonator (OR) at the frequencies of the fundamental and second-order harmonics of the Gunn diode in the 4-mm and 2-mm wavelength ranges. The hemispherical resonator is coupled to its input waveguide via aperture-type coupling elements. The diameter 2a of the OR mirror apertures is 38 mm, while the curvature radius of the spherical reflector is R = 39 mm and the normalized distance between the mirrors is L/R = 0.593. Two aperture coupling elements of dimensions a× b = 6.9 × 9.6 mm are used to excite the OR. They permit controlling separately the functions of field-to-field matching (modes in the resonator and in the waveguide) and volume- to-volume coupling of the structural elements (the resonator and the waveguide). They are located at the center of the planar mirror. The field matching is determined by the geometric dimensions of the coupling elements, whereas the coupling matching is determined by the period of the one-dimensional E-polarized grating in their apertures. The Gunn diodes are used as generators, operating at the frequencies of the fundamental (75 GHz) andthe second-order (150 GHz) harmonics. The excitation efficiency of the TEM1011 oscillation in the OR of the geometry specified here, using aperture-type coupling elements as described, is 81.5%. Design/methodology/approach. The excitation efficiency of higher-order oscillation modes ТЕМ10q in the OR being driven by an incident ТЕ10 mode that arrives via two rectangular guides, is evalua-ted using the antenna surface utilization factor. The reflection coefficient from the OR and the loaded Q-factor are estimated in the familiar technique of partial reflection coefficients summation. Findings. As has been shown, in an OR of parameters 2а= 38 mm, R= 78 mm, and L/R= 0.287 TEM1022 oscillations are excited at the frequency of the Gunn diode’s second-order harmonic (i.e., 150 GHz) with an efficiency of 84%. In that same resonator, the excitation efficiency of the TEM1011 mode at the fundamental Gunn diode’s harmonic (frequency of 75 GHz) equals 54%. By placing one-dimensional (E-polarized) wire gratings in the aperture of the coupling elements it proves possible to match the resonator with the waveguide. It has been found that in the case of a l = 0.2 mm spatial period of the wire grating and matched excitation of the resonator at f = 150 GHz (i.e. Г150 = 0), the reflection coefficient Г75 from the OR at f = 75 GHz equals 0.637. Upon excitation in the OR of oscillations in the TEM1022 mode, the total loss at f = 150 GHz is –1.23 dB. With TEM1011 oscillations excited in the same resonator at a frequency of 75 GHz, the total losses increase up to –5.4 dB. Conclusions. The analysis has shown that an OR implementing the proposed method of excitation of higher-order axially asymmetric for constructing a subterahertz range local oscillator.
{"title":"THE RESONANT SYSTEM OF A SUB-TERAHERTZ LOCAL OSCILLATOR","authors":"I. Kuzmichev, B. I. Muzychishin, А. Y. Popkov, Аlexander V. May, A. May","doi":"10.15407/rpra27.01.064","DOIUrl":"https://doi.org/10.15407/rpra27.01.064","url":null,"abstract":"Purpose. The excitation efficiency is investigated of the first higher-order axially asymmetric oscillation mode (TEM10q) excited in a hemispherical open resonator (OR) at the frequencies of the fundamental and second-order harmonics of the Gunn diode in the 4-mm and 2-mm wavelength ranges. The hemispherical resonator is coupled to its input waveguide via aperture-type coupling elements. The diameter 2a of the OR mirror apertures is 38 mm, while the curvature radius of the spherical reflector is R = 39 mm and the normalized distance between the mirrors is L/R = 0.593. Two aperture coupling elements of dimensions a× b = 6.9 × 9.6 mm are used to excite the OR. They permit controlling separately the functions of field-to-field matching (modes in the resonator and in the waveguide) and volume- to-volume coupling of the structural elements (the resonator and the waveguide). They are located at the center of the planar mirror. The field matching is determined by the geometric dimensions of the coupling elements, whereas the coupling matching is determined by the period of the one-dimensional E-polarized grating in their apertures. The Gunn diodes are used as generators, operating at the frequencies of the fundamental (75 GHz) andthe second-order (150 GHz) harmonics. The excitation efficiency of the TEM1011 oscillation in the OR of the geometry specified here, using aperture-type coupling elements as described, is 81.5%. Design/methodology/approach. The excitation efficiency of higher-order oscillation modes ТЕМ10q in the OR being driven by an incident ТЕ10 mode that arrives via two rectangular guides, is evalua-ted using the antenna surface utilization factor. The reflection coefficient from the OR and the loaded Q-factor are estimated in the familiar technique of partial reflection coefficients summation. Findings. As has been shown, in an OR of parameters 2а= 38 mm, R= 78 mm, and L/R= 0.287 TEM1022 oscillations are excited at the frequency of the Gunn diode’s second-order harmonic (i.e., 150 GHz) with an efficiency of 84%. In that same resonator, the excitation efficiency of the TEM1011 mode at the fundamental Gunn diode’s harmonic (frequency of 75 GHz) equals 54%. By placing one-dimensional (E-polarized) wire gratings in the aperture of the coupling elements it proves possible to match the resonator with the waveguide. It has been found that in the case of a l = 0.2 mm spatial period of the wire grating and matched excitation of the resonator at f = 150 GHz (i.e. Г150 = 0), the reflection coefficient Г75 from the OR at f = 75 GHz equals 0.637. Upon excitation in the OR of oscillations in the TEM1022 mode, the total loss at f = 150 GHz is –1.23 dB. With TEM1011 oscillations excited in the same resonator at a frequency of 75 GHz, the total losses increase up to –5.4 dB. Conclusions. The analysis has shown that an OR implementing the proposed method of excitation of higher-order axially asymmetric for constructing a subterahertz range local oscillator.","PeriodicalId":33380,"journal":{"name":"Radio Physics and Radio Astronomy","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44480189","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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