PULSED POWER TO MICROWAVES CONVERSION IN NONLINEAR TRANSMISSION LINES
Purpose: Experimental results and numerical simulations are presented, concerning effects of microwave generation in coaxial transmission lines which are fed with unipolar, high voltage electric pulses. The work is aimed at clarifying the relative importance of several mechanisms that could be respo...
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Видавничий дім «Академперіодика»
2021
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Radio physics and radio astronomy| id |
oai:ri.kharkov.ua:article-1362 |
|---|---|
| record_format |
ojs |
| institution |
Radio physics and radio astronomy |
| collection |
OJS |
| language |
English |
| topic |
unipolar pulse coaxial transmission line microwave frequency oscillations dispersion laws waveguide modes однополярний імпульс коаксіальна лінія передачі мікрохвилеві коливання закони дисперсії хвилеводні моди unipolar pulse coaxial transmission line microwave frequency oscillations dispersion laws waveguide modes |
| spellingShingle |
unipolar pulse coaxial transmission line microwave frequency oscillations dispersion laws waveguide modes однополярний імпульс коаксіальна лінія передачі мікрохвилеві коливання закони дисперсії хвилеводні моди unipolar pulse coaxial transmission line microwave frequency oscillations dispersion laws waveguide modes Karelin, S. Y. Korenev, V. G. Krasovitsky, V. B. Lebedenko, A. N. Magda, I. I. Mukhin, V. S. Sinitsin, V. G. Volovenko, N. V. PULSED POWER TO MICROWAVES CONVERSION IN NONLINEAR TRANSMISSION LINES |
| topic_facet |
unipolar pulse coaxial transmission line microwave frequency oscillations dispersion laws waveguide modes однополярний імпульс коаксіальна лінія передачі мікрохвилеві коливання закони дисперсії хвилеводні моди unipolar pulse coaxial transmission line microwave frequency oscillations dispersion laws waveguide modes |
| format |
Article |
| author |
Karelin, S. Y. Korenev, V. G. Krasovitsky, V. B. Lebedenko, A. N. Magda, I. I. Mukhin, V. S. Sinitsin, V. G. Volovenko, N. V. |
| author_facet |
Karelin, S. Y. Korenev, V. G. Krasovitsky, V. B. Lebedenko, A. N. Magda, I. I. Mukhin, V. S. Sinitsin, V. G. Volovenko, N. V. |
| author_sort |
Karelin, S. Y. |
| title |
PULSED POWER TO MICROWAVES CONVERSION IN NONLINEAR TRANSMISSION LINES |
| title_short |
PULSED POWER TO MICROWAVES CONVERSION IN NONLINEAR TRANSMISSION LINES |
| title_full |
PULSED POWER TO MICROWAVES CONVERSION IN NONLINEAR TRANSMISSION LINES |
| title_fullStr |
PULSED POWER TO MICROWAVES CONVERSION IN NONLINEAR TRANSMISSION LINES |
| title_full_unstemmed |
PULSED POWER TO MICROWAVES CONVERSION IN NONLINEAR TRANSMISSION LINES |
| title_sort |
pulsed power to microwaves conversion in nonlinear transmission lines |
| title_alt |
PULSED POWER TO MICROWAVES CONVERSION IN NONLINEAR TRANSMISSION LINES ПЕРЕТВОРЕННЯ ІМПУЛЬСНОЇ ЕНЕРГІЇ В МІКРОХВИЛІ В НЕЛІНІЙНИХ ЛІНІЯХ ПЕРЕДАЧІ |
| description |
Purpose: Experimental results and numerical simulations are presented, concerning effects of microwave generation in coaxial transmission lines which are fed with unipolar, high voltage electric pulses. The work is aimed at clarifying the relative importance of several mechanisms that could be responsible for the appearance of microwave-frequency oscillations in the course of pulse propagation through the guiding structure.Design/methodology/approach: Dispersive and filtering properties of coaxial waveguides that involve three structural sections are discussed. These latter follow one another along the axis of symmetry. Two identical sections at the input and output are filled with an isotropic liquid dielectric, while the middle part may, in addition, be either partially or fully filled with a non-conductive gyrotropic material. The inserted core represents a set of ferrite rings showing a nonlinear response to the initial high voltage, pulsed excitation. Throughout the series of measurements, the diameters of the inner conductor and of the ferrite core were kept constant. The outer conductor’s diameter was varied to permit analysis of the effect of that size proper and of the degree to which the cross-section is fi lled with ferrite. The gyrotropic properties of the ferrimagnetic material were realized through application of a magnetic bias field from an external coil. The measurements were made for a variety of pulsed voltage magnitudes from the range of hundreds of kilovolts, and magnetic bias fields of tens kiloamperes per meter.Findings: As observed in our experiments, as well as in papers by other writers, a unipolar pulse coming from the radially uniform front-end section, further on gives rise to quasi-monochromatic voltage oscillations. These appear as soon as the pulse has advanced a sufficient distance into the radially nonuniform portion of the guide. The oscillations may consist of a small number of quasi-periods, which suggests a large spectral line width. However, by properly selecting geometric parameters of the wave guiding line and the characteristics of the initial pulsed waveform it proves possible to obtain output frequencies of about units of gigahertz and pulse powers at subgigawatt levels.Conclusions: The frequencies and amplitudes of the appearing oscillations, as well as their spectral widths, are governed by the complex of dispersive and non-linear properties of the guiding structure. The diameters of the inner and outer coaxial conductors in the line, diameter of the ferrimagnetic insert and its intrinsic linear dispersion determine the set of waveguide modes capable of propagating through the line. An oscillating part of the waveform may appear and get separated from the main body of the pulse if it has originated at a higher frequency than the cut-off value for a different mode than the initial TEM.Key words: unipolar pulse, coaxial transmission line, microwave frequency oscillations, dispersion laws, waveguide modesManuscript submitted 10.08.2021Radio phys. radio astron. 2021, 26(3): 250-255REFERENCES1. DOLAN, J. E., 1999. Simulation of shock waves in ferriteloaded coaxial transmission lines with axial bias. J. Phys. Appl. Phys. vol. 32, no. 15, pp. 1826–1831. DOI: https://doi.org/10.1088/0022-3727/32/15/3102. GUBANOV, V. P., GUNIN, A. V., KOVALCHUK, O. B., KUTENKOV, V. O., ROMANCHENKO, I. V. and ROSTOV, V. V., 2009. Effective transformation of the energy of high-voltage pulses into high-frequency oscillations using a saturated-ferrite-loaded transmission line. Tech. Phys. Lett. vol. 35, is. 7, pp. 626–628. DOI: https://doi.org/10.1134/S10637850090701163. VASELAAR, A., 2011. Experimentation and modeling of pulse sharpening and gyromagnetic precession within a nonlinear transmission line [online]. PhD thesis ed. Texas Tech University [viewed 8 July 2021]. Available from: http://hdl. handle.net/2346/ETD-TTU-2011-08-16634. REALE, D. V., 2013. Coaxial Ferrimagnetic Based Gyromagnetic Nonlinear Transmission Lines as Compact High Power Microwave Sources [online]. PhD thesis ed. Texas Tech University [viewed 9 July 2021]. Available from: http:// hdl.handle.net/2346/581995. KATAYEV, I. G., 1966. Electromagnetic shock waves. London: Illife Books Ltd.6. FURUYA, S., MATSUMOTO, H., FUKUDA, H., OHBOSHI, T., TAKANO, S. and IRISAWA, J., 2002. Simulation of Nonlinear Coaxial Line Using Ferrite Beads. Jpn. J. Appl. Phys. vol. 41, no. 11R, pp. 6536–6540. DOI: https://doi.org/10.1143/JJAP.41.65367. ROSTOV, V. V., BYKOV, N. M, BYKOV, D. N., KLIMOV, A. I., KOVALCHUK, O. B. and ROMANCHENKO, I. V., 2010. Generation of Subgigawatt RF Pulses in Nonlinear Transmission Lines. IEEE Trans. Plasma Sci. vol. 38, no. 10, p. 2681–2685. DOI: https://doi.org/10.1109/TPS.2010.20487228. AHN, J.-W., KARELIN, S. Y., KWON, H.-O., MAGDA, I. I. and SINITSIN, V. G., 2015. Exciting Yigh Frequency Oscillations in a Coaxial Transmission Line with a Magnetized Ferrite. J. Magn. vol. 20, no. 4, pp. 460–465. DOI: https://doi.org/10.4283/JMAG.2015.20.4.4609. KARELIN, S. Y., 2017. FDTD Analysis of Nonlinear Magnetized Ferrites: Application to Modeling Oscillations Forming in Coaxial Lines With Ferrite. Radiofis. Electron. vol. 8(22), no. 1, pp. 51–56. (in Russian). DOI: https://doi.org/10.15407/rej2017.01.05110. VESELOV, G. I. and RAYEVSKY, S. B., 1988. Layered metal-dielectric waveguides. Moscow, Russia: Radio i Svyaz’ Publ. (in Russian). |
| publisher |
Видавничий дім «Академперіодика» |
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2021 |
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http://rpra-journal.org.ua/index.php/ra/article/view/1362 |
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oai:ri.kharkov.ua:article-13622021-09-22T11:16:52Z PULSED POWER TO MICROWAVES CONVERSION IN NONLINEAR TRANSMISSION LINES ПЕРЕТВОРЕННЯ ІМПУЛЬСНОЇ ЕНЕРГІЇ В МІКРОХВИЛІ В НЕЛІНІЙНИХ ЛІНІЯХ ПЕРЕДАЧІ PULSED POWER TO MICROWAVES CONVERSION IN NONLINEAR TRANSMISSION LINES Karelin, S. Y. Korenev, V. G. Krasovitsky, V. B. Lebedenko, A. N. Magda, I. I. Mukhin, V. S. Sinitsin, V. G. Volovenko, N. V. unipolar pulse; coaxial transmission line; microwave frequency oscillations; dispersion laws; waveguide modes однополярний імпульс; коаксіальна лінія передачі; мікрохвилеві коливання; закони дисперсії; хвилеводні моди unipolar pulse; coaxial transmission line; microwave frequency oscillations; dispersion laws; waveguide modes Purpose: Experimental results and numerical simulations are presented, concerning effects of microwave generation in coaxial transmission lines which are fed with unipolar, high voltage electric pulses. The work is aimed at clarifying the relative importance of several mechanisms that could be responsible for the appearance of microwave-frequency oscillations in the course of pulse propagation through the guiding structure.Design/methodology/approach: Dispersive and filtering properties of coaxial waveguides that involve three structural sections are discussed. These latter follow one another along the axis of symmetry. Two identical sections at the input and output are filled with an isotropic liquid dielectric, while the middle part may, in addition, be either partially or fully filled with a non-conductive gyrotropic material. The inserted core represents a set of ferrite rings showing a nonlinear response to the initial high voltage, pulsed excitation. Throughout the series of measurements, the diameters of the inner conductor and of the ferrite core were kept constant. The outer conductor’s diameter was varied to permit analysis of the effect of that size proper and of the degree to which the cross-section is fi lled with ferrite. The gyrotropic properties of the ferrimagnetic material were realized through application of a magnetic bias field from an external coil. The measurements were made for a variety of pulsed voltage magnitudes from the range of hundreds of kilovolts, and magnetic bias fields of tens kiloamperes per meter.Findings: As observed in our experiments, as well as in papers by other writers, a unipolar pulse coming from the radially uniform front-end section, further on gives rise to quasi-monochromatic voltage oscillations. These appear as soon as the pulse has advanced a sufficient distance into the radially nonuniform portion of the guide. The oscillations may consist of a small number of quasi-periods, which suggests a large spectral line width. However, by properly selecting geometric parameters of the wave guiding line and the characteristics of the initial pulsed waveform it proves possible to obtain output frequencies of about units of gigahertz and pulse powers at subgigawatt levels.Conclusions: The frequencies and amplitudes of the appearing oscillations, as well as their spectral widths, are governed by the complex of dispersive and non-linear properties of the guiding structure. The diameters of the inner and outer coaxial conductors in the line, diameter of the ferrimagnetic insert and its intrinsic linear dispersion determine the set of waveguide modes capable of propagating through the line. An oscillating part of the waveform may appear and get separated from the main body of the pulse if it has originated at a higher frequency than the cut-off value for a different mode than the initial TEM.Key words: unipolar pulse, coaxial transmission line, microwave frequency oscillations, dispersion laws, waveguide modesManuscript submitted 10.08.2021Radio phys. radio astron. 2021, 26(3): 250-255REFERENCES1. DOLAN, J. E., 1999. Simulation of shock waves in ferriteloaded coaxial transmission lines with axial bias. J. Phys. Appl. Phys. vol. 32, no. 15, pp. 1826–1831. DOI: https://doi.org/10.1088/0022-3727/32/15/3102. GUBANOV, V. P., GUNIN, A. V., KOVALCHUK, O. B., KUTENKOV, V. O., ROMANCHENKO, I. V. and ROSTOV, V. V., 2009. Effective transformation of the energy of high-voltage pulses into high-frequency oscillations using a saturated-ferrite-loaded transmission line. Tech. Phys. Lett. vol. 35, is. 7, pp. 626–628. DOI: https://doi.org/10.1134/S10637850090701163. VASELAAR, A., 2011. Experimentation and modeling of pulse sharpening and gyromagnetic precession within a nonlinear transmission line [online]. PhD thesis ed. Texas Tech University [viewed 8 July 2021]. Available from: http://hdl. handle.net/2346/ETD-TTU-2011-08-16634. REALE, D. V., 2013. Coaxial Ferrimagnetic Based Gyromagnetic Nonlinear Transmission Lines as Compact High Power Microwave Sources [online]. PhD thesis ed. Texas Tech University [viewed 9 July 2021]. Available from: http:// hdl.handle.net/2346/581995. KATAYEV, I. G., 1966. Electromagnetic shock waves. London: Illife Books Ltd.6. FURUYA, S., MATSUMOTO, H., FUKUDA, H., OHBOSHI, T., TAKANO, S. and IRISAWA, J., 2002. Simulation of Nonlinear Coaxial Line Using Ferrite Beads. Jpn. J. Appl. Phys. vol. 41, no. 11R, pp. 6536–6540. DOI: https://doi.org/10.1143/JJAP.41.65367. ROSTOV, V. V., BYKOV, N. M, BYKOV, D. N., KLIMOV, A. I., KOVALCHUK, O. B. and ROMANCHENKO, I. V., 2010. Generation of Subgigawatt RF Pulses in Nonlinear Transmission Lines. IEEE Trans. Plasma Sci. vol. 38, no. 10, p. 2681–2685. DOI: https://doi.org/10.1109/TPS.2010.20487228. AHN, J.-W., KARELIN, S. Y., KWON, H.-O., MAGDA, I. I. and SINITSIN, V. G., 2015. Exciting Yigh Frequency Oscillations in a Coaxial Transmission Line with a Magnetized Ferrite. J. Magn. vol. 20, no. 4, pp. 460–465. DOI: https://doi.org/10.4283/JMAG.2015.20.4.4609. KARELIN, S. Y., 2017. FDTD Analysis of Nonlinear Magnetized Ferrites: Application to Modeling Oscillations Forming in Coaxial Lines With Ferrite. Radiofis. Electron. vol. 8(22), no. 1, pp. 51–56. (in Russian). DOI: https://doi.org/10.15407/rej2017.01.05110. VESELOV, G. I. and RAYEVSKY, S. B., 1988. Layered metal-dielectric waveguides. Moscow, Russia: Radio i Svyaz’ Publ. (in Russian). Предмет і мета роботи: Наведено експериментальні результати й дані числового моделювання стосовно ефектів збудження мікрохвиль в коаксіальних лініях передачі, в котрі подаються однополярні високовольтні електричні імпульси. Метою роботи є з’ясування відносної важливості кількох механізмів, що можуть відповідати за виникнення мікрохвилевих коливань під час проходження імпульсу крізь хвилеводну структуру.Методи і методологія: Розглядаються дисперсійні та фільтрувальні властивості коаксіальних хвилеводів з трьома секціями, що є розташованими одна за одною вздовж осі симетрії структури. Дві ідентичні секції – на вході й на виході хвилевода – заповнені ізотропним рідким діелектриком, в той час як середня секція додатково заповнюється – або частково, або повністю – непровідним матеріалом з гіротропними властивостями. Вставлене ядро складається із набору феритових кілець, що характеризуються нелінійним відгуком на первинне високовольтне імпульсне збудження. У процессі вимірювань діаметри внутрішнього провідника та феритової вставки залишалися постійними. Діаметр зовнішнього провідника змінювався, аби проаналізувати вплив як власне цього розміру, так і ступеню заповнення перерізу феритом. Гіротропні властивості феромагнітного матеріалу реалізувалися завдяки накладанню поля магнітного зміщення від зовнішнього соленоїда. Вимірювання були проведені для різних значень імпульсної напруги в діапазоні сотень кіловольт при магнітних полях зміщення в десятки кілоампер на метр.Результати: В наших експериментах, як і в роботах інших авторів, спостерігалося, що однополярний імпульс, що заходить в лінію із радіально однорідної передньої секції, далі призводить до виникнення квазімонохроматичних коливань напруги. Вони виникають, як тільки імпульс пройде достатню дистанцію в радіально неоднорідній частині хвилевода. Такі осциляції можуть включати невелику кількість квазіперіодів, тобто мати значну ширину відповідної спектральної лінії. Шляхом належного вибору геометричних параметрів хвилеводної структури та характеристик первинного імпульсу можливо одержувати на виході коливання з частотою у декілька гігагерц і субгігаватним рівнем імпульсної потужності. Висновки: Частоти й амплітуди осциляцій, що виникають, а також їх спектральні ширини обумовлені комплексом дисперсійних і нелінійних властивостей хвилеводної структури. Набір хвилеводних мод, що можуть поширюватися в лінії, залежить від діаметрів внутрішнього й зовнішнього провідників коаксіальної лінії і діаметра феромагнітного включення з його власними дисперсійними властивостями. Осциляторна частина форми імпульсу може виникати й відокремлюватися від тіла імпульсу, якщо вона народжується на частоті, що є вищою за частоту відсічки для іншої моди, ніж первинна ТЕМ.Ключові слова: однополярний імпульс, коаксіальна лінія передачі, мікрохвилеві коливання, закони дисперсії, хвилеводні модиСтаття надійшла до редакції 10.08.2021Radio phys. radio astron. 2021, 26(3): 250-255REFERENCES1. DOLAN, J. E., 1999. Simulation of shock waves in ferriteloaded coaxial transmission lines with axial bias. J. Phys. D: Appl. Phys. vol. 32, no. 15, pp. 1826–1831. DOI: 10.1088/ 0022-3727/32/15/3102. GUBANOV, V. P., GUNIN, A. V., KOVALCHUK, O. B., KUTENKOV, V. O., ROMANCHENKO, I. V. and ROSTOV, V. V., 2009. Effective transformation of the energy of high-voltage pulses into high-frequency oscillations using a saturated-ferrite-loaded transmission line. Tech. Phys. Lett. vol. 35, is. 7, pp. 626–628. DOI: 10.1134/ S10637850090701163. VASELAAR, A., 2011. Experimentation and modeling of pulse sharpening and gyromagnetic precession within a nonlinear transmission line [online]. PhD thesis ed. Texas Tech University [viewed 8 July 2021]. Available from: http://hdl. handle.net/2346/ETD-TTU-2011-08-16634. REALE, D. V., 2013. Coaxial Ferrimagnetic Based Gyromagnetic Nonlinear Transmission Lines as Compact High Power Microwave Sources [online]. PhD thesis ed. Texas Tech University [viewed 9 July 2021]. Available from: http:// hdl.handle.net/2346/581995. KATAYEV, I. G., 1966. Electromagnetic shock waves. London: Illife Books Ltd.6. FURUYA, S., MATSUMOTO, H., FUKUDA, H., OHBOSHI, T., TAKANO, S. and IRISAWA, J., 2002. Simulation of Nonlinear Coaxial Line Using Ferrite Beads. Jpn. J. Appl. Phys. vol. 41, no. 11R, pp. 6536–6540.7. ROSTOV, V. V., BYKOV, N. M, BYKOV, D. N., KLIMOV, A. I., KOVALCHUK, O. B. and ROMANCHENKO, I. V., 2010. Generation of Subgigawatt RF Pulses in Nonlinear Transmission Lines. IEEE Trans. Plasma Sci. vol. 38, no. 10, р. 2681–2685. DOI: 10.1109/ TPS.2010.20487228. AHN, J.-W., KARELIN, S. Y., KWON, H.-O., MAGDA, I. I. and SINITSIN, V. G., 2015. Exciting Yigh Frequency Oscillations in a Coaxial Transmission Line with a Magnetized Ferrite. J. Magn. vol. 20, no. 4, pp. 460–465. DOI: 10.4283/ jmag.2015.20.4.4609. KARELIN, S. Y., 2017. FDTD Analysis of Nonlinear Magnetized Ferrites: Application to Modeling Oscillations Forming in Coaxial Lines With Ferrite. Radiofis. Electron. vol. 8(22), no. 1, pp. 51–56. (in Russian). DOI: 10.15407/ rej2017.01.05110. VESELOV, G. I. and RAYEVSKY, S. B., 1988. Layered metal-dielectric waveguides. Moscow, Russia: Radio i Svyaz’ Publ. (in Russian). Purpose: Experimental results and numerical simulations are presented, concerning effects of microwave generation in coaxial transmission lines which are fed with unipolar, high voltage electric pulses. The work is aimed at clarifying the relative importance of several mechanisms that could be responsible for the appearance of microwave-frequency oscillations in the course of pulse propagation through the guiding structure.Design/methodology/approach: Dispersive and filtering properties of coaxial waveguides that involve three structural sections are discussed. These latter follow one another along the axis of symmetry. Two identical sections at the input and output are filled with an isotropic liquid dielectric, while the middle part may, in addition, be either partially or fully filled with a non-conductive gyrotropic material. The inserted core represents a set of ferrite rings showing a nonlinear response to the initial high voltage, pulsed excitation. Throughout the series of measurements, the diameters of the inner conductor and of the ferrite core were kept constant. The outer conductor’s diameter was varied to permit analysis of the effect of that size proper and of the degree to which the cross-section is fi lled with ferrite. The gyrotropic properties of the ferrimagnetic material were realized through application of a magnetic bias field from an external coil. The measurements were made for a variety of pulsed voltage magnitudes from the range of hundreds of kilovolts, and magnetic bias fields of tens kiloamperes per meter.Findings: As observed in our experiments, as well as in papers by other writers, a unipolar pulse coming from the radially uniform front-end section, further on gives rise to quasi-monochromatic voltage oscillations. These appear as soon as the pulse has advanced a sufficient distance into the radially nonuniform portion of the guide. The oscillations may consist of a small number of quasi-periods, which suggests a large spectral line width. However, by properly selecting geometric parameters of the wave guiding line and the characteristics of the initial pulsed waveform it proves possible to obtain output frequencies of about units of gigahertz and pulse powers at subgigawatt levels.Conclusions: The frequencies and amplitudes of the appearing oscillations, as well as their spectral widths, are governed by the complex of dispersive and non-linear properties of the guiding structure. The diameters of the inner and outer coaxial conductors in the line, diameter of the ferrimagnetic insert and its intrinsic linear dispersion determine the set of waveguide modes capable of propagating through the line. An oscillating part of the waveform may appear and get separated from the main body of the pulse if it has originated at a higher frequency than the cut-off value for a different mode than the initial TEM.Key words: unipolar pulse, coaxial transmission line, microwave frequency oscillations, dispersion laws, waveguide modesManuscript submitted 10.08.2021Radio phys. radio astron. 2021, 26(3): 250-255REFERENCES1. DOLAN, J. E., 1999. Simulation of shock waves in ferriteloaded coaxial transmission lines with axial bias. J. Phys. Appl. Phys. vol. 32, no. 15, pp. 1826–1831. DOI: https://doi.org/10.1088/0022-3727/32/15/3102. GUBANOV, V. P., GUNIN, A. V., KOVALCHUK, O. B., KUTENKOV, V. O., ROMANCHENKO, I. V. and ROSTOV, V. V., 2009. Effective transformation of the energy of high-voltage pulses into high-frequency oscillations using a saturated-ferrite-loaded transmission line. Tech. Phys. Lett. vol. 35, is. 7, pp. 626–628. DOI: https://doi.org/10.1134/S10637850090701163. VASELAAR, A., 2011. 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Видавничий дім «Академперіодика» 2021-09-15 Article Article application/pdf http://rpra-journal.org.ua/index.php/ra/article/view/1362 10.15407/rpra26.03.250 РАДИОФИЗИКА И РАДИОАСТРОНОМИЯ; Vol 26, No 3 (2021); 250 RADIO PHYSICS AND RADIO ASTRONOMY; Vol 26, No 3 (2021); 250 РАДІОФІЗИКА І РАДІОАСТРОНОМІЯ; Vol 26, No 3 (2021); 250 2415-7007 1027-9636 10.15407/rpra26.03 en http://rpra-journal.org.ua/index.php/ra/article/view/1362/pdf Copyright (c) 2021 RADIO PHYSICS AND RADIO ASTRONOMY |