RADIO PHYSICS AND RADIO ASTRONOMY
type: channel
description: The Journal “Radio Physics and Radio Astronomy” (RPRA) is a peer-reviewed quarterly scientific journal of the National Academy of Sciences of Ukraine. RPRA was established in 1995. State Registration Certificate for printing mass media is КВ №1231, 02.02.1995; re-registration: КВ 25208-15148 ПР from 20.07.2022 ISSN 2415-7007 (Online) ISSN 1027-9636 (Print) Abbreviated key title: Radio phys. radio astron. DOI: https://doi.org/10.15407/rpra URL: http://rpra-journal.org.uа Language of publishing: Ukrainian, English Founders: The National Academy of Sciences of Ukraine Institute of Radio Astronomy of the National Academy of Sciences of Ukraine O. Ya. Usikov Institute for Radiophysics and Electronics of the National Academy of Sciences of Ukraine Publisher: The NAS-Ukraine Academperiodyka Publishing House The NAS-Ukraine Academperiodyka Publishing House replicates the RPRA within the NAS-Ukraine Journal Support Program. RPRA publishes papers, brief information and letters to the editors relating to the modern problems of radio physics, radio astronomy and astrophysics, containing the results of fundamental and applied researches, description of research methods, hardware implementation and practical application, as well as current information such as comments, events, men of science. The RPRA is included into the List of scientific professional editions of Ukraine, approved by the Decree No. 582 of 24.04.2024 of the Ministry of Education and Science of Ukraine, in which the results of Ph.D. and Doctoral theses (in physics and mathematics) are recommended to be published. Current Issue Volume 31, No.2 (2026) CONTENT
publisher: Видавничий дім «Академперіодика»
language: en-US
publication name: RADIO PHYSICS AND RADIO ASTRONOMY
issn: 1027-9636
copyright: Since April 2018, all papers in RPRA are published under the terms of the Creative Commons Attribution 4.0 International (CC-BY) License with the authors retaining a copyright to their papers. This license permits anyone to copy, distribute, spread, and adapt the paper content, without obtaining permission from the author(s) or the Journal, provided the proper acknowledgement of the work used authorship and initial publication in this journal. Please see the full license terms and requirements at https://creativecommons.org/licenses/by/4.0/ The authors of the papers published prior to December 2018, have granted the Journal the right of the first publication and retain the copyright as the owners of the manuscript.
items: 70 YEARS OF LOW-FREQUENCY RADIO ASTRONOMY IN UKRAINE
items: COMPUTATIONAL EFFICIENCY OF AN ARTIFICIAL NEURAL NETWORK IN OPTIMIZING THE OPERATING CONDITIONS OF PATCH ANTENNAS
items: A COMPARATIVE ANALYSIS OF RADIATION FROM CIRCULAR AND RECTANGULAR APERTURES: LIMITATIONS ON THEIR USE FOR BESSEL BEAM FORMATION
items: MANIPULATION OF SPATIAL FIELD DISTRIBUTION IN A PLANAR MICROWAVE PHOTON-MAGNON CONVERTER
items: SPATIAL DYNAMICS OF THE RADIALLY POLARIZED VORTEX BEAMS OF TERAHERTZ-RANGE RADIATION SUBJECTED TO TIGHT FOCUSING
items: Aleksei A. Kostenko (to the 80th birth anniversary)

70 YEARS OF LOW-FREQUENCY RADIO ASTRONOMY IN UKRAINE
type: item
description: Subject and Purpose. The article is devoted to the birth and seventy years of successful development of low-frequency radio astronomy in Ukraine. This activity was started in the mid-50s of the prior century by the outstanding Ukrainian scientist Academician Semen Yakovych Braude with the maximum support of the also unique personality of the President of the NAS of Ukraine Boris Yevgenovych Paton. The creation of the world’s largest low-frequency radio telescopes and interferometers UTR-2 and URAN, the birth of a galaxy of outstanding scientists and a widely known radio astronomy school proved the highest world level of domestic physical, mathematical and technical sciences. The purpose of the work is a historical and scientific review of low-frequency radio astronomy in Ukraine and the income of S.Ya. Braude in its foundation. Methods and Methodology. All stages of the creation of domestic experimental base of radio astronomy on decameter-me- ter waves are analyzed in comparison with world experience. The astrophysical advantages of low-frequency radio astronomy, methodological difficulties of observations in this range and means of overcoming them are revealed. This is done on the example of the creation and use for 70 years of radio telescopes UTR-2, URAN, GURT. Results. The world’s largest low-frequency radio telescopes have been created, which are the national scientific heritage of the country. Constant innovative modernization of observation tools and methods has allowed us to obtain a large number of priority results recognized by the international community, and has made the contribution of Ukrainian scientists an import- ant component of complex highly sensitive radio astronomy research. Conclusions. For 70 years, low-frequency radio astronomy has been a priority area of research at the National Academy of Sciences of Ukraine. The scientific school created by the outstanding scientist, Academician S.Ya. Braude, is a significant con- tribution to domestic a…
creator: O. O. Konovalenko
creator: V. V. Zakharenko
creator: O. M. Ulyanov
creator: L. I. Gurvits
creator: I. B. Vavilova
creator: Ya. S. Yatskiv
creator: P. L. Tokarsky
creator: O. O. Stanislavsky
creator: I. M. Bubnov
creator: M. M. Kalinichenko
creator: S. V. Stepkin
creator: M. A. Sydorchuk
creator: E. V. Vasylkivskyi
creator: O. M. Reznichenko
creator: M. V. Shevchuk
creator: L. O. Stanislavsky
creator: S. M. Yerin
creator: V. O. Shepelev
creator: V. V. Dorovskii
rights: Copyright (c) 2026 RADIO PHYSICS AND RADIO ASTRONOMY
date: 2026-06-16
publication date: 2026-06-16
volume: 31
number: 2
starting page: 75
doi: 10.15407/rpra31.02.075

COMPUTATIONAL EFFICIENCY OF AN ARTIFICIAL NEURAL NETWORK IN OPTIMIZING THE OPERATING CONDITIONS OF PATCH ANTENNAS
type: item
description: Subject and Purpose. Designing antennas with desired operational features is a complex optimization problem addressing a large number of parameters and nonlinear relationships. Artificial neural networks (ANNs) have had strong potential in antenna engineering. The ability to approximate nonlinear functions and capture hidden relationships enables partial automation of antenna designing. However, it requires a detailed analysis of how ANN parameters affect predictive accuracy and computational efficiency. The present study investigates the influence of ANN architecture and training configurations on the predictive accuracy of resonant frequencies for rectangular microstrip patch antennas. Methods and Methodology. A modular Python-based experimental platform is used to evaluate ANN performance for dif- ferent ANN configurations. The ANN training is on a synthetic dataset generated from a classical analytical antenna model. The number of hidden layers, neurons per layer, activation functions, and optimizers are systematically varied to assess their particular impacts on convergence, generalization performance, and execution time. Results. It has been shown that a three-layer neural network [1024, 512, 256 neurons] with ReLU activation and the Adam optimizer strikes the best balance between predictive accuracy and training rate. Simpler or excessively deep architectures, non-adaptive optimizers, and saturating activation functions can slow convergence or cause unstable training. Further analysis indicated that a smaller batch size introduces useful stochasticity into training but might also destabilize the process. Conclusions. The study has demonstrated that joint optimization of ANN architecture and training dynamics is essential for developing accurate and computationally efficient electromagnetic models. The practical results are recommendations for machine-learning-based antenna design. Keywords: artificial neural network (ANN), activation function, adaptive optimi…
creator: S. Butov
creator: A. Tuz
creator: O. Morozova
creator: S. Vinnichenko
creator: O. Khardikov
creator: S. Shulga
rights: Copyright (c) 2026 RADIO PHYSICS AND RADIO ASTRONOMY
date: 2026-06-16
publication date: 2026-06-16
volume: 31
number: 2
starting page: 98
doi: 10.15407/rpra31.02.098

A COMPARATIVE ANALYSIS OF RADIATION FROM CIRCULAR AND RECTANGULAR APERTURES: LIMITATIONS ON THEIR USE FOR BESSEL BEAM FORMATION
type: item
description: Subject and Purpose. Essentials of the processes for millimeter-wavelength radiation from circular apertures are analyzed, with emphasis on the formation of the field’s radiation pattern (RP) and modal structure in the aperture. The work is aimed at obtaining analytical expressions for the circular aperture’s RP and verifying these in experiments. Further aims include investi- gation of radiation characteristics and possibilities for forming up specific types of wave beams for applications like medicine, communications and interaction with aerial vehicles. Also, possible techniques of Bessel beam generation are investigated for the millimeter-wavelength range. Methods and Methodology. The electromagnetic field distribution over the waveguide aperture is assumed to be available for determining its radiated field in free space. The far-field characteristics are calculated via Kirchhoff ’s integral taken over the aperture and verified experimentally by measuring the RP and the voltage standing wave ratio (VSWR) in the wave guiding channel. Results. Explicit expressions for the RP of a circular aperture have been derived, with the use of pattern functions, for two mutually orthogonal planes. Measurements at a frequency of 34 GHz revealed that a circular aperture of a 30 mm diameter provided for a voltage standing wave ratio (VSWR) in the guiding channel close to 1.0558. The calculated and measured cross section areas of the RP, as estimated for the planes of the E and H field vectors, coincide with a Gaussian distribution to the level of −8.7 dB. The RPs produced by apertures of circular and rectangular cross-sections have been compared for antennas of equal maximum sizes. Conclusions. Analytical expressions have been derived for the radiation pattern (RP) of a circular aperture supporting the TE11 mode in two mutually orthogonal planes. As has been found, such an aperture cannot provide for formation of the far- field electric distribution required for generating a Bes…
creator: I. K. Kuzmychov
creator: O. A. Voitovych
creator: O. S. Lukash
creator: E. M. Khutorian
creator: V. P. Maltsev
creator: O. V. May
rights: Copyright (c) 2026 RADIO PHYSICS AND RADIO ASTRONOMY
date: 2026-06-16
publication date: 2026-06-16
volume: 31
number: 2
starting page: 108
doi: 10.15407/rpra31.02.108

MANIPULATION OF SPATIAL FIELD DISTRIBUTION IN A PLANAR MICROWAVE PHOTON-MAGNON CONVERTER
type: item
description: Subject and Purpose. The research addresses planar photon-magnon (P-M) converters that efficiently convert between microwave photons and magnons and are essential components in emerging quantum technologies. Planar P-M converters benefit particularly from planar, two-dimensional (2D) resonators. Among them are asterisk-shaped resonators featuring compact geometry and strong concentration of the magnetic component of the electromagnetic (EM) field. The present work seeks an effective approach to optimizing planar P-M converters to enhance conversion efficiency and further miniaturize the device by manipulating the spatial distribution of the high-frequency magnetic field. Methods and Methodology. The proposed approach relies on numerical simulations of the electrodynamic response of the asterisk-shaped resonator coupled to the feeding microstrip line. Families of the resonance spectra are analyzed as a function of the resonator’s position relative to the microstrip line, which effectively varies the electromagnetic coupling strength. This methodology allows systematic optimization of the resonator’s geometrical and spectral parameters, enabling targeted manipulation of the magnetic field distribution across the magnetic sample location. Results. The conducted analysis has demonstrated that a fine adjustment of the P-M coupling strength can maximize the concentration of the magnetic component of the high-frequency EM field at a desired location within the resonator. Practical recommendations have been developed for designing high-performance planar P-M converters, offering a framework for the efficient integration of asterisk-shaped resonators into miniaturized quantum devices. Conclusions. Based on the numerical analysis of the spectral properties of a 2D asterisk-shaped split-ring resonator (ASRR) intended for a planar microwave P-M converter, it has been shown that selecting the optimal position for the feeding microstrip line allows a high concentration of the mag…
creator: S. Yu. Polevoy
creator: T. Bozkurt
creator: B. Rami
creator: S. I. Tarapov
rights: Copyright (c) 2026 RADIO PHYSICS AND RADIO ASTRONOMY
date: 2026-06-16
publication date: 2026-06-16
volume: 31
number: 2
starting page: 119
doi: 10.15407/rpra31.02.119

SPATIAL DYNAMICS OF THE RADIALLY POLARIZED VORTEX BEAMS OF TERAHERTZ-RANGE RADIATION SUBJECTED TO TIGHT FOCUSING
type: item
description: Subject and Purpose. The paper concerns the effect of tight focusing of the terahertz-range vortex laser beams, formed byradially polarized TM0m modes of a dielectric waveguide-based resonator, that results from beam’s passage through a spiral phase changing plate. The work is aimed at obtaining analytical expressions to describe the field structure and determine the effect exerted by the topological charge of the plate, as well as order of the participating mode, upon the spatial-energy characteristics of the radiation within the lense’s focal region. Methods and Methodology. The propagation and focusing of the radiation are described within the framework of the Rayleigh-Sommerfeld vector theory, making use of a nonparaxial approximation. The mode structure of the resonant cavity is determined by the TM01, TM02 and TM03 modes of a hollow circular dielectric waveguide. The action of the spiral phase changing plate is taken into account in terms of a complex-valued transfer function using topological charge numbers n=0, 1, 2. Results. Analytical expressions have been obtained for components of the electric field of the laser beams as excited by the radially polarized TM0m modes passing through the spiral phase changing plate during their tight focusing. As has been found, in the absence of a phase-changing plate in the focal region of the lens, an annular field structure with a non-zero axial field’s intensity is preserved for all the modes involved. When using a phase plate with a topological charge n= 1 the field intensity maxima are localized near the axis, while in the case of n=2 an annular field distribution with a zero intensity at the axis is restored. The highest magnitudes of the maximum field intensity for the modes TM01, TM02 and TM03 correspond to the topological charge n= 1. In the case of a phase-changing plate with n=1, the phase fronts of all the three field components of the modes under study acquire a single-lobe vortex structure, while with n= 2 —…
creator: A. V. Degtyarev
creator: M. M. Dubinin
creator: V. A. Maslov
creator: Y. S. Pronin
rights: Copyright (c) 2026 RADIO PHYSICS AND RADIO ASTRONOMY
date: 2026-06-16
publication date: 2026-06-16
volume: 31
number: 2
starting page: 126
doi: 10.15407/rpra31.02.126

Aleksei A. Kostenko (to the 80th birth anniversary)
type: item
rights: Copyright (c) 2026 RADIO PHYSICS AND RADIO ASTRONOMY
date: 2026-06-16
publication date: 2026-06-16
volume: 31
number: 2