Radio physics and electronics

3-15

Authors: N.P. Yeliseyeva, S.L. Berdnik, V.A. Katrich

Subject and Purpose. A resonant monopole of an electrical length 0.2 £ l / l £ 0.3 mounted on an infinite, perfectly conducting plane or on a rectangular, perfectly conducting screen is considered. The objective is to determine how the radiation resistance, surface impedance, and input impedance depend on the length and thickness of the resonant monopole and how the screen size affects the resonant characteristics and directive gain of the impedance monopole. Methods and methodology. A three-dimensional vector problem of the field diffraction of an impedance monopole mounted on a perfectly conducting rectangular screen is solved using the method of uniform geometrical theory of diffraction and adopting asymptotic expressions of the diffracted fields and electric currents of a thin impedance dipole located in the free space. Results. Taking into account diffraction effects at the edges of the square screen, the resonant values of the surface impedance of the monopoles and the corresponding radiation resistance and directive gain have been calculated subject to the condition that the electric field amplitude is at its maximum. It has been found that as the screen size exceeds the two wavelengths, the edge phenomena have little effect on the monopole resonant characteristics. The radiation resistance reaches its maximum when the side of the square screen is as long as L / l = 0.9…0.95. The first maximum of the directive gain occurs at L / l = 1.2…1.3. The obtained results have been verified with the aid of the computational electromagnetics software FEKO. Conclusion. A three-dimensional vector diffraction problem has been solved for an impedance monopole mounted on an ideally conducting, rectangular screen. Algorithms and computational programs have been developed to determine resonant characteristics and radiation patterns of the radiating system. By choosing an optimum screen size it is possible to increase the directive gain of an impedance monopole of the length l = 0,2l by 24% and the radiation resistance by 38% compared to the infinite screen.

26-33

Authors: A.S. Bryukhovetski, A.V. Vichkan’

Subject and Purpose. The wave field produced by a spatial-temporal distribution of sound sources in a uniform subsonic flow is theoretically studied in an effort to obtain an analytical dependence of the sound field on physical parameters. Method and Methodology. Cauchy problem for wave equation in a moving medium is solved using a spatial-waveguide Fourier expansion of the sound field. A Fourier representation of the Green's function of a point-like pulse sound source is constructed whose inverse transform allows us to obtain the Green's function spatial-temporary representation. Results. With the Green’s function obtained, the wave fields from arbitrarily shaped sources have been represented in the “wave potential” form, which is a convolution type integral of the density of spatial-temporal distribution of the sound sources and the Green’s function. Conclusion. The calculation results give a clear idea of the propagation of sound waves excited by a point-like pulse source in a uniform homogeneous flow. The wave front of the sound field represents a sphere whose center “drifts” from the source at a speed equal to the speed of the flow in its movement direction, and the radius of the sphere grows in the course of time at a speed equal to the speed of sound. The obtained Green’s function allows for the analytic continuation to the supersonic flow case that, in contrast to the subsonic case, satisfies the causality principle not in all unlimited space but only at the observation points within the Mach cone. The wave field from a monochromatic source is the limiting case of the rectangular pulse solution.

42-53

Authors: V. N. Derkach, E. A. Alekseev, R. V. Golovashchenko, Ye. M. Ostryzhnyi, A. A. Meshcheryakov, S. I. Tarapov

Subject and Purpose. The subject of the study is spectral and energy characteristics of whispering-gallery disk resonators made up of low-loss microwave dielectric and semiconductor materials, namely, gold-doped silicon Si:Au, Chemical Vapor Deposition (CVD) diamond, Arc Plasma Jet (APJ) diamond, and alumina ceramics Al2O3. On the basis of the temperature dependences of the microwave energy loss in the materials mentioned, we seek to classify the loss contributions among the electromagnetic energy absorption mechanisms and find physical parameters responsible for these mechanisms. Methods and Methodology. The loss values were experimentally obtained by the whispering-gallery disk resonator technique with the usage of a cryodielectrometer. A phenomenological simulation was performed to classify the loss contributions to the temperature dependence of electromagnetic energy absorption among the major loss mechanisms in the examined materials. Results. The experimental study results on the dielectric loss temperature dependence within 4.2...300 K have been presented and discussed for low-loss semiconductor and dielectric materials, including gold-doped silicon Si:Au, CVD-diamond, APJ-diamond, and alumina ceramics Al2O3 with reference to the frequency band 110...140 GHz. Certain design features have been suggested to use in the authors’ software-controlled measuring unit to provide the interchangeability of backward wave tubes (BWT) inside the cryodielectrometer and extend the merasuring bandwidth up to 34...144 GHz. The unit offers software-controlled frequency tuning with a spectral resolution of about 0.1 MHz. The loss contributions have been classified among the major loss mechanisms, and physical constitutive parameters responsible for these mechanisms have been determined. Conclusion. The temperature dependences of dielectric loss in low-absorption materials have been registered and analysed. The developed measuring unit has advantageous design features and provides, in addition, an independent controllable radiation source which can be included in a frequency synthesis system with phase-locked loop.

60-67

Authors: Yu.V. Kornienko, I. Liashenko, V.V. Pugach, S.I. Skuratovskiy

Subject and Purpose. The influence of Earth’s atmosphere leads to significant distortion of object images obtained with Earth-based instruments. In this case, the distortion of the Fourier component phase plays a far more important role than the module distortion. The influence of Earth’s atmosphere on the Fourier component phase may be considered as a multiplicative noise in the frequency domain. For combatting this influence, we propose signal accumulation, implying that total phases rather than their main values, which are available for the direct measurements by experiment, should be accumulated. The features of the proposed total phase accumulation method are studied in the present paper. Methods and Methodology. The current studies depend on computer experiment and theoretical analysis of the obtained results. The performance efficiency of the total phase accumulation method is evaluated with the aid of the computer system of astronomical image modeling and processing developed in the O.Ya. Usikov IRE of NASU. Results. A relationship has been obtained between the error of image reconstruction by the total phase accumulation method and the number of the accumulated images in different observation conditions. The dependence has a non-monotonic behavior, which remains to be investigated. Conclusion. That the reconstruction error dependence in the total phase accumulation method has a minimum is important for the practical method application as there comes an accumulation point after which the reconstruction accuracy degrades. The location of that minimum depends on the atmospheric parameters, sending us in search of a criterion for choosing an optimal sequence length of image accumulation.

78-88

Authors: A.D. Yegorov, S.A. Yegorov, V.A. Yegorov, I.E. Sinelnikov

Subject and Purpose. The subject of the work is atomic emission spectral analysis of substances using the most affordable arc and spark sources widely accepted in both laboratory and industrial practice. The aim is to improve solution principles of some technical problems in the field of construction of power supplies of arc and spark discharges with predetermined properties and to study their parameters. Methods and Methodology. Traditional methods of producing spark and arc discharges are used. Several designs are proposed for discharge current and discharge gap breakdown power supplies, modeled using a computer program of circuit simulation and tested on the existing prototypes. The developed generator was put through tests and compared with a production analog of it in terms of statistical analysis of spectrum measurement results. Results. The microprocessor-controlled arc plasma generator "TsUG-2" has been developed and performed. The discharge current generation unit was constructed on the principle of digital-to-analog converter (DAC) with current summation. The discharge gap breakdown unit was performed on the semiconductor circuitry basis without any gas spark gaps. A unit was added for generating the initial pulse of discharge current, which made it possible to extend the spectrum excitation range, provide the sampling process control and improve the discharge combustion stability. A parameter control unit was developed to create and maintain the protective gas environment in the discharge chamber. The control over the operating modes of the generator and its synchronization with the spectrum recording equipment is exerted through an external interface. The manual control is carried out via a stand-alone control panel. The created generator "TsUG-2" produces discharge gap breakdown pulses of up to 12 kV amplitudes and arc pulses spanning a discharge current range as wide as 1...47 A. On them, additional current pulses of up to 150 A amplitudes can be superimposed, which significantly increases the rate of discharge current rise. The highest frequency of the discharge excitation pulses is 800 Hz. Comparison tests of the developed generator "TsUG-2" and a production generator "UGE-4" have been carried out. Conclusion. The measurement results show that the standard deviation (RMS) of the photometric data of plasma formations obtained from the developed arc plasma generator "TsUG-2" is, on the average, three times less than from a production generator "UGE-4.

3-8

Authors: N.N. Beletskii, S.A. Borysenko

Subject and Purpose. The effect of total electromagnetic wave tunneling through a three-layer structure containing a plasma-like negative-permittivity layer is important for both gaining a better insight into the high-frequency properties of layered solids and, hence, creating new types of high-frequency radio-physical devices. The main purpose is to study the influence the frequency dispersion of the negative-permittivity layer exerts on the electromagnetic wave tunneling through a three-layer structure with an asymmetric dielectric medium. Methods and Methodology. A new universal approach is used, based on introducing dimensionless frequencies and dimensionless layer thicknesses of a three-layer structure. It allows the frequency-dependent conditions of the effect of total electromagnetic wave tunneling to be examined for different frequency ranges and various three-layer structure parameters. Results. It has been shown that taking into account the frequency dispersion of the negative-permittivity layer makes it possible to observe the total tunneling of electromagnetic waves at different frequencies with an appropriate choice of the three-layer structure parameters. In various frequency ranges, the effect of two-frequency total tunneling of electromagnetic waves has been predicted. Conclusion. In the presence of a frequency dispersion of a negative-permittivity layer as part of a three-layer structure, the total electromagnetic wave tunneling conditions of this structure are softened and modified significantly. In this case, unique phenomena arise that can be used to create fundamentally new high-frequency devices in optics, radiophysics, and electronics.

22-28

Authors: V.A. Kabanov

Subject and Purpose. One of the relevant areas of remote sensing of the environment is the development of microwave methods of passive sensing of the atmosphere. The biggest challenge occurring in radiometric measurements is measuring system calibration. The reason lies in the lack of external calibration elements whose brightness temperatures are known with a high accuracy. The paper deals with the method for determining the sky brightness temperature by relative measurements at different elevation angles. The brightness temperatures refined in the way fit for radiometric system calibration. Methods and Methodology. Basically, the approach is governed by the dependence of the atmospheric brightness temperature on the elevation angle in terms of the plane-layered isothermal atmospheric model. The measurements rely on a three-centimeter radiometric system having a horn-reflector antenna combined with the MPL-1 weather radar, the entire range of elevation angles being accessible. Besides, a combined setup of two, 10 GHz and 36 GHz, radiometers is involved for measurements from a building window. Results. The previously proposed methodology for radiometric system calibration against the sky temperature obtained by relative measurements at different elevation angles has been analyzed and tested. The calibration possibility has been examined in the case that zenith measurements are unavailable. Conclusion. The proposed method for getting sky temperatures upon relative measurements at different elevation angles significantly increases accuracy of radiometric system calibration and extends a range of weather conditions admitting calibration of the kind. It has been shown that the radiometric system calibration against the sky temperature is possible even with zenith measurements excluded.

38-45

Authors: T.V. Kalmykova, S.I. Tarapov, A.S. Vakula, S.V. Gorobets, O.Yu. Gorobets, Yu.I. Gorobets, M.A. Bulaevskaya, K.A. Getmanenko

Subject and Purpose. Synthesis of biological sorbents has become one of the ways to solve the problem of environment contamination with heavy metals. Today, studying properties of biosorbents with injection of magnetic nanoparticles is important. Thus, injection of magnetic nanoparticles of magnetite (Fe3O4) improves absorption properties of biosorbents. The subject of the present work is magnetic resonance properties of nanoparticles inside biosorbents, such as macromycetes like Pleurotus ostreatus. The purpose is to examine these magnetic resonance properties and analyze the state of magnetite nanoparticles inside Pleurotus ostreatus. Methods and Methodology. The X-band Electron Spin Resonance (ESR) method is employed to register ferromagnetic resonance (FMR) spectra at T = 294 K. TEM-images of magnetic nanoparticles are made in the transmission electron microscope. Mathematical modeling for the properties of the arising clusters of magnetic Fe3O4 nanoparticles inside macromycetes Pleurotus ostreatus is performed using a phenomenological model upon the well-known Kittel equation. A model enhancement is proposed in the case of interacting nanoparticles inside an ellipsoidal magnetic cluster. Results. It has been shown that Fe3O4 nanoparticles are well absorbed by macromycetes and gather into structural clusters regardless of the concentration of magnetic nanoparticles injected. These magnetic clusters of magnetic nanoparticles have ellipsoidal shapes with an aspect ratio of 3:1:1. The developed mathematical model makes it possible to obtain dimensions of magnetic clusters from the FMR spectra and evaluate their shape and mutual magnetic interaction. The mathematical modeling results are in good agreement with TEM-images of these clusters inside Pleurotus ostreatus. As a result of modeling are in good agreement with the TEM-images of these clusters inside Pleurotus ostreatus. Conclusion. The presented results will contribute to the development of non-destructive testing of the state of biological sorbents using magnetic resonance radio spectroscopy methods.

54-63

Authors: A.V. Degtyarev, M.M. Dubinin, V.A. Maslov, V.S. Senyuta

Subject and Purpose. In this paper, spatial power characteristics of laser beams with inhomogeneous spatial polarization are theoretically investigated depending on whether they have moderate or sharp focusing. The spotlight of the numerical simulation of laser beam focusing in the terahertz range is on the laser waveguide dielectric resonator modes coincident with waveguide eigenmodes. Symmetric and asymmetric modes with both spatially inhomogeneous azimuthal and radial polarizations and homogeneous linear polarization of the field are considered. Methods and Methodology. The study of the electric field components of laser radiation beams in their free space propagation employs Rayleigh-Sommerfeld integrals in nonparaxial approximation. The focusing lens action on the laser radiation is considered using the amplitude-phase correction function. The total intensity distributions of the resonator modes and their particular field components in the lens focal area are examined. Results. Wave beams with inhomogeneous spatial polarization of radiation are needed for meeting important fundamental and applied problems concerning terahertz electromagnetic wave interaction with matter and including diagnostics of material surface, thin films and biological objects, design and development of terahertz systems of information transmission and processing, terahertz communication systems, achievement of subwave resolution in terahertz tomography, etc. The literature on pulsed radiation beam focusing in the terahertz region is available, which cannot be said about continuous radiation beam focusing, data on the subject being practically absent. In the present work, physical features of moderate and sharp focusing of laser beams have been theoretically studied in the case of their excitation by modes of the resonator with a circular dielectric waveguide with different spatial polarizations of the field. The obtained results give a more in-depth view of the focusing features of terahertz laser beams. Conclusions. Physical features have been established for spatial power characteristics of radiation beams with different spatial polarizations of the field in the case of the excitation by modes of the laser cavity upon a circular dielectric waveguide in the terahertz range and with the regimes of moderate and sharp beam focusing in the free space considered.

74-81

Authors: O.V. Holovan, V.M. Kharchenko

Subject and Purpose. The paper presents a technology of constructing a promising meteor-burst communication system (MBCS) with code division multiplexing. It increases the bandwidth and improves the noise immunity and covert operation of the system. Methods and Methodology. The proposed technology is based on software-defined radio (SDR) and provides MBCS adaptation to the environment conditions by means of software parameter control of the signals and their transfer protocols. It includes a technique of forming a large ensemble of signals with a direct sequence spread spectrum and improved auto- and cross-correlation properties, involves the optimal reception and matched digital filtering of large-base signals. In order to improve the noise immunity, the narrow-band interference rejection in the signal spectrum is proposed and is jointly software installed with the matched filtering. The detection and synchronization techniques effectively working in the non-Gaussian and non-stationary interference conditions gained consideration. Results. A method of forming a large ensemble of direct sequence spread spectrum signals with improved auto- and cross-correlation properties has been software implemented using a pseudorandom permutation of codeword elements of a maximum-length register code. Designed with the use of fast Fourier transforms, algorithms of digital matched filtering and interference rejection as applied to large-base signals have been implemented via field-programmable gate arrays (FPGA). A method of detection and synchronization of large-base signals has been proposed and software implemented on the FPGA basis. Conclusion. The proposed algorithms and their implementation methods make it possible to increase the bandwidth, improve noise immunity and enhance covert operation of the meteor-burst communication system with code division multiplexing.

3-10

Authors: L.P. Mospan, А.А. Kirilenko, D.Yu. Kulik, S.О. Steshenko

Subject and Purpose. Peculiarities of the electromagnetic wave scattering at screens perforated by U-shaped slots are the subject of the paper. Numerical modeling of frequency-selective surfaces with frequency characteristics given and research into the possibilities of the performance control of the screens by complicating their elementary cell geometry are the purposes of the paper. Method and Methodology. The numerical modeling is performed upon the MWD3 software package developed in the laboratory of computational electromagnetics of the IRE NASU. Based on the scattering mode technique and the mode-matching technique taking into account the electromagnetic field behavior near the edges, this software package enables calculations of scattering characteristics of both compound waveguides and gratings with piece-wise boundaries. Results. A virtual waveguide was incorporated into the MWD3 projection schemes, extending capabilities of the MWD3 software and making it possible to treat the frequency-selective surfaces with piece-wise boundaries without adding new building blocks. Numerical modeling of perforated screens with U-shaped slots was carried out. Conclusion. Configurations of single and double metal screens and, also, a compound grating formed by two screens separated by a dielectric layer were calculated in full agreement with the given task. The perforated screens provide essential reflectivity decrease at low frequencies and, also, a low insertion loss level in the given millimeter wave region. The obtained results can be of interest for specialists in antenna-feeder engineering and for MWD3 software users.

21-27

Authors: D.M. Bychkov, V.K. Ivanov, A.Ya. Matveev, V.N. Tsymbal, S.E. Yatsevich

Subject and purpose. The purpose of this work is to study the effect of wind on the anomalous scattering of radio waves during aeolian processes of sand and dust transporting. Мethods and methodology. The article analyzes the spatial variations of the near-surface wind and their effect on the characteristics of anomalously narrowly directed radio wave backscattering according to the long-term studies of desert regions of Al-Jouf, Akshar and Trarza in Mauritania by Envisat-1 satellite SAR. Results. Analysis of SAR data indicates that intensity of radio wave scattering on the leeward slopes of sand ridges is more than 12...15 dB higher than the one from the slopes located in the "wind shadow" zone, which indicates the direct influence of the surface wind on the back scattering of radio waves during aeolian sand and dust transportation. The dependences of changes in the backscattering coefficient s 0 on the angle of local irradiation q along sections of fragments of homogeneous sections of the surface radar images are obtained. Conclusion. SAR data indicate that the spatial distribution of the maximum intensity values of anomalously narrowly directed backscattering of radio waves corresponds to the spatial distribution of the near-surface wind. The intensity of backscattering of radio waves, starting at a speed of 2 m/s and higher, steadily depends on the wind speed.

38-49

Authors: M.V. Balaban, Y.V. Goncharenko, V.M. Gorobets, O.L. Kovorotniy, F.V. Kivva, G. Farquharson

Subject and Purpose. The paper is concerned with Synthetic Aperture Radar (SAR) imaging and data processing and seeks to modify the conventional time-domain back projection algorithm (BPA) used for creating a SAR image. The modification consists in the radar squint-angle control at the stage of data processing. Methods and Methodology. Mathematical modeling methods are used. The modeling results are verified by reference to the experimental data. Results. A modification proposed for the back projection algorithm (BPA) enables fast-moving targets to be detected on a stationary image created by synthetic-aperture squint-angle side-looking radar. The back projection algorithm with the squint angle control was experimentally verified by a speedboat example to show that the SAR image has signatures of fast-moving targets which are not observed on the image formed by the classic back projection algorithm. Conclusion. The proposed modification of the back projection algorithm improves the detection probability of fast-moving targets on a SAR image and does it without any complication of the classic back projection algorithm or additional computing time.

60-69

Authors: Yu.O. Averkov, Yu.V. Prokopenko, V.M. Yakovenko

Subject and Purpose. The creation of millimeter and submillimeter electromagnetic wave generators is a promising direction in radio physics. These generators are demanded in medicine, biology, spectroscopy, broadband wireless communications and other branches of science and technology. One of the ways of millimeter and submillimeter wave generation is interaction between charged-particle beams and super-dimensional electrodynamic structures in multimode operation. In this regard, elementary physical mechanisms underlying this interaction invite further investigation. In the paper, the problem of spatial-surface eigenmode excitation is considered for a solid-state cylinder when a nonrelativistic electron moves in a vacuum over the surface of this cylinder and parallel to its axis. Because of the nonrelativistic character of the electron motion, the electron field and the radiation field in a vacuum are treated in the electrostatic approximation, while the fields inside the cylinder are calculated with the delay effect taken into account. Methods and Methodology. Maxwell’s equations in space-time field terms yield an analytical expression of the electron energy loss for the spatial-surface eigenmode excitation of a dielectric cylinder. This expression is numerically analyzed using the bisection method to find roots of the dispersion equation. Results. The analysis of the electron energy loss suggests that the E-type modes are the most efficiently excited. The electron energy loss for the E-mode excitation is approximately two orders higher than the loss for the excitation of H-modes with the same azimuthal and radial mode indices. The largest electron energy loss corresponds to the HE11 mode excitation. Conclusion. The performed study gives a deeper insight into the physical mechanism underlying the eigenmode excitation of a dielectric cylinder under the action of charged particles. The obtained results can be generalized to the case of a multijet electron beam used to generate whispering-gallery electromagnetic modes.

80-85

Authors: M.А. Miliaiev, S.V. Nedukh, S.I. Tarapov

Subject and Purpose. The paper presents the development and testing of a microwave splitter based on a planar hyperbolic metamaterial with a structural defect. The planar hyperbolic metamaterial is so constructed that a propagating electromagnetic (EM) wave is channeled in a certain direction depending on the metamaterial parameters. The wave splitting is possible where a part of the incident wave is reflected from a defect created inside the metamaterial. As the defect spatial orientation relative to the incident EM wave changes, the propagation direction of the reflected EM wave also changes. By this means the wave propagation control can be implemented in the considered splitter. Methods and Methodology. A defect in a planar hyperbolic metamaterial is created using the circuit theory that relates the material parameters to the equivalent unit-cell capacitances and inductances which, in turn, depend on the parameters of the microstrip line and capacitors. Thus, a change in any parameter of the circuit inside the unit cell changes its material parameters and makes a defect cell. In this work, a defect is created by changing the capacitance of the capacitors in a given set of elementary cells of a planar hyperbolic metamaterial, controlling thereby the size of the defect and its spatial location relative to the propagating wave. The numerical model of EM wave propagation inside a planar hyperbolic metamaterial with a defect is validated by experiment. In it, the field distribution over the metamaterial surface is obtained using the active probe method in the three cases: a defect-free metamaterial and two variants of defect orientation. To insert the electronic control, it is proposed to replace the elementary cell capacitors with varactors. Results. The obtained field distributions show that the defect partially reflects the incident EM wave channelized in the planar hyperbolic metamaterial. As the defect location angle changes, the wave reflection angle also changes. To make a defect unit cell, it will only suffice to change its capacity by 20% from the original, which is quite feasible in modern varactors. Conclusion. The performed studies have shown that the considered planar hyperbolic metamaterial with a structural defect is good for creating tunable electromagnetic wave splitters.

3-10

Authors: S.V. Nedukh

Subject and purpose. In this paper, a technique of determining the elements of the high-frequency susceptibility tensor for a magnetic nanostructure under the conditions of simultaneous applying of external DC and high-frequency AC magnetic fields is proposed. Methods and methodology. During the research, a numerical solution of the Landau–Lifshitz–Hilbert equations was used with help of the mumax3 micromagnetic simulation package. The advantage of this package is the use of discrete computer video card resources to speed up the solution of equations. Results. As an example, the form of the frequency dispersion of the components of the magnetic susceptibility tensor under conditions of resonant excitation of the magnetization precession for a single nano-sized permalloy disk 500 and 3000 nm in diameter using the micromagnetic simulation package was obtained. Conclusions. The demonstrated approach makes possible to use the results of micromagnetic modeling for further tasks of electromagnetic properties modeling of promising planar microwave metamaterials based on nanoscale elements from a magnet.

20-29

Authors: Yu.V. Gorishnya

Subject and Purpose. Tweek-atmospherics (night-time low-frequency atmospherics), along with radio transmission by VLF radio stations, are used to study the lower ionosphere. The predictions of the available analytical theory regarding the polarization of such atmospherics and the previously accumulated experimental material describe the left elliptical polarization as a characteristic feature of the tweek-atmospherics in their tail section. The horizontal geomagnetic field’s component in reflection layer of the lower ionosphere should lead, within the theory framework, to non-reciprocity of the “east–west” and “west – east” propagation of tweeks. The study aim was to determine the polarization of tweek-atmospherics using three-component records and to statistically evaluate the null hypothesis regarding to two polarization parameters of tweek-atmospherics. Methods and Methodology. By the ensemble of experimental tweek-atmospheric records of about 300 examples, that is large enough for statistical processing, the polarization was studied along the atmospherics’ waveforms. Results. For the first (fundamental) harmonic, two characteristics of the polarization of the tweek-atmospherics (the polarization ratio and the phase difference) were calculated and analyzed, depending on the parameter identical to an incidence angle. The difference in the polarization ratio values has found between tweek-atmospherics with near-equatorial paths and atmospherics outside the geomagnetic equator area, where the condition of quasi-longitudinal wave propagation along the geomagnetic field is satisfied. Conclusions. Study has shown that the non-reciprocity of the propagation of tweek-atmospherics in the “east–west” and “west–east” directions regarding the geomagnetic field is observed as statistically significant differences in the phase difference at an incidence angle about 40...60˚ that correspond to an ending of head area of atmospheric waveforms.

35-45

Authors: R.E. Pashchenko, V.K. Ivanov, D.O. Tsyupak, U.V. Levadniy

Subject and purpose. The frequency-temporal analysis signals of Doppler radar are in-process conducted multirotor drone. The wide use multirotor drone the results in the necessity of arrangement their flights and control after their use. The basic structural feature of such drone is a presence of rotors which provide their motion, the number of which can change depending on a construction. Methods and methodology. The method experimental researches of the revolved rotors of drone are offered with the use of Doppler radar. Terms and composition of the instrumentation-informative system, in-use during the leadthrough of experiment are described. Results. It is set as a result of the conducted analysis, that with the increase pulsatance of rotation rotor the period of Doppler signal (DS) diminishes (frequency rises), however fixed frequency DS less than pulsatance of rotation, set from a control of drone stand. Thus, than anymore frequency of rotation, the more difference of these frequencies. The features of structure (forms) DS and their spectrums which are complicated at the increase frequency of rotation rotor and their amount are exposed. The features of DS are investigational at different direction of rotation rotors (in one side or in different) at similar their geometrical location. Influence of direction of rotation is thus rotined on the form of temporal realization of DS and their spectrums. Conclusion. The exposed differences in form Doppler signals can be in future utillized for recognition type of drone, and also at the construction models of Doppler signals reflected from drone.

53-62

Authors: V.A. Zolotarev

Subject and purpose. The article describes a new S-band transmit/receive module (TRM). The purpose of the work is to describe characteristics of the module, as well as the main technical and technological solutions introduced. Methods and methodology. In the design of the TRM, numerical methods for simulation microstrip lines and microwave devices were used, and the verification of the proposed technical and technological solutions was carried out experimentally. The Reduction of the cost of production of TRM, as well as the availability of the components were one of the main criteria for choosing the appropriate solutions. Results. The paper describes results of the developing of a S-band transmit/receive module (TRM) with the output power of 50 W intended for the use in active phased array radars. Described solutions that have allowed to reduce the cost of such module, to simplify its production when reaching the characteristics attractive to consumers. The module is developed by using microwave monolithic integrated circuits (MMICs) which are widespread used in 3G, 4G communication systems. The module components are placed on a common printed circuit board (PCB) with a FR-4 substrate. The receiving path provides 36 dB gain with the noise figure of 1.4 dB in the 2.8-3.2 GHz frequency band. Separate 6-bit attenuators and phase shifter are used to control the amplification and the phase shift. The introduced protection systems allow a safe operation of the module with any loads at the antenna port. Conclusions. This paper presents a new S-band TRM, which is based on MMICs widely are used in communication systems. The using of these electronic components, as well as modern powerful gallium-nitride (GaN) components and inexpensive composite materials as the substrate for the PCB, has made it possible to improve the efficiency and reduce the cost of TRM in comparison with existing analogues. High output power, low noise of the receiver and the high isolation of the receiving and transmitting channels in the proposed TRM make it promising for use in modern active phased array radars.

3-8

Authors: Hе Shi, N.G. Kokodiy, M.V. Kaydash, S.N. Shulga, S.V. Pogorelov

Subject and Purpose. In laser measurements technique, the absorption and scattering of microwave radiation in a wire, which diameter is much smaller than the wavelength, can be very large. The absorption and scattering efficiency factors can reach values of several hundreds. This effect has been investigated under the conditions when a plane wave falls on a wire in free space and the electric vector of the wave is parallel to the wire axis. The effect also appears if the wire is located along the axis of the radiation beam, but in this case the absorption in thin wires is appeared to be less. In thicker wires, it may be large. This paper shows that such an effect exists when a thin wire is located along the axis of the beam propagating in a hollow metallic waveguide. Methods and methodology. An experimental study of the effect of strong interaction of microwave radiation with very thin (d << l) metal wires located along the axis of a hollow metal waveguide was carried out. The transmittance and reflection coefficients of the waveguide section with a wire in the frequency range from 12 to 18 GHz were measured. The absorption and scattering coefficients of the wires are evaluated. The diameters of the wires ranged from 50 to 1000 microns, while their length ranged from 100 to 200 mm. The waveguide cross-section is 8 ´ 16 mm, the wave type is H10. Results. Our experiments have shown that the transmittance values of the section with the fiber are in the range of 80…90 %; the reflectance values are in the range 1…5 %, depending on the fiber length and its diameter. At some frequencies, where resonances are observed, the transmittance reduces down to 10…20 %, and the reflectance increases up to 10…40 %. Conclusions. The results of our study have showed the existence of the effect of strong interaction of microwave radiation with very thin conductive fibers in the waveguide with a longitudinal fiber arrangement. The effect can be used in the development of waveguide elements for measuring equipment: attenuators, absorbing loads, etc.

21-29

Authors: A.P. Nickolaenko, Yu.P. Galuk, M. Hayakawa

Objective and purpose of the work. We model disturbances in amplitude spectra of vertical electric and horizontal magnetic field components of the signals of global electromagnetic (Schumann) resonance by a seismogenic non-uniformity of the middle atmosphere. The point field source is used positioned at S-E Asia, Africa, or S. America. Observer is found at the Moshiri observatory in Japan (44.37 N, 142.24 E.) and the earthquake modifying the middle atmosphere is situated at Taiwan (21.82 N; 120.81 E). Disturbances are computed in amplitude Schumann resonance spectra and their similarity is demonstrated to observational data. Methods and methodology of work. The propagation parameters of extremely low frequency (ELF) radio waves are found by using the full wave solution in form of Riccati equation. The spectral components of fields are found numerically be using the two dimension telegraph equations having the parameters of regular and non-uniform Earth – ionosphere cavity. Results. We obtain numerical estimates for an impact of localized seismogenic non-uniformity on amplitude spectra of electric and magnetic fields in the frequency band of global electromagnetic (Schumann) resonance. Similarity is demonstrated between the model and observational spectra. Conclusion. The model suggested for a seismogenic non-uniformity in the moddle atmosphere allows to successfully interpret the observations ELF data.

45-60

Authors: M.V. Mil’cho

Subject and purpose. Presently, there is a problem of creation of simple in exploitation generators for a sub-millimeter range, especially in his shot-wave part. Electro-vacuum generators of type BWT and klynotron are work out for long wave part of sub-millimeter range. Difficulties at designing are increase with shortening of wave length. The sizes of the slow-wave structures diminish, requirement to the density of current of electronic bunches and to quality of their focusing, increase. The use electro-vacuum multipliers of frequency, can weaken these requirements considerably. The numeral research of the catcher for the electro-vacuum frequency multiplier, is described in this paper for sub millimeter range. The aim of these researches are an estimation of attainable output power of frequency multipliers and search of optimal parameters for their realization in sub-millimeter range of waves. Methods and methodology. For a calculation catcher efficiency, the analysis of three-dimension motion of electronic bunch in set field of the slowing wave system is conducted. For the numeral integration of the electron motion equation, the universal program “KLYNOTRON” is used. This program was worked out by us before for BWT and klynotron research. In this program many parameters of the real task are take into account. For description of spatial distribution longitudinal and transversal constituents of electric-field tension, the exact analytical method of conformal mapping is used. Thus, all spatial harmonics of the field are taken into account at once in analytical expressions and the field singularity is exactly described near-by the ribs of metallic elements. Results. A numeral study of catcher parameter influence is undertaken on the output power of multiplier. On the ranges of waves 0,5 mm and 0,3 mm the regime and possible for realization catcher structural parameters are certain Conclusions. Undertaken a study showed that at existent technological possibilities really to create the multipliers of frequency in the range of waves at 0.3…0.5 mm with output power at order ten millwatt. A necessary condition for creation of such devices is optimization of parameters of buncher of electronic clots in the multiplier of frequency.

67-82

Authors: V.V. Ovsyanikov, D.M. Svinarenko, E.R. Beznosova, L.Z. Tsypko

The subject and purpose of the work. The methods and results of calculations of the electrical characteristics of the wire randomly bent antennas of the microwave range have been investigated with the purpose of significantly expanding their capabilities and increasing the accuracy of the electrical parameters computations. Methods and methodology of work. The methods and methodology of studies of arbitrarily curved wire whip and loop antennas are considered with concentrated arbitrary loads and excitation nodes included at arbitrary points. An approximate calculation of such antennas is performed by the method of an equivalent long line, and rigorous calculation by the integral equation method with respect to the distribution of the complex current on the antenna. Results of the work. The algorithm of step-by-step development of randomly bent wire whip and loop antennas with arbitrary concentrated loads and excitation nodes included at arbitrary points is proposed. A comparative analysis of the possibilities and errors in calculating approximate and rigorous methods for calculating similar antennas is performed. Аn approximate methods are quite useful for preliminary estimation of input parameters of antennas, and also as an initial approximation for the parametric synthesis of a developed antenna or antenna system. If the accuracy of calculating the antenna parameters by an approximate method is insufficient, it is recommended to apply a rigorous method – the integral equation. The singularities of solving integral equations with respect to the distribution of complex current on linear arbitrarily curved thin pin and loop antennas composed of rectilinear segments of conductors with an arbitrary number of concentrated complex loads and excitation nodes are studied. It is shown that the application of Fredholm integral equations of the first kind to the analysis of such antennas with allowance for the Pocklington integral equation makes it possible to expand the variety of variants of their configuration. However, such integral equations, as is well known, do not satisfy the condition for the correctness of the solution. This negative property leads to instability of the solution of the problem for the current by the integral equation method and to a decrease in the accuracy of calculation of the antenna parameters. To eliminate such a defect and to obtain a stable solution of the integral equation, a method is proposed for diagonalizing the matrix of the coefficients of the system of equations. To solve the problem of calculating such antennas, DISTRIBUTION software was proposed, with the help of which a number of calculations of various pin and loop bent antennas with loads were performed. Examples of calculation with the help of this computer program of the direct and inverse matrices of the system of algebraic equations are given and then the determination of the complex distribution of the current and the input resistance of the investigated antennas is given. The conclusion. The type of antennas under investigation is expanded and the accuracy of calculations of their parameters is increased. It was noted that for the first time in the world practice the method of the integral equation for the calculation of such antennas was proposed and published, which outstripped the development time, the methods and computer programs proposed subsequently. The results of the calculations are consistent with the literature data and experimental results. Based on the studies of antennas by the integral equation method, new designs were developed, some of which were introduced into production and operation when installed on space vehicles and other objects