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1.  Analysis of impulse fields reflected from layered medium with losses using artificial neural network
Shyrokorad D. V., Dumin O.M., Dumina O.O., Katrich V.O.
time domain, artificial neural network, impulse fields, layered medium
Vestnik KhNU 883 Pages. 35-40

The problem of determination of thickness a layer of layered medium by impulse irradiation is solved. The impulse fields reflected from the layered medium with electrical characteristics close to the characteristics of human skin are analyzed by artificia


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2.  Experimental study of diffraction of electromagnetic waves on the lattice of elements of the complex profile
Ivanchenko D.D., Maleev M. N.
the difraction electromagnetic waves, chiral grates, frequency-poiarization property
Vestnik KhNU 883 Pages. 54-58

In given paper the diffraction of electromagnetic waves on volume grid is investigated experimentally. The grid consists of rectangular elements. Two planes of two-dimensional periodic rectangular metallic string elements located on both dielectric surfac


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3.  About convergence of the mode expansions onto spherical harmonic in time domain
Kochetov B.A., Butrym A.Yu.
mode basis method, transient field, spherical modes, ring current
Vestnik KhNU 883 Pages. 41-44

The convergence of spherical mode expansions in the time domain to the exact solution is shown on an example of a test problem that has a closed-form solution. Radiation of a ring with transient current in free space is considered. It was shown that there


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4.  Construction of mode basis for open dielectric structures by integral equation method
Legenkiy M.N., Butrym A.Yu.
mode basis method, open waveguide, eigenmode
Vestnik KhNU 883 Pages. 50-53

A new method based on integral equation formulation is proposed for construction of mode basis in open dielectric waveguides. Decomposition of the spectrum in such structures into discrete (surface wave) and continuous (volume wave) part is analyzed. Disp


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5.  FREQUENCY MULTIPLICATION AT IMPUCT IONIZATION IN TRASFER ELECTRON DIODES ON BASIS AlN, InN
E. D. Prokhorov, O.V. Botsula, I. A. Grishchenko
AlN, GaN, InN diodes, frequency transformation factor , drift velocity, harmonics.
Vestnik KhNU 883 Pages. 30-34

Multiplication of frequency at impact ionization in intervalley transfer electron diodes on basis InN, AlN is considered. The current voltage characteristics of intervalley transfer electron diodes have negative conductivity region and strong increasing


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6.  Investigation of different temperature modes of auxilliary cathode work in magnetrons with cold secondary-emission cathode
Avtomonov N.I., Vavriv D.M., Sosnytsky S.V.
Magnetron, cathode, thermionic cathode, thermo emission, temperature
Vestnik KhNU 883 Pages. 73-82

A theoretical investigation of the emission current temperature dependence of the auxiliary cathode in magnetrons with cold secondary-emission cathodes is performed. Different methods of providing a spatial-charge limited emission from the auxiliary catho


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7.  Quantum efficiency spectral chracteristics of resonant cavity photodector taking into account thermal gradient
S.V. Gryshchenko,
Resonant cavity photodetector, refractive index, temperature shift
Vestnik KhNU 883 Pages. 8-11

In paper a theoretical analysis of quantum efficiency of resonance InGaAs/GaAs P-i-n photodetector (RCE PD) is presented. A mathematical model plugs in itself the transfer matrix method, heat conductivity calculation and dependence of index of refraction


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8.  Determination of optimal parameters of a magnetocardiographic hexagonal measuring grid
A.Yu. Kostiev, A.Yu. Butrym, S.N. Shulga
magnetocardiography, gradiometer, current dipole, sensitivity, Hessian
Vestnik KhNU 883 Pages. 25-29

The article considers hexagonal grid of gradiometer sensors of magnetic field. The aim of the study is to determine the optimal parameters of the grid and the gradiometers in order to obtain maximum sensitivity of the measuring system in terms of location


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9.  Longitudinal slot in a rectangular waveguide with dielectric layer parallel to wide walls
A.A.Liakhovskyi
slot, microwaves, waveguide, dielectric, admittance, scattering parameters.
Vestnik KhNU 883 Pages. 59-66

The longitudinal slot is cut in wide wall of rectangular waveguide with three-layer dielectric filling which parallel to wide wall is considered. The excitation problem is solved with modified eigen waves method. As eigen waves of the LM- and LE- modes ar


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10.  ABOUT SPURIOUS RESONANCES IN PROBLEMS OF DIFRACTION WAVES ON WAVEGUIDE DISCONTINUITY
Mizernik V.N., Shmat'ko A.A.
spurious resonances, a branching of the waveguides, mathching uniformity, connection area, system of the linear algebraicequations
Vestnik KhNU 883 Pages. 67-72

In work it is shown, that the problem of existence of spurious resonances in problems of diffraction waveguide waves on various discontinue in waveguides is connected with incorrect representation of matrix elements of system of the linear algebraic equat


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11.  Ballistic electronic transport in continuous-band superlattice under applied electrostatic field
S.I.Petrov, Klymenko M. V., Shulika O. V.
ballistic transport, superlattice, effective potential
Vestnik KhNU 883 Pages. 12-19

We address in this work ballistic transport of electrons in semiconductor continuous-band superlattice under applied electrostatic field. Combined influence of the effective mass periodically varied in space and external electrostatic field on the electro


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12.  Dielectric permittivity profile reconstruction by frequency probing problem for a plane-layered media with regard to dispersion
Batrakov D.O., Simachov O.A.
plane layered media, dispersion, inverse problem, dielectric permittivity
Vestnik KhNU 883 Pages. 45-49

In the present paper the problem of dielectric permittivity profile reconstruction with regard to dispersion is discussed. The nature of dispersion function is assumed to be known and unknown functions are real and imaginary parts of dielectric permittivi


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13.  Microstrip structures with photonic band gap
Fesenko V.I., Sukhoivanov I.A., Shul'ga S.N.
photonics band gap, microstrip, filter
Vestnik KhNU 883 Pages. 20-24

In this paper, it is presented a two-sided one-dimensional photonic bandgap microstrip structure. The structure is obtained by etching a one periodic pattern of circles in the ground plane of a microstrip line and variation of the characteristic impedance


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14.  The accumulation of gas in galactic objects
Sorokin A.A., Sorokin A.F., Zaharova M., Sokolova O.V., Gorobets N.N.
astrophysics, galactic objects, the accumulation of gas
Vestnik KhNU 883 Pages. 3-7

The mechanism of the accumulation of gas in the galactic objects submerged in the large-scale magnetic field is examined. As a consequence of the diamagnetism of the plasma subsystem of object, the stopper geometry of magnetic field with the radial electr


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15.  Compromising emanations: overview and system analysis
N.N. Gorobets, .V. Trivaylo
compromising emanations, near-field-zone, electromagnetic, radiation, time domain
Vestnik KhNU 883 Pages. 83-88

The problem of compromising radiation of spurious signals in the near, intermediate and far zones of observation in time domain are considered. The Compromising emanation system analysis for finding spurious radiation is proposed. The goal of the given approach is to speed the development of technical protection of information. In approximation of the given current distribution it has been suggested a solution considering the influence of the near-field effects upon directional characteristics of spurious signals radiation. The application of the new method allows us to investigate compromising of technical means in time and frequency domain.


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16.  

magnetron, cathode, thermionic cathode, thermo emission, temperature.
Vestnik KhNU 883 Pages. 73-82

A theoretical investigation of the emission current temperature dependence of the auxiliary cathode in magnetrons with cold secondary-emission cathodes is performed. Different methods of providing a spatial-charge limited emission from the auxiliary cathode are studied in order to eliminate the temperature dependence of auxiliary cathode thermionic current. A new design of the auxiliary cathode is proposed, which is supposed to provide a greater stability with respect to the cathode temperature variations as compared to the currently manufactured magnetrons.


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17.  

astrophysics, galactic objects, the accumulation of gas
Vestnik KhNU 883 Pages. 3-7

The mechanism of the accumulation of gas in the galactic objects submerged in the large-scale magnetic field is examined. As a consequence of the diamagnetism of the plasma subsystem of object, the stopper geometry of magnetic field with the radial electric field is formed. In this configuration, effective retention and the accumulation of the plasma, which revolves in the lattice-type fields, occurs. Atoms are tightly connected on the effects of recharge with the ions, which provides their accumulation. The calculated distributions of molecular and atomic hydrogen in our Galaxy, whose the stopper geometry of its magnetic field is well-known, are given. It is shown that this mechanism describes well the basic special features of gas subsystems


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18.  


Vestnik KhNU 883 Pages. 8-11

In paper a theoretical analysis of quantum efficiency of resonance InGaAs/GaAs P-i-n photodetector (RCE PD) is presented. A mathematical model plugs in itself the transfer matrix method, heat conductivity calculation and dependence of index of refraction from a temperature. Distributing of temperature in the structure of RCE PD and quantum efficiency taking into account the gradient of temperature was calculated.


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19.  

ballistic transport, superlattice, effective potential
Vestnik KhNU 883 Pages. 12-19

We address in this work ballistic transport of electrons in semiconductor continuous-band superlattice under applied electrostatic field. Combined influence of the effective mass periodically varied in space and external electro-static field on the electron transport leads to new undiscovered phenomena. We consider transport at the center of the Brillouin zone as well as off-center-zone transport. Results obtained open possibility for control of electron transport in semiconductor superlattices.


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20.  

photonics band gap, microstrip, filter
Vestnik KhNU 883 Pages. 20-24

In this paper, it is presented a two-sided one-dimensional photonic bandgap microstrip structure. The structure is obtained by etching a one periodic pattern of circles in the ground plane of a microstrip line and variation of the characteristic impedance as a function of the length of the microstrip line. The calculated scattering parameters of the proposed filter are presented.


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21.  
magnetocardiography, gradiometer, current dipole, sensitivity, Hessian

Vestnik KhNU 883 Pages. 25-29

The article considers hexagonal grid of gradiometer sensors of magnetic field. The aim of the study is to determine the optimal parameters of the grid and the gradiometers in order to obtain maximum sensitivity of the measuring system in terms of location of a pointwise dipole source of magnetic field in some spatial region. These parameters are the distance between adjacent gradiometers in the grid (base of the grid) and the distance between two coils within gradiometer (base of the gradiometer). The obtained results allowed us to formulate some recommendations regarding design of such magnetocardiographic measuring system.


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22.  

AlN, GaN, InN diodes, frequency transformation factor , drift velocity, harmonics.
Vestnik KhNU 883 Pages. 30-34

Multiplication of frequency at impact ionization in intervalley transfer electron diodes on basis InN, AlN is considered. The current voltage characteristics of intervalley transfer electron diodes have negative conductivity region and strong increasing current regions due to impact ionization that is nonlinearity and lead to transparent frequency. If impact ionization takes place, frequency transformation factor increases and reaches, for example, 40 % for second harmonic have being showed. The frequency transformation factor increases for second and third harmonic if first harmonic voltage amplitude is several threshold voltage if compare with frequency transformation factor for all nitride compounds.


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23.  

time domain, artificial neural network, impulse fields, layered medium
Vestnik KhNU 883 Pages. 35-40

The problem of determination of thickness a layer of layered medium by impulse irradiation is solved. The impulse fields reflected from the layered medium with electrical characteristics close to the characteristics of human skin are analyzed by artificial neural network in time domain directly. The normal incidence of plane wave with Gaussian time form is considered. The reflected electromagnetic field is calculated by FDTD method. Initial data for the neural network analysis are the values of amplitude of electrical component of reflected field. As an example, the network is trained to determine the thickness of one of the layers of the medium. The stability of the determination in presence of interferences, experimental errors and instabilities of medium parameters is investigated.


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24.  

mode basis method, transient field, spherical modes, ring current.
Vestnik KhNU 883 Pages. 41-44

The convergence of spherical mode expansions in the time domain to the exact solution is shown on an example of a test problem that has a closed-form solution. Radiation of a ring with transient current in free space is considered. It was shown that there exist only a finite number of propagating modes for any frequency at any given radius of a circumventing spherical surface. Thus within the framework of mode basis method in spherical coordinate system a finite number of main modes is sufficient to describe radiation of a transient sources located within a sphere of some given radius.


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25.  

layered media, dispersion, inverse problem, dielectric permittivity.
Vestnik KhNU 883 Pages. 45-49

In the present paper the problem of dielectric permittivity profile reconstruction with regard to dispersion is discussed. The nature of the dispersion function is assumed to be known and unknown functions are real and imaginary parts of dielectric permittivity. Frequency is used as an informative parameter. It is assumed that the layered medium is laying on a substrate with known dielectric permittivity and permeability. The iterative method reducing the problem of reconstruction to the functional minimization problem is used. Within the scope of this method the inverse problem for of dielectric permittivity profile with a conducting medium dispersion is solved. The algorithm and numerical results are given.


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26.  


Vestnik KhNU 883 Pages. 50-53

A new method based on integral equation formulation is proposed for construction of mode basis in open dielectric waveguides. Decomposition of the spectrum in such structures into discrete (surface wave) and continuous (volume wave) part is analyzed. Dispersion equation for modes of the discrete spectrum and analytical formulae for calculation of mode functions of the discrete and continuous spectrum have been found. The examples of the discrete and continuous spectrum mode function are shown. Orthogonality of the mode function is demonstrated analytically. The expression for norm function has been found in a closed form.


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27.  

diffraction electromagnetic waves, chiral structure, polarization properties on frequency
Vestnik KhNU 883 Pages. 54-58

In given paper the diffraction of electromagnetic waves on volume grid is investigated experimentally. The grid consists of rectangular elements. Two planes of two-dimensional periodic rectangular metallic string elements located on both dielectric surfaces and connected by cylindrical conductors. The measurements of dependence of grid transmission index on frequency and polarization are carried out. The measurements were made in frequency range 26-38,8 GHz. The grid was irradiated by quasi-plane wave with incident on the normal to the surface of the grid.


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28.  

slot, microwaves, waveguide, dielectric, admittance, scattering parameters
Vestnik KhNU 883 Pages. 59-66

The problem of a longitudinal slot radiation is cut in wide wall of rectangular waveguide with three-layer dielectric filling which parallel to wide wall of a waveguide was solved. The excitation problem is solved with modified eigen waves method. As eigen waves of the LM- and LE- modes are chosen. The field in the source region includes the potential functions as well. The scattering parameters and resonance properties of slot are investigated. The scattering parameters calculated are in a good agreement with experimental data.


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29.  

spurious resonance, a branching of the waveguides, matching uniformity, connection area, system of the linear algebraic equations.
Vestnik KhNU 883 Pages. 67-72

In work it is shown, that the problem of existence of spurious resonances in problems of diffraction waveguide waves on various discontinue in waveguides is connected with incorrect representation of matrix elements of system of the linear algebraic equations (SLAE) which lead to features at their numerical decision. On an example of a problem of diffraction waveguide waves on the -branching of rectangular wave guides it is shown, that spurious resonances correspond to resonances of area of connection of waveguides. This computing mistake can be rather simply corrected due to correct representation of matrix elements SLAE which has no features. Results of calculations have shown efficiency of such approach for the decision of problems on own oscillations and problems of diffraction on the -branching of hollow wave guides, and tees with dielectric and ferrite resonators in the field of connection of waveguides.


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30.  Compromising emanations: overview and system analysis
N.N. Gorobets, A.V. Trivaylo
compromising emanations, near-field-zone, electromagnetic, radiation, time domain
Vestnik KhNU 883 Pages. 83-88

The problem of compromising radiation of spurious signals in the near, intermediate and far zones of observation in time domain are considered. The Compromising emanation system analysis for finding spurious radiation is proposed. The goal of the given approach is to speed the development of technical protection of information. In approximation of the given current distribution it has been suggested a solution considering the influence of the near-field effects upon directional characteristics of spurious signals radiation. The application of the new method allows us to investigate compromising of technical means in time and frequency domain.


Download >>

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