Y.K. Sirenko
A. Usikov Institute of Radio Physics and Electronics, National Academy of Sciences of Ukraine
12, Academician Proskura St., Kharkov 61085, Ukraine
Exact 'Absorbing' Conditions in Outer Initial Boundary-Value
Problems of Electrodynamics of Nonsinusoidal Waves.
Part 1. Fundamental Theoretical Statements.
A series of papers under the common title is devoted to the solution of the central problem
of computational radio physics, namely, the problem of correct and efficient truncation
of a computational domain in finite-difference methods used for algorithmization of the outer initial
boundary-value problems in electrodynamics of nonsinusoidal waves. In the first paper,
the theoretical results providing a basis for further derivations are presented, as well as
the advancements and the current problems of this field of research are considered.
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V.M. Onufriyenko and T.I. Slyusarova
Zaporozhye National Technical University,
64, Zhukovskogo St., Zaporozhye, 69063, Ukraine
An Integro-Differential Model for the Interaction of a Monochromatic Wave with a Circular Cylinder
Results of integro-differential modeling of the internal field diffracted by a fairly thin cylinder
(quasistationary case) are presented. The study is based on fractal representation of the
cylinder's surface structure. The model suggested employs -characteristics to describe surfaces
with an arbitrary fractal dimensionality. The results obtained for 0-characteristics are consistent with the classical data.
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N.P. Yegorova
V. Karazin National University of Kharkov,
4, Svoboda Sq., Kharkov, 61077, Ukraine
Analytical Solution of the Helmholtz Equation for Wave Beams in Free Space
A new approach is suggested to analyzing the Helmholtz equation.
An analytical solution has been obtained in which the dependence of amplitude upon the
longitudinal coordinate is described by the Weber function. The results, of this paper may
be useful in the analysis of fields in open oscillatory systems, antennas, transmission lines
and other devices of the shorter wavelength part of the millimeter waveband.
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A.I. Vyazmitinova
A. Usikov Institute of Radio Physics and Electronics, National Academy of Sciences of Ukraine
12, Academician Proskura St., Kharkov 61085, Ukraine
Electrodynamic Analysis of the Laminated Luneberg Lens
The interaction of E-polarized waves with the axially symmetric structure has been numerically studied
in the case that the structure permittivity is described by the step function approximating the permittivity
of the Luneberg lens. It has been found that the laminated lens, as well as the regular Luneberg lens,
is a broadband device. The effects caused by the excitation of 'azimuth' resonances in a layer dielectric structure
have also been examined.
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G.P. Pochanin
A. Usikov Institute of Radio Physics and Electronics, National Academy of Sciences of Ukraine
12, Academician Proskura St., Kharkov 61085, Ukraine
Radiation of Various Duration Signals by a Tunable
Large-Current Antenna System
Results are presented of experimental investigations aimed at the creation of a tunable antenna
system permitting to radiate pulsed signals of various durations from the range of 3 to 5 ns.
The system is a four-element radiator whose elements are the Harmuth large-current antennas.
Main relationships defining the possibility to retune the duration of radiated signal, principle of operation
of the system, and results of measuring of spatial and time characteristic of the radiation are discussed in the article.
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A.P. Yevdokimov and V.V. Kryzhanovsky
A. Usikov Institute of Radio Physics and Electronics, National Academy of Sciences of Ukraine
12, Academician Proskura St., Kharkov 61085, Ukraine
Optimization of the Radiating System “Dielectric Waveguide-Grating”
for an Automobile Radar Scanning Antenna
A radiating system consisting of a linear dielectric waveguide and a comb-type diffraction grating is considered.
The prerequisite to the formation of the system's pattern in a vertical plane with a horizontally positioned dielectric
waveguide axis has been explored. The effect of the comb width on the shape of the pattern has been analyzed.
The optimal illumination angles of the cylindrical lens or parabaloid with radiation being focused in a vertical plane
have been determined. The formation of the pattern by joint-butting two parallel-positioned gratings, which, in the case,
have different values of periods, has been studied. A criterion has been specified for the continuous scanning mode
in the system composed of a linear dielectric waveguide and relatively narrow teeth arranged on the lateral surface
of the barrel in such a way that it can rotate about its axis. Practical recommendations are proposed to design the
scanning antennas offering step-by-step or continuous scanning modes.
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V.L. Pazynin
A. Usikov Institute for Radiophisics and Electronics Natonal Academy of Sciences of Ukraine
12, Academiccian Proskura St., Kharkov, 61085, Ukraine
Self-Shadowing Influence on the Reflection from a Random Stepped Surface
The beam reflection from a stepped surface having a stochastic size of steps has been scrutinized
using a geometrical optics approach. The coefficient that accounts for the effect of self-shadowing this
type of surface is elaborated through auxiliary functions, each of them corresponding to the solution
of integro-differential equation. In this paper the exact solution of these equations is constructed
for the exponential function of the step height distribution density. In contrast to the earlier investigations
this solution is validated for the finite distances between a receiver and a source and a random surface.
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I.M. Mytsenko and S.I. Khomenko
A. Usikov Institute of Radio Physics and Electronics, National Academy of Sciences of Ukraine
12, Academician Proskura St., Kharkov 61085, Ukraine
Peculiarities of UHF- and VHF-band Over-the-Horizon Location of Above-Water Objects in the Presence of Inversion Layers
An influence of sea surface reflections on the shape of the distance-dependent wave attenuation factor and,
consequently, upon the possibility of over-the-horizon location of above-water objects at particular distances
given inversion layers is shown.
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A.A. Malyshev
Kharkov Military University
Measurements of Low-Flying Target Altitudes in Standard Three-Dimensional Surveillance VHF-Band Radars
A series of practicable ways to improve the measurement accuracy of low-flying target angles of elevation
in 3-dimensional standard surveillance VHF-band radars are analyzed. Methods for estimating the true altitude
of air-borne objects with available and unavailable a priori information on the earth surface pattern are considered.
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M.M. Bykov, S.V. Tyurin, A.V. Glinyanyi, and V.A. Romanyuk
Kharkov National University of Radio Engineering and Electronics,
14, Lenin Ave, Kharkov, 61166, Ukraine
Hardly Noticeable Target Location and Identification by Lidar Methods
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O.A. Ovchinkin and V.G.Sugak
A. Usikov Institute of Radio Physics and Electronics, National Academy of Sciences of Ukraine
12, Academician Proskura St., Kharkov 61085, Ukraine
The Influence of Soil Electric Properties upon the Ground-Penetrating
Radar (GPR) Signal Characteristics
A refined model relating to the electric constants of typical soils is employed to examine their influence
on the characteristics of the GPR signal transmitted through a layer of different depth in subsurface sensing.
The dispersion features of the soil electric properties influencing the sensing signal resolution are evaluated.
The requirements for the spectrum width of a probing signal and its position on the axis of frequencies
as a function of a required sensing depth and soil moisture are specified.
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A. M. Gokov and O. F. Tyrnov
V. Karazin National University of Kharkov,
4, Svoboda Sq., Kharkov, 61077, Ukraine
Low Frequency Whistlers Generated in the Lower Ionosphere
During Strong Thunderstorms
Methods of determination whistler frequencies generated by the infrasound in E- and F- regions
of the ionosphere near the strong thunderstorm epicentre in the Earth atmosphere are proposed. Experimentally,
using methods of the vertical Doppler sounding and partial reflections, it has been confirmed the principle that the during
a strong thunderstorm, near the epicentre, generating of infrasonic waves of f1 0.4-0.8 Hz which spread up to the ionospheric
F-region heights is possible. On the basis of both the infrasonic waves transformed in the ionosphere into the low frequency
whistlers and the dispersion relations, the whistler frequencies were found to be f3 7-29 kHz, which agrees closely with
the theoretical calculations.
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A.M. Gokov and O.F. Tyrnov
V. Karazin National University of Kharkov,
4, Svoboda Sq., Kharkov, 61077, Ukraine
Experimental Investigation of Middle Latitude D-region Ionosphere Responding to Events Related to Proton Precipitations
Using a partial reflection technique, there were experimentally investigated changes in the electron density, N,
in the ionospheric D-region at the time of solar proton events, spe. Increasing by more than 50-100%
in the electron density in the lower D-region of the ionosphere (~70-80 km) was observed during several tens of minutes.
Estimations of changes in the ionization rate were made. On the basis of the experimental data on electron density
changes over the proton precipitation periods, corresponding flows were estimated,
being ~10,6-107m-2sec-1.
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A.M. Gokov, S.I.Martynenko, V.T. Rozumenko, and O.F. Tyrnov
V. Karazin National University of Kharkov,
4, Svoboda Sq., Kharkov, 61077, Ukraine
Remote Earthquake-Induced Large-Scale Ionospheric Disturbances
and Strong Mesospheric Electric Fields
The results of MF radar remote sensing of plasma disturbances at mesospheric heights caused
by severe distant earthquakes are presented. The mechanism underlying the similar effects
of these disturbances is closely associated with the large-scale electric-potential redistribution
owing to an increase in the atmospheric conductivity over a seismic region is described.
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O.V. Gurin, V.A. Maslov, V.A. Svich, A.N. Topkov, and Ye.V. Fursova
V. Karazin Kharkov National University,
4, Svoboda Sq., Kharkov, 61077, Ukraine
A Resonator for Selection and Shaping of the Fourier Mode
with a Uniform Field Amplitude Profile
A description is given of the procedure to select and generate the mode in a generalized confocal resonator.
This mode is featured by the close-to-uniform field amplitude distribution on one of the mirrors.
The characteristics of the lowest-order even-symmetric modes (in terms of losses) were numerically analyzed,
thereby enabling one to find the optimal configurations of the resonator and amplitude-stepped mirror profile serving
to shape these beams.
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M.I. Dzyubenko, S.N. Kolpakov, V.P. Pelipenko, and V.V. Shevchenko
A. Usikov Institute of Radio Physics and Electronics, National Academy of Sciences of Ukraine
12, Academician Proskura St., Kharkov 61085, Ukraine
Research of the Features of the Second Harmonic Generation by Pulse-Periodic Flashlamp-Pumped Dye Lasers
The influence of parameters of laser radiation and the focusing conditions on the efficiency of second harmonic
generation by flashlamp-pumped dye lasers has been investigated experimentally. Necessary conditions
have been optimized for a gradual tuning of the radiation wavelength in a spectral range limited to a spectral band of dye.
A tunable pulse-periodic dye laser has been developed that oscillates in UV-range of 280 to 300 nm.
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