Telecommunications and Radio Engineering, 59(5&6)

Yu. 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 the Electrodynamics of Nonsinusoidal Waves. Part 5: Plausible Extensions and Unresolved Problems

The closing paper of this series is devoted to the analysis of possible extensions of the results obtained. The problems are considered, whose solutions allow to avoid a nonrational expansion of the computational domain when using long-duration primary signals, large and distant sources, as well as in the problems dealing with chains of inhomogeneities with long regular waveguides connecting them.

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A.I. Vyazmitinova, A.O. Perov, and 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 Modeling of Transient Processes in Two-Dimensional Compact Open Resonance Structures

The paper deals with the problem of finding a correct and efficient way to restrict the computational window in the finite difference time domain (FDTD) method applied to the analysis of transient waves in infinite two-dimensional domains containing compact inhomogeneities. The developed approach is based on the formulation of exact absorbing boundary conditions on the grid in the Cartesian coordinates and its incorporation to the computational scheme.

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I.N. Shevchenko and V.G. Krizhanovsky^*
Slavyansk State Pedagogical University
^*Donetsk National University
Technique of the Quick Summation of Forces of Far Interaction between the Particles in N-Body Problem

We report on efficient calculation method for forces of interaction in N-body problem, which allows for time ~O(Nlog(N)) produce the analysis of behavior of such ensembles of particles, for which use of direct summation method requires unbelievably big calculation time. In contrast with other methods of the similar purpose it possesses the advantages, which are important at modeling of the collective processes in semiconductor device by method of the particles.

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N.V. Sidorchuk, V.V. Yachin, and S.L. Prosvirnin
Radio-Astronomical Institute, National Academy of Sciences of Ukraine
4, Krasnoznamyennaya St., Kharkov, 61002, Ukraine
Low-Frequency Approximation for the Problem of Electromagnetic Wave Propagation in a Doubly- Periodic Magnetodielectric Layer

The scattering problem is solved for a plane electromagnetic wave incident obliquely upon a doubly-periodic magnetodielectric layer bounded by two homogeneous media. The problem of determination of layer eigenmodes is investigated in the low-frequency range. The Galerkin technique is used to obtain the boundary problem for the set of linear differential equations with constant coefficients and, consequently, to determine amplitudes of scattered waves.

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V.G. Gutnik, G.P. Kulemin^*, L.I. Sharapov and N.V. Gorbach
Radioastronomical Institurte, National Academy of Sciences of Ukraine
4, Krasnosnamennaya St., Kharkov 61002, Ukraine
^*A. Usikov Institute of Radio Physics and Electronics National Academy of Sciences of Ukraine
12. Academician Proscura St.. Kharkov 61085. Ukraine
Power Spectra of Radar Echoes from a Perturbed Sea Surface at Small Grazing Angles

Power spectra of the radar signals scattered by the sea at 1 to 150GHz are analyzed. Relations between the spectrum parameters and the radar operating frequency, wind speed and sea wave height are discussed. The power spectra measured at the frequency of 140GHz are presented. As has been found, millimeter wave power spectra produced by breaking sea waves are bimodal. .Relations between the second mode parameters and sea roughness are analyzed, leading to the conclusion that the second mode is produced by scattering from the water-drop fraction (splashes) which is formed as a result of sea wave breaking.

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V.G.Gutnik, N.V.Gorbach, V.N. Gorobetz^*, and L.I.Sharapov
Radioastronomical Institurte, National Academy of Sciences of Ukraine
4, Krasnosnamennaya St., Kharkov 61002, Ukraine
^*A. Usikov Institute of Radio Physics and Electronics National Academy of Sciences of Ukraine
12. Academician Proscura St.. Kharkov 61085. Ukraine
Fluctuation Statistics of Short-Wave Millimeter Waveband Radio Signals Propagating Above Sea Surface

The results from experimental studies into the amplitude and arrival angle fluctuations of the short-wave millimeter radio signals propagating above sea surface are presented. The peculiar statistical characteristics of these fluctuations are considered. The model explaining the observed peculiarities is suggested. It is concluded that at the short sea distances and small grazing angles the quasi-mirror reflections may occur even from heavily rough surface.

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V.A.Kortunov, V.N.Gorobets, F.V.Kivva, V.A.Kabanov, and I.S.Turgenev
A. Usikov Institute of Radio Physics and Electronics, National Academy of Sciences of Ukraine
12, Academician Proskura St., Kharkov 61085, Ukraine
Study Into Altitude and Frequency Dependencies of Centimeter and Millimeter Radio Wave Signals Propagating Above Sea Surface

The radio signals of centimeter and millimeter wavebands have been measured. The altitude profiles of the signal levels have been found to significantly vary depending on the antenna elevation above the sea level. For this reason the altitude dependencies have been studied using the differential characteristics.

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V.F.Zyukin, A.A.Gryzo and V.M.Andriishin
Technical University of Defense, Kharkov
The Surveillance Radar Potential for Moving Target Indication in the Presence of Inhomogeneous Passive Counter Measures

The present work analyses the autocorrelation function type of the passive jamming interperiodical fluctuations for the case of random variations in their power during the process of regular azimuth survey of the ground-based radar. Approaches aree treated to the synthesis of devices for the interperiodical coherent signal processing under conditions of the a priori parametric ambiguity relative to noise background statistical characteristics. Variants of calculations of the moving targets selection devices quality indices in the considered situations are outlined, some efficiency estimates are given.

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V.N. Oleynikov and B.L. Kashcheyev
Kharkov National University of Radio Engineering and Electronics,
14, Lenin Ave, Kharkov, 61166, Ukraine
Radar Investigations into the Initial Radius of a Meteor Trail

A description and the essential technical features of the equipment for investigating the physical parameters of a meteor trail and the atmosphere are given. The performance of an experiment, processing and interpretation of the results from estimation of the parameters of the meteor trail's initial radius model are discussed.

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O.I. Kharchenko and P.Yu. Sedyshev
Kharkov Military University
The Recursive Methods of Data Processing in Small-Base-Width-Angle-Range-Difference-Measurement Passive Radars

The recursive methods of information procession in small-base-width-angle-range-difference-measurements complexes passive radars (SBMR) are considered. The Kalman filtration algorithm is derived using the strategy of program review of space and transformation of error matrix in curvilinear coordinate system of SBMR.

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S.I Martynenko
V. Karazin National University of Kharkov,
4, Svoboda Sq., Kharkov, 61077, Ukraine
Effect of Powerful Electric Fields in the Mesosphere on Partially Reflected Radio Waves

Studied in the paper is the effect of the ionospheric plasma disturbances produced by powerful electric fields in the mesosphere on partially reflected radio waves (the model of a mesospheric current source is considered). As has been shown, the differential absorption, differential phase and cross-correlation factor of intensities of the partially reflected signals are affected most by disturbances in the effective collision frequency of electrons. The nonlinear distortions of parameters of the partially reflected signals are described, which appear when the lower ionosphere is sounded with high power radio waves from pulsed-mode facilities. The feasibility of employing modified versions of the partial reflections technique for diagnosis of the disturbing mesospheric field is discussed.

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A.M. Gokov
V. Karazin National University of Kharkov,
4, Svoboda Sq., Kharkov, 61077, Ukraine
On the Accuracy Increase of Determining the Lower Ionosphere Parameters Using Amplitude Measurements of Partially Reflected Signals

Based on the experimental data and model calculations it is shown that the difference of experimental height dependences of the ratio of average (during the measurements of ~ 10 min) guadrates of amplitudes of the partially reflected signals of the extraordinary ("x") and ordinary ("o") polarizations a(z, t) from the theoretical ones at the heights of z> 80 km and z< 70 km (which is frequently observed in the experiments and results to additional, frequently essential, errors in determination of the lower ionosphere parameters) is possible becose of simultaneous influence of the following factors: radio noise, the incomplete separation of the "o" and "x" components by receiving equipment and their transformation in the magnetoactive ionosphere, due to difference in their impulse volumes of the "o" and "x" components in space, their differential absorption in the scattering volume, and also due to the essential nonmonotonous of the height electron density and electron-neutral molecule collision frequency profiles (the presence of sharp layers and valleys).

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Yu.V. Gorishnya
A. Usikov Institute of Radio Physics and Electronics, National Academy of Sciences of Ukraine
12, Academician Proskura St., Kharkov 61085, Ukraine
Modeling of Salinity Effect on Wet Soil Remote Sensing Characteristics in L- and P-Bands

The results of numerical simulations of salinity effect on wet soil remote sensing characteristics in L- (20 cm) and P- (70 cm) bands are presented. It is shown that the uncertain detection of saline soils by L-band remote sensing may be caused by the existence of vertical soil moisture profile. Simulation results are given for the errors introduced by soil salinity in different geographical areas into the soil moisture determination using radar remote sensing in L- and P-bands.

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