V.V. Glamazdin, Ê.À. Lukin, and V.N. Skresanov
A. Usikov Institute of Radio Physics and Electronics,
National Academy of Sciences of Ukraine
12, Academician Proskura St., Kharkov 61085, Ukraine
Improvement of Basic Synthetic-Antenna Pattern Characteristics by Comparison Method
The new method of compression in azimuth applied at signals processing from the digital synthetic-antenna radars is considered. The method is based on the nonlinear logical procedure of comparison of two synthetic-antenna patterns calculated from one and the same trajectory signal data array by weighing with the help of appropriate antenna windows. Depending upon the result of comparison the comparison antenna pattern is formed. It is demonstrated that application of comparison antenna pattern is increasing the azimuth resolution, reducing side lobes level and broadening the dynamic bandwidth of target detection in comparison with the regular signal processing using antenna windows, which are optimal in compliance with the Dolf-Chebyshev criterion.
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S.V. Mizrakhy
A. Usikov Institute of Radio Physics and Electronics,
National Academy of Sciences of Ukraine
12, Academician Proskura St., Kharkov 61085, Ukraine
Computational CORDIC Algorithm for Electromagnetic Scattering Problem
The CORDIC algorithm potentialities for numerical solution of some electromagnetic scattering problem is considered. The algorithm allows strictly and fast computing a wide range of trigonometric functions as well as vector rotation for the given angle by shift-add operation. The computation results of Radar Cross Section (RCS) patterns for rectangular cylinder obtained by Geometric Theory of Diffraction using CORDIC are presented.
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A.F. Rusanov and V.M. Yakovenko
A. Usikov Institute of Radio Physics and Electronics,
National Academy of Sciences of Ukraine
12, Academician Proskura Str., Kharkov 61085, Ukraine
Instabilities of Space Charge Waves as a Result of Interaction of an Electron Beam with Layered Semiconductor Cylinder-Shaped Structures
Oscillation processes in cylindrical systems, such as electron beam/layered medium/dielectric (metal), have been studied theoretically on basis of the electrostatic approximation. Dispersion equations for various geometrical configurations of beam-plasma systems have been obtained. On basis of the carried analysis of the dispersion equations it has been shown that at the interaction of a non-relativistic electron beam with solid semiconductor structures which consist of semiconductor layers with different values of the permittivity, instabilities of space charge waves can arise over a wide frequency region.
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T.V. Bagmut, S.V. Nedukh, and M.K. Khodzinsky
A. Usikov Institute of Radio Physics and Electronics,
National Academy of Sciences of Ukraine
12, Academician Proskura St., Kharkov 61085, Ukraine
Magnetoresonance and Magnetoimpedance Properties of Nanocomposites with Spin-Dependent Tunnel Magnetoresistance
Effect of giant magnetoimpedance (GMI), tunnel magnetoresistance (TMR) for magnetic structures (CoFeZr)xSiO1-x -composite (x%=34, 40, 43, 47),
Cox (TiO2) 1-x in the millimeter wavelength range have been studied. An EPR (electron paramagnetic resonance) method has been used to record
the ferromagnetic resonance lines at 300K on frequencies of 38 to 45GHz. The magnetic field-dependent resonant frequencies have been found and analyzed.
Based upon the data obtained the concentration dependencies of saturation magnetization Ms of a substance are calculated for the case where an external static magnetic field is applied in a sample plance. The concentration dependencies of absorption lines have been examined.
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L.F. Kupchenko, G.V. Rybalka, and O.V. Yefimova
Kharkov Military University
6 Svobody Sqr., Kharkiv, 61077, Ukraine
Light Diffraction on Two Ultrasonic Waves Having Different Frequencies
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A.V. Kats, A.Yu. Nikitin, M.L. Nesterov, and Yu.V. Bludov
A. Usikov Institute of Radio Physics and Electronics,
National Academy of Sciences of Ukraine
12, Academician Proskura Str., Kharkiv 61085, Ukraine
Resonance Optical Transmission through Periodically Modulated Metal Films
The sophistical treatment has performed of light tunneling through a metal film, thickness of which exceeds significantly the skin-depth and with a weak modulation of parameters (dielectric permittivity, surface geometry, etc.), taking into account the absorption. Owing to the periodicity, under a defined relation between the angle of incidence, the spatial modulation period, and the wavelength, the process of transforming photons of the incident wave to surface plasmon-polaritons (in terms of the classical principles, that is resonance excitation of symmetrical and antisymmetrical plasmon-polariton modes) takes place, which leads to the essential change in reflectivity and transmission. The cases of incline and normal incidence which correspond to the resonances of different multiplicities (single, double, and fourfold) are investigated. It is found that even for a weak modulation the effect of practically total light transmission occurs (under conditions of practically total opaqueness of an unmodulated film). The systematic use of small parameters has allowed us to present the results in a convenient analytical form. Optimal combinations of parameters (film thickness, modulation depth, etc.) which correspond to maximal transmission have been found. The results are of essential interest in dealing with the problems of optical information technology, in particular, for nano-chip design.
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V.P. Radionov
A. Usikov Institute of Radio Physics and Electronics,
National Academy of Sciences of Ukraine
12, Academician Proskura St., Kharkov 61085, Ukraine
Submillimeter Laser with Continuous Frequency Adjustment within the Limits of Laser Spectrum Line
Submillimeter-wave band laser which is tunable to the predetermined frequency over the spectral line width of an active lasant, is investigated. Adjustment and frequency measurement are performed by means of the micrometric mirror-tuning mechanism calibrated in terms of frequency.
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E.N. Belov, V.K. Ivanov, E.V. Krivenko, V.I. Lutsenko, V.L. Prudky, G.I. Khlopov, 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
Use of Dielectrometry for Evaluation of Component Composition of Gas Mixtures
Dielectric characteristics of gaseous-air mixtures at various pressures are investigated. Data are obtained on polarizabilities of gas and air. In principle, possibility exists to determine component composition of gas mixtures by dielectric characteristics. The proposed approach can be used for evaluation of moisture content in gas being transported.
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