Yu.M. Penkin and R.I. Klimovich
National Academy of Pharmaceutics of Ukraine
53, Pushkinskaya str., Kharkov, 61002, Ukraine
Radiation Impedances of Bent Dipoles near a Perfectly Conducting Sphere

Radiation impedances of thin bent dipoles located near a spherical scatterer have been derived using the tensorial Green's function of electric type for the space exterior to a perfectly conducting sphere. For this case the currents distribution along the electrically short dipole (of order of half the operating wavelength) was approximated to by a sinusoidal function. Self- and coupling resistances of the bent dipoles have been analyzed numerically for variable geometric parameters of radiating systems containing resonant-size spheres.

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A.V. Strizhachenko, A.A. Zvyagintsev , V.V. Chizhov, and V.V. Andreev
V. Karazin National University of Kharkov,
4, Svoboda Sq., Kharkov, 61077, Ukraine
Cylindrical-Rectangular Waveguide Junction as a Model of Measurement Device

This work stands with the series of the works about an electromagnetic modes in waveguide junctions and expansions. Physics of the resonant phenomena in waveguide junctions with anisotropic filling have been investigated: cylindrical-radial waveguides, rectangular-rectangular waveguides, rectangular-planar waveguides, planar-planar waveguides. The electromagnetic and numerical analysis of resonant phenomena in cylindrical-rectangular waveguide junction with magnetodielectric filling is an object of this work. The semi-opened structures under study are widely used for measurements of isotropic and anisotropic material characteristics without their destruction.

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V.F. Kravchenko and N.D. Sizova
Institute of Radio Engineering and Electronics of the RAS, Moscow
Investigation of Some Heat Conductivity Problems by the R-Function Method

Using the Rvachev functions (R-functions) the computation technique of heat conductance problems and others problems of mathematical physics was developed. Algorithms for determining the temperature fields in the nonstationary heat conductivity problems had been presented in this paper. The error estimates was presented.

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Yu.E. Gordienko and D.R. Yakovlev
Kharkov National University of Radio Engineering and Electronics,
14, Lenin Ave, Kharkov, 61166, Ukraine
Mathematical Aspects of the Field-Effect Method for Spectroscopy of Localizated States in Disordered Semiconductors

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V.V. Lukin*, N.N. Ponomarenko*, S.K. Abramov*, AA. Zelensky*, K.O. Egiazarian**, J.T. Astola**
*National Aerospace University (Kharkov Aviation Institute),
17, Chkalov St., Kharkov, 61070, Ukraine
** Institute of Signal Processing,
Tampere University of Technology, Tampere, Finland
Automatic Robust Procedure for Radar Image Preliminary Analysis and Filtering

Quite typical is a situation when it is desirable to process some radar images for which their origin and/or imaging system parameters (operation mode) are unknown and, thus, a priori information about noise characteristics is limited. Then, evaluating these characteristics, for example, estimating multiplicative noise variance is a complicated and time consuming task that commonly requires high skill of the user. To perform both tasks efficiently an automatic robust procedure for SAR and SLAR image preliminary analysis and filtering is proposed and considered. The basic stages of this procedure are the following: a) blind evaluation of multiplicative noise relative variance for the original radar image, b) its pre-processing using the local statistic Lee filter, c) blind evaluation of the residual noise relative variance for the obtained pre-processed image, d) post-filtering. The proposed procedure provides appropriately accurate estimations of noise characteristics. The influence of variance estimation errors on filter performance is analyzed. The effectiveness of the analysis/filtering procedure is confirmed quantitatively for simulated images and demonstrated for real life radar images.

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V.F. Kravchenko and M.V. Golubin
Spectral Properties of New Weighting Functions in Digital Signal Processing

Using the theory of atomic functions (fupn(x)) the new weighting functions (windows) had been developed. Results of numerical experiments and their comparison with classical windows are presented. Effectiveness and reliability of new windows in spectral signal processing was shown.

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V.O. Kovalenko
A. Usikov Institute of Radio Physics and Electronics, National Academy of Sciences of Ukraine
12, Academician Proskura St., Kharkov 61085, Ukraine
Sliding Neighborhood Filters for Ground Penetrating Radar Image Processing

The directions for application of sliding neighborhood filters for processing images obtained at subsurface video pulse sounding have been described in this paper. The filters for the image focusing of local objects and extraction of information about stratified soil structure have been fabricated. The empirical recommendations for using these filters in real applications have been suggested.

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A.B. Zakalyukin, V.D. Yeryomka, A.A. Kurayev, T.L. Popkova, and A.K. Sinitsyn
A. Usikov Institute of Radio Physics and Electronics, National Academy of Sciences of Ukraine
12, Academician Proskura St., Kharkov 61085, Ukraine
O-Type Relativist Corrugated-Waveguide Oscillators

An efficiency of the relativist Cerenkov effect oscillators has been examined by means of the general excitation equations for longitudinally-irregular waveguides. Based on the partial optimization of the profile of the relativist BWO slow-wave structure it has been shown that 40%- and 60%-efficiencies can be attained both in this particular structure and in reflex-klystron oscillators respectively. In both cases an essential role is played by the forward-to-backward wave conversion and vice versa in regular and irregular corrugated waveguides.

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M.I. Dzyubenko, I.G. Naumenko, 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
Second-Order Harmonic Generation in Flashlamp-Pumped Dye Lasers

The second-order harmonic generation in flashlamp-pumped dye lasers is investigated. The efficiency of second-order harmonic generation is analyzed in dependence on the generation bandwidth and divergence of the fundamental frequency. Adjustable laser emission has been produced in two regions of the UV spectral band.

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Yu. E. Kamenev, V. K. Kiselyov, and A. A. Filimonova
A. Usikov Institute of Radio Physics and Electronics, National Academy of Sciences of Ukraine
12, Academician Proskura St., Kharkov 61085, Ukraine
10 THz Laser Source of Radiation

A 10 THz laser source of continuous radiation with the output power of ~ 2 mW has been described. The working substance is water vapor excited by the high-frequency discharge (13.5 MHz). The length of an active zone is 1 m; the internal diameter of a discharging tube is 32 mm.

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Yu. E. Kamenev
A. Usikov Institute of Radio Physics and Electronics, National Academy of Sciences of Ukraine
12, Academician Proskura St., Kharkov 61085, Ukraine
Combined Pumping of a Compact HCN-Laser with the Duplex Laser Radiation Output

An HCN-laser with the length of an active zone of 0.5 m has been described. The polarization-and-energy characteristics have been studied which depend on the electromagnetic parameters of output mirrors made in the form of two crossed one-dimensional wire gratings.

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V.V. Lysak and I.A. Sukhoivanov
Kharkov National University of Radio Engineering and Electronics,
14, Lenin Ave, Kharkov, 61166, Ukraine
Determination of the Optical Gain of III-V Group Compounds for Simulation of Laser Dynamic Characteristics Over a Wide Range of Radiation Frequency

The analysis of optical gain as a function of electron concentration, thickness and material of an active region in quantum-well structures has been carried out. The approximate expression is derived which describes with greater accuracy the amplification at various values of thickness of the active layer. The numerical values of the expression for various binary compounds are obtained. The validity of the calculation data is confirmed through comparison with previously obtained data.

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M.I. Dzyubenko, S.M. 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
Examination of Pulse-Periodic Radiation Source Tunable in Ultraviolet Spectral Region

The effect of the emission parameters of tunable flashlamp-pumped dye lasers on the second-harmonic generation in different regions of a spectrum has been studied. The requirements for the radiation divergence of dye lasers have been found to become more stringent as the spectral line width increases. The pulse-periodic source tunable in the ultraviolet spectral region (260-340 nm) has been designed and developed. The average power of this source is equal to a few tens of mW, while peak power is of several kW.

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