2009, volume 14, № 2

A Thin Stepped Conductor in a Waveguide Cross-Section as a Simple Rejection Unit

A. A. Kirilenko, S. A. Prikolotin

119-127

The simple configurations of practically feasible rejection units placed in a rectangular waveguide cross-section are suggested. They are the thin stepped conductors, connecting the opposite waveguide walls. They form a kind of thin two-aperture irises easily placed, for example, between waveguide flanges. A rejection phenomenon is based on the interference interaction of the eigen oscillation fields of the iris with two L-shaped apertures. The rejection frequency and quality factor are controlled by the placement and the height of the conductor step over a wide range. The situation when a stepped perfect conductor provides the resonance of a nearly zero bandwidth is revealed. In other words, such a nontrivial 3D waveguide unit loaded on propagating waveguides is able to support an eigen oscillation without radiation loss.

ON QUALITY OF ELECTRICAL  EIGENMODES OF AN OPEN RESONATORS WITH SPHERICAL MIRRORS

Yu. V. Svishchov

128-132

The behavior of axially-symmetric electrical-type modes of an open resonator with spherical mirrors has been numerically investigated. It has been found that the diffraction quality can be increased (decreased) from one to two orders in the magnitude by varying geometrical parameters of the resonator. Degeneration points of resonator eigenmodes have been revealed in the complex plane.

Description of boundaries in scattering problems with the help of fractional operators

E.I. Veliev, M.V. Ivakhnychenko, T.M. Ahmedov

133-140

Possibility of utilization of fractional operators in reflection of electromagnetic waves from plane boundaries is analyzed. Fractional derivative and fractional curl operator obtained as a result of fractionalization of usual operators of derivative and curl are under consideration. A fractional curl operator can be used to describe effect of changing of polarization of wave reflected from bi-isotropic slab or boundary described by anisotropic impedance boundary conditions. The order of fractional curl operator is defined from material parameters of considered problem. Boundary conditions with a fractional derivative generalize conditions for perfect electric and magnetic conductive boundaries. Usage of fractional boundary conditions (FBC) to simulate reflection from plane boundaries. Scattering properties of a strip with FBC and an impedance strip are compared on example of diffraction problem by a strip of finite width. Equations that are relate a fractional order and an impedance have been evaluated. It is shown that FBC can be used to simulate scattering from impedance boundaries and also from a dielectric slab for a wide range of parameters. FBC correspond impedance boundaries with a pure imaginary value of impedance. Also special scattering features of a strip with FBC related with its superwave properties have been shown.

Wave transformation from statistically rough surface

F. G. Bass, L. B. Vatova

141-144

The generalized small perturbation method is applied to investigate the transformation of waves on statistically rough surface separating media in which several types of waves caused by a time and spatial dispersion propagate. The field boundary conditions have been formulated. The mean intensity of the transformed fields have been calculated.

THE RECONSTRUCTION OF THE TROPOPHERE NON-UNIFORMITIES SPATIAL SPECTRA BY THE CORRELATION FUNCTIONS OF AMPLITUDE FLUCTUATIONS

G. A. Alexeev, M. V. Belobrova

145-154

The method of the numerical solution of the inverse problem of the radio occultation by plane wave for the stochastically non-uniform troposphere is proposed. The method allows reconstructing non-uniformities troposphere spatial spectrum by the correlation functions of amplitude fluctuations of the geostationary satellite radio signals (or appropriate power spectra). The solution algorithm is based on the conversion into the equation with self-adjoint operator and using a-regularization method. It is shown that spatial spectrum may be reconstructed at the optimal values of regularization parameter for different troposphere models. The solution algorithm was used for spatial spectrum reconstructing on the experimental frequency spectra of the radio signal amplitude fluctuation.

The analysis of a high-altitude structure of atmosphere refraction factor above THE Black sea

V. A. Kabanov

155-158

The data on vertical gradients of factor of refraction in different in height and thickness atmosphere layers by results of refractometric measurements above the Black Sea are submitted. The weak interrelation of gradients on various sites of a high-altitude structure N(h) for concrete high-altitude distributions is shown.

FORGOTTEN MODEL OF LIGHTNING STROKE

A. P. Nickolaenko

159-164

We describe the model of the lightning discharge, which was developed in the USSR by Stekolnikov in 1940s. The model is practically unknown among western specialists in the atmospheric electricity. In the present paper the major parameters of the model are presented, the numerical modeling is performed and its results are compared with the commonly used models. We show that Stekolnikov’s model has definite advantages and occupies a sound position among the modern engineering models of lightning strokes.

BACKSCATTERING MEASUREMENTS FOR METALLIC UNCLOSED SPHERICAL SCREENS

D. D. Ivanchenko, I. O. Sukharevsky

165-168

Electromagnetic backscattering measurements for metallic unclosed spherical screens in the range of 26,2 to 38,4 GHz are presented. The radii and aperture of a spherical segment was equal to 18,08 and 12,55 mm, respectively. The sample was made by extrusion of aluminum foil with thickness 0,15 mm.

Frequency dependencies of the normalized radar back-scattering (RCS) diagrams were obtained for excitation of a thin spherical screen along the axis. A comparison of experimental data and known theoretical treatment for RCS are given. Backscattering behavior is studied in the wide range of frequencies and incidence angles.

STUDY OF DOUBLE FREQUENCY METHOD FOR REMOTE SENSING OF SOLID AEROSOLS

O. A. Voitovych, A. M. Linkova, G.  I. Khlopov

169-176

The analysis of double frequency method for measurement of particles dimensions is presented. Also results of numerical simulation of sounding process are represented based on rigorous solution of diffraction problem. Limits of the method applicability and influence of medium polydispersity are estimated.

Stop bands in magneto-photonic crystal in millimeter waveband

M. K. Khodzitsky

177-182

One-dimensional (1D) magneto-photonic crystal (MPC) with tri-layer cell (vacuum-ferrite-quartz) interfaced with wire medium (WM) was investigated at microwave band. The appearance of two stopbands associated correspondingly with wave interference in the MPC and with ferromagnetic resonance absorption in ferrite layer was demonstrated. The occurrence of surface waves for the MPC+WM system in the MPC stop band frequency range was shown theoretically and experimentally. The surface wave peak allows the tuning of its position with applied magnetic field. It was shown that the steepness of the curve describing the dependence of surface wave peak position on magnetic field is less than the steepness of the corresponding curve for the left edge of the MPC stop band. The considered effects will make it possible to develop new magneto tunable microwave devices on basis of magneto-photonic crystals for GHz and THz band.

PROGRESSIVE METHODS OF INCREASING AND CONTROL NONEQUILIBRIUM MINORITY CHARGE CARRIERS LIFETIME IN BASE CRYSTALS FOR HIGH-PERFORMANCE SILICON SOLAR CELLS

M. V. Кirichenko, R. V. Zaitsev, V. R. Коpach

183-189

The characters of nonequilibrium minority charge carriers lifetime τ_n,p  distribution along the thickness of single-crystal silicon wafers with p- and n-type of conductivity, intended for electronic technique hardware and exposed to such methods of the τ increase in their near-surface areas, as a gettering annealing and deep chemical etching, are presented. Such investigations were carried out by the improved method of stationary photoconductivity as well as by the standard method of photoconductivity decay. Using the exposed to deep chemical etching such silicon wafers as the base crystals for creation of resource-saving and high performance multijunction photovoltaic converters with vertical diode cells of new generation was suggested in the carried out comparative analysis results of received τ_n,p  values.

MAGNETORESISTANCE OF A NON-STATIONARY MAGNETIC TUNNEL JUNCTION

D. V. Abdulkadyrov, N. N. Beletskii

190-197

Tunneling of electrons through a non-stationary magnetic tunnel junction in approximation of small amplitude of alternating electric field has been investigated. Dependences of active and passive parts of a high-frequency electronic current density through a magnetic junction on the frequency and the applied constant bias voltage have been studied.

RESEARCH ON CoLD START process in MAGNETRONS WITH COLD secondary-emission CATHODE

N. I. Avtomonov , D. M. Vavriv , S. V. Sosnytsky

198-206

Theoretical analysis of auto-oscillations excitation mechanism in magnetrons with cold secondary-emission cathode and without auxiliary cathode has been performed. Auto-oscillations excitation by external UHF signal or modulation of anode voltage has been studied. Conditions of specified mechanisms implementation have been defined. Comparison of numerical modeling results and experimental data, obtained for millimeter wavelength band magnetrons, has been carried out.

HIGH-POWER NARROW-BAND TUNABLE impact PERIODIC DYE LASER

P. G. Dalchenko, M. I. Dzyubenkо, V. P. Pelipenko

207-211

Wavelength-power characteristics impact, periodic, two-stage laser, composed of signal generator and multipass amplifier, were studied. Conditionals of suppression broadband background and increase transformation efficiency energy into narrow injected line were defined. Findings are in agreement with theoretical conclusions.

High-power, narrow-band, tunable, impact, periodic dye laser with lamp pumping, guaranteeing average power radiation under 4 Wt under line width 0,1 nm and overlying spectral range 460–680 nm was created.

HARMONIC GENERATION AND FREQUENCY MULTIPLICATION IN CASE OF IMPACT IONIZATION IN THE GAN DIODES

О. V. Botsula, D. V. Pavlenko, E. D. Prokhorov

212-217

The impact ionization in GaN diodes has been considered. The considered compounds are perspective for using in mm and sub-mm wave range with impact ionization evolution in the diodes (bias voltage is excess over limit voltage five times and efficiency value is 11…13 %) have been demonstrated. The possibilities value of oscillation efficiency in harmonic oscillation modes due to GaN diodes has been demonstrated. The frequency multiplication due to impact ionization in GaN diodes has been considered. If impact ionization takes place, coefficient of frequency transformation increases and reaches, for example, 40 % for second harmonic.

RESEARCH OF EFFECT OF LASER GENERATION PULSE BIFURCATION WHEN HCN-LASER IS PUMPED BY ALTERNATING CURRENT

V. K. Kiseliov, V. P. Radionov

218-221

In terahertz HCN lasers, with pumping by alternating current with frequency 50 Hz, laser radiation is generated as pulses with frequency of following 100 Hz. A radiation pulse shape changes depending on variation of the resonator length within the generation zone. Each pulse of laser radiation can be transformed on two separate pulses. Frequency of pulses, thus, is doubled. The explanation of this phenomenon is given at the paper.

RECOVERING PHASE DISTORTIONS FIELD UNDER THE IMAGE OF POINT SOURCE

S. I. Skuratovskiy

222-228

The possibility of recovering complex function under the modulus of its fourier-transform is discussed. By means of computer experiment it is shown that it is possible to apply iterative reconstruction procedure developed for real images to complex function and the result will be obtained accurate to a constant phase factor. It is confirmed that in the general case the possibility of obtaining correct result is much less compared to real image reconstruction. Some practically-justified additional conditions must be used to rise the possibility of correct reconstruction.

UNIONIZING ELECTROMAGNETIC RADIATION AND ECOLOGY

A. M. Egorov, A. Yu. Lonin, Yu. F. Lonin, V. I. Chumakov, A. G. Shepelev, O. V. Nemoshkalo

229-238

The modern condition of electromagnetic ecological conditions is stated, the analysis of natural and artificial sources of electromagnetic radiation (EMR) and their characteristics are given. Medical and biologic, hygienic and ecological influence aspects of electromagnetic radiations both on the person and on ecosystem as a whole are considered. Results of experimental researches in IPENMA NSC KIPT on influence of ЕМR on medical and biologic objects are given.

CYLINDER RESONATOR WITH RADIAL CAVITY FOR COMPLEX PERMITTIVITY DETERMINATION OF TABLE WINES

Z. Е. Еremenko, Е. М. Ganapolskii, V. N. Skresanov, V. V. Vasilchenko, V. G. Gerzhikova, T. A. Zhyleakova, N. S. Anikina

239-249

The complex permittivity measurement method for small volume (of order of 1 ml) of high loss liquid at millimeter wave band was proposed. The method was based on the use of a resonance cell as a cylinder resonator with radial cavity filled with liquid under test. The characteristic equation that allows obtaining the complex permittivity of the liquid under test was determined by the use of experimental data (resonant frequency and Q-factor) and complex permittivity of the liquid taken as standard. The optimal resonator sizes, spectral parameters and the operating oscillation mode were determined to obtain complex permittivity of the high loss liquid that fills the radial resonator cavity. The given method was used for complex permittivity determination of various samples of table wines. The paired correlation coefficients of the complex permittivity of wine with its physical-chemical parameters were obtained.