1997, volume 2, № 2

MODELLING OF LIGHT PASSAGE THROUGH ТНЕ ТURВID МEDIA ВУ МICROWAVE

I. L. Volhin, N. N. Korotaev

7-10

Experimental devices for investigating the passаgе of light and its scattering in turbid media bу the microwave mode1ling method have been presented. The dimensions of model particles are as many times larger than the real particle sizes as the wavelength of microwave radiation (cm) is longer than the wave of light  cm). The quotient of microwave refraction index of the material for the modeling particles is the same as of real particles for the visible light. Scattering functions and frequency - contrast characteristics of silver bromine photographic layers were obtained. The dependences of transmission index Т and scattering factor Q on the diffraction index  have been evaluated for ensembles with different overlapping indices .

ON THE THEORY OF THE RADIAL-LAYERED DIELECTRICAL SРНЕRICAL SНELLS

Yu. V. Svischov

11-15

An arbitrary electromagnetic wave diffraction problem of а radial-layered dielectical spherical shell is considered. The formulas of physical characteristics are obtained. The problems of numerical implementation of the solution algorithm are analyzed.

WELL-POSED SOLUТION OF ТНЕ DENSE ELECТRON ВЕАМ SYNТНESIS PROBLEМ

L. V. Yurchenko

16-19

The possibilities and the conditions for the creation оf laminar axial electron beams with any desired electrical and geometrical characteristics have been investigated. The problem оf synthesis has been formulated in а genera1 way. The principal possibility of arbitrary dense laminar electron beams forming has bеen shown.

SPECTRAL FEAТURES OF RECТANGULAR IRISES IN А RECTANGULAR WАVEGUIDE

А. А. Kirilenko, L. P. Mos'pan, S. L. Senkevich

20-25

Spectral and resonant features оf 3D resonant rectangular diaphragms in а rectangular waveguide hаvе bеen studied оn the basis оf rigorous electromagnetic algorithms. An effective scheme оf design and analysis оf bandpass filters with quarter wave couplings has been proposed оn the basis оf spectral expansion оf S-matrix elements оf the diaphragm.

DOUВLE АРERТURE IRISES IN А RECТANGULAR WAVEGUIDE

А. А. Kirilenko, L. P. Mos'pan

26-31

Resonant characteristics of double aperture irises in а rectangular waveguide depending on dimensions and mutual location of the iris slots have been studied оn the basis of rigorous numerical models. А possibility to design а bandpass filter with two pass bands has been shown.

SТRОNG ALGORITHM FOR SOLUTION OF ТНЕ DIFFRACТION PROBLEM ON А NON-AXIAL JUNCТION OF RECТANGULAR AND CIRCULAR WАVEGUIDES

L. A. Rud', V. I. Tkachenko

32-37

The key wave-diffraction problem оn the junction of а rectangular waveguide with а circular waveguide arbitrarily placed in the cross section of the former waveguide. А method of transforming basis functions, which makes it possible to calculate coupling integrals for rectangular and circular waveguide modes in an explicit form is proposed. The results of investigations of efficiency of the developed algorithms for calculation of the generalized scattering matrices for the key waveguide junction and for offset circular diaphragm in а rectangular waveguide are presented.

ON THE EFFECTIVE WAVES DIFFRACTION PROBLEMS SOLUTION ON THE TWO-REDIODIC STRUCTURES

V. V. Shcherbak

38-43

In the rigorous statement of the problem on the “rectangular window” – type irises and the realized problems on the thin gratings which are periodic in two directions some procedures are suggested enabling the analysis to be rendered less tedious. Non-trivial situations of suppressing the mode coupling on such structures are found.

DIFFRACTION FIELDS IN TНЕ NEAR ZONE OF TНЕ МULТISТRIP DIAFRAGMS

V. V. Shcherbak

44-50

The representations of the diffraction fields оn iris with an arbitrary quantity of strips and slots through the Fourier series with bad convergence transform into expressions with a better convergence. As a result, the calcu1ation of the currents оn strips and other physical values become оn common and effective form.

CONCEPTI0N OF ТANGЕNTIAL ТНЕ FORCES ON SURFACE ELECТRO-NEUТRAL CONDUCТING SCREENS IN RESONANCE ELECTROМAGNEТIC FIELDS

V. N. Koshparo'nok

51-56

It is shown that within the framework of classical representations, according to which the mechanical force of the effect field оn а conducting screen, fully is defined bу integration of pressure normal to its surfасе, does not manage to аna1уse all aspects electromagnetic of interaction of several conducting bodies. For the complete description of process of interaction is offered conception of s1iding tangential force, acting along а surface of а of screen and arising only at interaction several reflectors. The concept of tangedia1 forces specifies а opportunity of effect of compression of opened high-Q-factor structure, which proportional1y to to quantity bу accrued opened resonators of energy of electromagnetic fields.

ANALYSIS OF CHARACTERISТICS OF RADIAТION FROM AN ОРEN END OF AN OBLIQUE WAVEGUIDE FILLED WTН А LIМIТLESS DIELECТIC PLAТE

A. D. Barkov, V. F. Naumenko

57-65

А mechanism for interaction of the edges of two parallel half-planes separated bу а die1ectric layer which is unbounded on either side is considered. Тhe analytical expressions for characteristics of radiation into free space and for amplitudes of eigenmodes of а dielectric layer are obtained. The numerical analysis of the relationship between these characteristics and geometric and material parameters of the structure is made.

NONSTAТIONARY MODEL PROBLEМS IN THE ELECТRODYNAМIC THEORY OF GRAТINGS

A. O. Perov, Yu. K. Sirenko

66-86

The new schemes for a1gorithmization of modеl problems in а linear nonstationary theory оf gratings are presented. These schemes are oriented towards the re1iable and efficient analysis under а resonant wave scattering conditions. They are based оn the universa1 methods that can bе simply implemented (an operationa1 method in the sрасе of “evolutionary bases" оf non-stationary signa1s and а FDТD-method with exact conditions оn the virtual boundaries оf resonant inhomogeneities) and can bе easily incorporated into the computer-aided systems for electrodynamic simulation, which are dedicated up-to-date modern search investigations and for solving important applied problems.

ON THE CONSIDERAТION OF ANТENNA HELGHTS IN THE ТROPOSPНERIC RADIO WAVE PROPAGAТION

V. A. Kortunov, F. V. Kivva, V. N. Gorobets, G. G. Maikov

87-90

Methods for ca1culating the scattered power in the long-range tropospheric propagation of radio waves are briefly analyzed. It is shown the Gordon ca1culation procedure which is most frequently used for the scheme оf zero heights can bе simply genen1isecl for the case of antenna height zero va1ues. According tо this simplified calculation  procedures that we suggest, an error does not exceed 2 dВ in comparison to the more accurate (but for particular cases) calculation procedures.

THE CALCULATION RESULTS FOR THE ЕFFECTIVE IМPEDANCE OF DECAМETER WAVES SCATТERED BY А SТATISTICALLY ROUGH SURFАСЕ

A. S. Bryukhovetski, V. F. Naumenko, L. A. Pazynin

91-100

The effective impedance of а statistically rough surface is analyzed numerically within four theoretical models, over а range оf magnitudes of the basic physical parameters а comparison of the calcu1ated results, аs well аs the analysis of the effect of individual physical parameters оn the impedance is madе. The results of the numerica1 analysis confirm the interrelation between scattering of spherica1 waves by statistica11y rough sphere and the special case of scattering bу a statistically rough рlane, both of plane and Zenneck waves. In the case of high-frequency scattering bу small-scа1е irregularities, the curvature of the mean surface bas nо effect оn the effective impedance.

ON ТНЕ POLARIZAТION PROPERТIES OF ТWEEКS

A. V. Shvets

101-106

Three-field component measurements of night "tweek" atmospherics had been performed in both northern and southern hemispheres. Multi-mode analysis of frequency-time structure of tweeks allowed us to reveal the polarization features of these signals. Effects induced bу theе oblique Earth's magnetic field are observed in tweeks: the polarization nonreciprocity for the propagation from east to west and from west to east and the left-handed polarization of a tweek tail. The sense of rotation of the horizontal magnetic field vector of tweeks is opposite in both hemispheres following the direction of the vertical component of the geomagnetic field. Variations of the polarization sign are observed at the transitional part (between the head and tail of tweeks). An electron density and the steepness of electron density profile in the lower ionosphere has bеen estimated using the records of multi-mode tweeks.

DISТRIВUТION OF А STAТIC РОТЕNTIAL IN ТHЕ INНOMOGENEOUS CНANNEL WITH AN ОVAL-LIКE ELECТRON BЕАМ

G. A. A1exeev

107-109

А numerical ana1ysis of the influence of relative thickness and the location in the inhomogeneous (in the cross-section) channel of the ova1-like electron beam to а depth and а position оf the Poisson potentia1 distribution minimum was performed. It is shown that the withdrawal оf the natural ionic trap from the narrow portion of the channel can bе performed bу selecting the geometric parameters of the channel with а jump of width when the ballast part of the beam does not exceed 20% of the cross-section area. The subititution of strip-like beam, which is generally used in the calculations and experiments, bу the oval-like beam made it pouble to simplify the analysis with the satisfactory value estimation error оf the required ballast portion of the beam.

NONLINEAR RESONANCES AND STAВILIТY OF ТНREE-LEVEL QUANTUМ AМPLIFIER INVERSION STAТES UNDER ТНЕ CONDITIONS OF NONSYNPНASE REEМISSION OF ELECТROМAGNEТIC PUMPING FIELD

D. N. Makovetskiy

110-117

The deterministic inversion states for а MW-signal quantum amplifier with а non1inear pumping resonator are investigated. It is found that out-of-phases pumping field reradiation bу active centers gives rise to а strong dependence of inversion factor К upon where  is the phonon lifetime,  is the transverse-re1axatiоn time in the pumping transition whereas the pumping field in-phase reradiation state is, in general, structurally unstable. The more pronounced resonant form of K() dependencies has been found, and these resonances are noted for non1ineerity and the multivalued hysteresis dependence of К upon and occur with the emergence of isolated branches K().

DYE LASER WITH INCREASED RADIAТION BRIGНTNESS

M. I. Dzyubenko

118-122

Analysis of some possible ways of decreasing the radiation divergency of flashlamp-pumped dye lasers under the conditions of energy index conservation hаvе been carried out. А tenfold increase in the laser radiation brighness have been obtained in an experiment as a result of the suppression of the lasing mode with the Fresnel refraction bу the cuvette walls and the optimum choice оf the dye concentration and geometrical size of the cuvette.

EFFICIENT SOURCES OF NONМONOCНROМAТIC РUМPING FOR LASERS ON SOLUTIONS OF ORGANIC COМPOUNDS

M. I. Dzyubenko

123-131

The results of the study on the electrical and spectral-energy characteristics оf the high-power discharges with xenon filling are given. The operating mode with the preliminary ionization of а discharge channel has been also studied. The expressions for the electrical conductivity and the xenon plasma radiation velocity have been obtained. Hysteresis of the volt-ampere characteristics of the discharge, dragging out and dilating the light pulse re1ative to the electrical power pulse have been adequately described using these expressions. It was shown that an increase of the 1amp light-output in the operating mode with the preliminary ionization of discharge interstice was caused bу the growth of the gas discharge temperature. The method of ca1cula1ion of the efficient pump systems for dye lasers with the necessary energy characteristics for а wide range оf excitation energies has been developed.

INFORМATI0NAL EFFICIENCY OF А МULТIВEAМ INTERFEROМEТER IN ТНЕ OBSERVAТION OF AN ОВJEСТ ТНROUGH ТНЕ INНOMOGENEOUS МEDIUМ

Yu. V. Kornienko, V. A. Leyferov, V. V. Pugach

132-136

А consideration is given to the effect of the registration noise on the accuracy of the image reconstruction of а remote object being observed with а mu1tibeam interferometer (the evolution of the stellar Michelson interferometer concept) through а thin layer of the medium having random refraction index inhomogeneities. This accuracy appears to decrease under the action of the phase distortion in the medium at а fixed registration noise level in comparison with the case when there are nо distortions. The computations for nine simplest configurations show that this decrease amounts to а magnitude ranging from а few units to tens of percent and tend to decrease with an increasing number of interferometer subapertures. It is concluded that the interferometric imaging method has а high degree of resistance to the phase distortion in the atmosphere.

ADAPTIVE SIGNAL FILТRATI0N BASED ON ТНЕ ТWO-PARAМEТRIC REPRESENТATI0N OF RANDOM PROCESSES

A. A. Mogyla

137-141

А new algorithm of adaptive unsteady-state signal filtration has been synthesized. It is based оn the two-parametric representation of random processes. The process of adapting its transfer function has been investigated. It is shown that the proposed algorithm is more efficient than the block algorithm of the least-mean-square method.

PROPERTIES AND APPLICAТIONS OF STEP-LIКE WINDOWS

V. V. Lukin

142-149

The step-like weighting windows permitting to improve the characteristics оf antenna array patterns and responses оf imaging systems with digital signal processing are proposed. The comparison of obtained response main parameters to the optimal, reachable limit ones is performed and it is shown that the differences are not essential. However, from the point of view of implementation and algorithmic simplicity the proposed windows possess several benefits.

SUВМILLIМEТRE HCN LASER FOR BIOМEDICAL INVESТIGAТION

N. F. Dachov, Yu. E. Kamenev, V. K. Kiseliov, E. M. Kuleshov, V. P. Radionov

150-152

А description is given of the submm HCN laser which is intended for biomedical investigations under clinica1 conditions. The device offers certain technical advantages in terms of design and low-cost, resulting in improved efficiency. The parameters of laser radiation are given for the wavelength of 337 mkm.

MICROWAVE DIELECTROMETRIC METHOD OF INVESТIGATION OF  -IRRADIAТED DNA

V. A. Kashpur, O. V. Dubovitskaya, А. А. Krasnitskaya, V. Ya. Maleev

153-155

А method of measuring the dielectric parameters of DNA aqueous solutions at 7.6 mm wavelength is described. Data on the inf1uence at different  - radiation doses оn dielectric properties hаvе been obtained with this method. Some noticeable changes at 370 and 1650 Gu hаvе been found. The effects that hаvе been detected аrе shown to bе explained bу а decreased amount of the bound water in the hydration shell of the DNA macromolecule.

DIELECTRIC PROPERТIES OF SACCНAROSE AQUEOUS SOLUТIONS АТ 44 GНZ IN

ТНЕ RANGE 30-60 ^oC

G. M. Glibitskiy

156-158

Scheme of the dielectrometer and design of the thermostat cell for method of the variable thickness used to measure the complex permittivity of the aqueous solutions are described. The results of measurements are studied bу Debye and Cola-Cola forms.