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1.  Integral representation of green function in parallel-plate and rectangular waveguide, and in resonator as well
V.A. Katrich, F.S. Novokhatsky
waveguides, Green function, fundamental solution, radial function, elliptical teta- function, image method, calculus of residues, integral transformation, grating, formal variative
Vestnik KhNU 712 Pages. 67-70

The known results connected with Green function representation by elliptical theta-function are generalized. New representations of Green function for some widely used types of waveguides are obtained. Earlier, these Green functions are presented either in form of series with nonuniform convergence or in form of integrals containing Hancel functions, which are reduced to asymptotic expressions in far zone. On this work integral representations of Green functions are obtained for Cases where the quadrature formula exists. The method of analytical continuation with parameter is applied

N.P. Zhuck, V.I. Fesenko, S.N. Shulga, O.V. Bagatskaya, He Shi
scattering matrix, rectangular waveguide, anisotropic medium
Vestnik KhNU 756 Pages. 33-37

The problem of determination of the scattering matrix coefficients from anisotropic inclusion in one side short-circuit waveguide was considered. Calculation of the scattering matrix coefficient |S10| for the anisotropic slab in the end of the empty rectangular waveguide is presented

3.  Radiolocation complex for extra-atmospheric researches
A.F. Sorokin, A.A. Sorokin, N.N. Gorobets, O.V. Sokolova
radar, a, microwaves, space garbage
Vestnik KhNU 834 Pages. 25-30

The creation pulse radar is offered on the basis of radio engineering systems of the National centre of management and test of space means of Ukraine for the forecast asteroid of danger, cataloguing of space garbage, research of a solar crown, near a sun and interplanetary plasma, and also for radioastronomical researches of distant space. Is shown, that at use of large-sized aerials to a ADU - 1000 and P-400 such radar at length of a wave ~ 30 cm at heights ~ 105 finds out objects with the minimal sizes ~ 0,7 cm. On a disk of the Sun the spatial sanction ~ 103 kms

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4.  Capacitance-voltage measurements in selectively doped ALGAAS/GAAS heterostructures
N.B.Gorev, I.F. Kodzhespirova, E.N. Privalov
gallium arsenide, selectively doped heterostructures, Schottky barrier, barrier capacitance, capacitancevoltage measurements
Vestnik KhNU 853 Pages. 3-7

The dependence of the measured apparent capacitance of selectively doped AlGaAs/GaAs heterostructures on the amplitude of the measuring ac voltage is calculated numerically. An expression that gives the measured apparent capacitance as a function of the true capacitance and the above amplitude is derived. Using this expression and the results of the above numerical calculation, it is shown that capacitancevoltage characteristics of selectively doped AlGaAs/GaAs heterostructures, which feature steeply dropping regions, may be measured at moderately small amplitudes of the measuring ac voltage (of the order of 100 mV) at the expense of taking measurements at two different amplitudes

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5.  Inner partial mutual admittance of two overlopping longitudinal slots in a rectangular waveguide with dielectric layer parallel to narrow walls
A.A.Lyakhovsky, L.P.Yatsuk, A.F.Lyakhovsky
, layer, dielectric, slot, admittance, scattering parameters
Vestnik KhNU 853 Pages. 22-27

The expression for the partial inner mutual admittance of two longitudinal slots overlapping along waveguide longitudinal axis is obtained. The slots are cut in a broad wall of a rectangular waveguide filled with three-layered dielectric. The excitation problem is solved with the modified eigen waves method. As eigen waves of the LE and LM modes are chosen. The field in the source region includes the potential functions as well. Dependences of inner mutual admittance and scattering parameters on distance between two slots and frequency are investigated. The system scattering parameters calculated are in a good agreement with experimental data

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6.  HF ionosonde signal focusing by traveling ionospheric disturbances
Yu. B. Milovanov, V. F. Pushin, O. F. Tyrnov
traveling ionospheric disturbances, signal amplitude variations, Doppler frequency shift, focusing factor, computer simulation
Vestnik KhNU 853 Pages. 88-94

HF signal focusing due to linear and nonlinear wave disturbances occurring during monostatic ionospheric sounding is discussed. A technique is developed for estimating signal amplitude variation due to focusing based on beating amplitude measurements during significant Doppler frequency shift events. The intercomparison of measured and modeled variations in beating amplitudes, the focusing index, and Doppler frequency shift show a qualitative agreement. The simultaneous analysis of variations in the beating amplitude and the Doppler frequency shift makes the interpretation of measurements more definite, e.g., it permits the isolation of large scale disturbances traveling at approximately 1 km/s

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7.  Microstrip structures with photonic band gap
Fesenko V.I., Sukhoivanov I.A., Shul'ga S.N.
photonics band gap, microstrip, filter
Vestnik KhNU 883 Pages. 20-24

In this paper, it is presented a two-sided one-dimensional photonic bandgap microstrip structure. The structure is obtained by etching a one periodic pattern of circles in the ground plane of a microstrip line and variation of the characteristic impedance

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8.  The accumulation of gas in galactic objects
Sorokin A.A., Sorokin A.F., Zaharova M., Sokolova O.V., Gorobets N.N.
astrophysics, galactic objects, the accumulation of gas
Vestnik KhNU 883 Pages. 3-7

The mechanism of the accumulation of gas in the galactic objects submerged in the large-scale magnetic field is examined. As a consequence of the diamagnetism of the plasma subsystem of object, the stopper geometry of magnetic field with the radial electr

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9.  The xecl laser with the adjustable shape and duration of generation pulse
S.S. Anufrik, A.P. Volodenkov, K.F. Znosko
LC- contour, XeCl laser, excitation system, generation energy, pulse duration.
Vestnik KhNU 983 Pages. 3-10

The generation parameters of LC-contour excitation system are studied for electro-discharge excimer XeCl laser using a NeXeHCl mixture. A computation model is developed for finding the generation parameters. It has allowed us to calculate current, voltage and generation power oscillograms for all parameters of the electrical excitation system. The program of XeCl-laser modeling enables to calculate an electrons, atom and molecule concentrations, specific energy deposition in active medium also. By means of program Bolsig + calculation of rate coefficients of reactions with participation of electrons is executed. It is shown that generation of short radiation pulses (20 ns) and relatively long pulses (60 ns) is possible due to changing of LC- contour parameters. Energy of generation reaches a maximum at use of small values of peaking capacity, which are significantly smaller then value of storage capacity.

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10.  Impact of random variations of air hole diameters and random variations of the centers position of air holes on operation parameters of a solid core microstructured optical fiber
A.I. Filipenko, A.N. Donskov
finite-element method, Gaussian distribution, inclusions diameter, total mode field power, angular positioning, microstructured optical fiber.
Vestnik KhNU 983 Pages. 29-32

We investigated the impact of random variations of air hole diameter and random variations of the centers position of air holes on operation parameters in the case of solid core microstructured optical fiber with a ring of air holes. The found results show that at any of considered defect types mode field will have two pronounced maximums. At practical use an investigated type of the MOF special angular positioning end faces of fibers is necessary. We also have shown that random variations of inclusions diameter can increase total mode field power. In our research we used finite-element method.

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