1. Multifunctional measuring platform for investigations parameters of metal-dielectric structures
V.A. Katrich, D.V. Mayboroda, S.A. Pogarsky, I.I. Saprykin
automation complex, dielectric image guide, energetic characteristics
Vestnik KhNU ¹712 Pages. 21-24
The multifunctional automation measuring platform for ultra high frequencies parameters definition has been de- signed. The basis of this complex is the controlled mechanical platform which allows to measure the field amplitudes along two orthogonal coordinates. The processing of measuring date realizes with the help of special software. The measuring of energetic characteristics of radiating module based on dielectric image guide has been carried out
2. Radiation of transient fields from the open end of coaxial waveguide with shifted internal conductor
N.N. Gorobets, A.N. Dumin, O.A. Dumina
transient field, coaxial waveguide with shifted internal conductor, TEM-wave, radiation
Vestnik KhNU ¹712 Pages. 42-46
The problem of the radiation from the open end of coaxial waveguide with shifted internal conductor excited with transient source is solved in time domain. The incident into the aperture TEM-wave in coaxial waveguide with time dependence in form of gaussian pulse is considered as a source. The influence of a flange on radiated field characteristics is examined. The application of dielectric insertions into the aperture for the increasing of radiation along normal to aperture is studied
3. Application of the digital holographic interference microscope for investigation of human red blood cells 3-D morphology
T.V. Tishko, V.P. Titar, D.N. Tishko
digital holographic interference microscope, erythrocyte, morphology, sphericity coefficient, diagnostics, micro-object
Vestnik KhNU ¹712 Pages. 52-55
Results on the digital holographic interference microscope for 3-D imaging of native blood erythrocytes are presented. Blood samples of healthy people and patients with different pathologies were used. Three basic morphology kinds of blood erythrocytes were detected. A sphericity coefficient was used as quantitative characteristics of blood erythrocytes morphology. It is shown that, blood erythrocytes 3-D morphology is very important diagnostics characteristics in medical practice. The digital holographic interference microscope is an effective device for the purposes of medical diagnostics
4. Electromagnetic wave detraction on a resistive unclosed cone
V.A. Doroshenko, O.G. Litvinova
diffraction, resistive, longitudinal slots, an integral transform, analytical solutions
Vestnik KhNU ¹712 Pages. 95-99
Problem of harmonic electromagnetic wave diffraction on a resistive cone with longitudinal slots is considered. The boundary problem solution uses the Kontorovich-Lebedev integral transform and a semi-inversion method. Analytical solutions are obtained for the cone with a lot of narrow slots and reactive impedance. Impedance and longitudinal slots effects on scattering field structure is studied
5. Impedance of connected in series diodes with difference negative conductivity
tunnel diode, negative conductivity, frequency range
Vestnik KhNU ¹712 Pages. 111-114
The impedance connected in series negative difference conductivity diodes in wide frequency range are analyses. There are frequency region that diodes combination work have been appeared. The operation frequencies for combination of tunnel diodes are 35-40 GHz
6. GaAs-Gunn diodes with small levels of power constitution for mm-range oscillators
E.D. Prokhorov, A.V. Dyadchenko, N.E. Polyansky
Gunn diodes, microwave powers, efficiency, generators mm-range
Vestnik KhNU ¹712 Pages. 115-118
Experimentally investigated small level operating power GaAs generators mm-range. Samples of diodes made in Problem laboratory of semiconductor engineering of the Karazin Kharkov National University. GaAs -Gunn diodes oscillators operated in continuous mode. The obtained experimentally operated powers made 10...30 mW, the useful microwave powers - 0,1...0,3 mW at an efficiency of 1...2 % over the range frequencies of 60...75 GHz. Probably further reduction consumed by diodes and oscillators of power up to hundreds and tens 10-3W
7. Same question of modeling of tunnel contact semiconductor structure
O.V. Botsula, E.D. Prokhorov
tunnel cathode, negative differential conductivity, contacts, current - voltage characteristics, cathode, anode
Vestnik KhNU ¹712 Pages. 119-122
Electronic processes are considered at course of a current through semi-conductor structure with the tunnel cathode. The approach to modelling the structures including as a component tunnel geterojunction is offered. Static characteristics of structures to a basis geterojunction GaAs/AIGaAs received with application of the offered technique are resulted
8. The spectrum of current oscillations of Gunn diodes with the impact ionization in moving domains
D.V. Pavlenko, E.D. Prokhorov
Gunn diode, impact ionization, UHF-noise
Vestnik KhNU ¹712 Pages. 123-126
The results of the numerical simulation of the GaAs Gunn diode with electric field strengths, enough for development of the impact ionization in the moving high-field domains, are presented. The form of current oscillations and frequency spectrums is in good agreement with experimentally measured data. It is shown that the Gunn diode, operating under conditions of the impact ionization, may be used as a source of wide spectrum UHF-noise
9. EXCITATION OF AN UNCLOSED CONE PLACED AT AN IMPEDANCE PLANE
V.A. Doroshenko, O.G. Litvinova, A.V. Sova
excitation, an impedance plane, cone, longitudinal slots, analytical solutions
Vestnik KhNU ¹756 Pages. 42-46
By using the approach that is based on applying the Kontorovich-lebedev integral transforms method and a semi-inversion method an excitation boundary problem for a cone with periodical longitudinal slots provided that cone placed at an impedance plane is investigated. It is showed that the problem under consideration is equivalent to solving a system of linear algebraic equations for Fourier coefficients of electromagnetic field components. Analytical solutions are obtained for a semi- transparent cone and special plane impedance. Impedance plane effects are studied
10. One-dipole inverse problem of magnetostatics for reconstruction of heart-torso electric activity from magnetocardiography measurements
Bagatskaya O., Butrym A., Durneva Yu., Shulga S.
Do not determinated
Vestnik KhNU ¹756 Pages. 47-50
Do not determinated
11. DESTRUCTION OF PULSE TRAINS IN WEAKLY NONLINEAR OSCILLATOR
chaos, dynamical systems, train pulses, quasi linear oscillator
Vestnik KhNU ¹756 Pages. 71-78
A study has been carried out on the transition of train of pulses via a weakly nonlinear oscillator. Conditions of destruction of such trains as a result of appearance of chaotic instabilities have been analyzed. Analytically conditions of the appearance of chaotic instabilities have been determined by using the method of secondary averaging.
12. The Gaussian beam scattering on the bounded sequence of alternate grates of dielectric bars
V.B. Kazanskiy, V.R. Tuz, D.V. Yudintsev
Gaussian beam, thick grate of dielectric bars, anisotropic layer, periodic structure
Vestnik KhNU ¹756 Pages. 83-86
The Gaussian beam scattering on bounded periodical sequence of thick grates of dielectric bars are investigated. Identification of discrete structure with appropriate thickness homogeneous anisotropic layer was carried out for define sequence basic element transmission matrix. The sequence scattering coefficients were written down via Mougin polynomials. The effects of form distortion, beam splitting into several beams, side shift of beam axe were shown. Their correlation with scattering coefficients phase and module angle dependence of separate grates was established.
13. Al0,3Ga0,7As/GaAs cathode transfer electron diode's efficiency
O.V. Botsula Prokhorov E.D, A.V. Dydchenko
doping, cathode contact, tunnelling, negative differential conductivity, oscillation efficiency
Vestnik KhNU ¹756 Pages. 97-100
The results of analyse efficiency of GaAs/ Al0,3Ga0,7As/GaAs GaAs/ Al0,3Ga0,7As/GaAs / GaAs cathode transfer electron diode are present. The space charge model are used. There are two region of negative differential conductivity of current - voltage characteristic are shown . The condition lead to oscillation due both region and oscillation efficiency have been determined.
14. Wide range mm-wave GAAS- oscillator with electronic frequency gliding
A.V. Dyadchenko, E.D. Prokhorov
oscillators, electronic frequency gliding, oscillating efficiency
Vestnik KhNU ¹756 Pages. 101-104
The wide range mm - wave GaAs oscillators with electronic frequency gliding are considered. The oscillator is operated up 60 to 70 GHz on second harmonic. The electronic gliding is perfomed to obtaine of 9 GHz change of frequency
15. AlN/AlxGa1-xN resonance tunnell diodes
D.V. Pavlenko, E.D. Prokhorov
nitrides, quantum well, NDC, oscillation efficiency.
Vestnik KhNU ¹756 Pages. 105-108
Double and threefold compounds of nitrides AIN/AIGaN resonance tunnel diodes using height of barriers are concedered. In the quantum well of diodes there are a plenty energy levels. Electron energy levels in quantum well with variable structure of interconnections AlGaN are determined. The current - voltage characteristics of resonance - tunnel diodes with number of levels in a quantum wall up to five has been calculated. The RTD can have up to five sites with negative differential conductance are demonstrated. The possible RTD oscillation efficiency on all sites of negative differential conductivity at difference barriers and quantum well's material are determined.
16. Influence of impact ionization on efficiency of rsca-diodes operation on basis of InN, GaN, AIN
D.V. Pavlenko, E.D. Prokhorov
nitrides, RSCA oscillators, oscillating efficiency, drift velocity
Vestnik KhNU ¹756 Pages. 109-112
The impact ionisation in RSCA diodes is considered on the basis of nitrides InN, GaN, AIN. Possible overvoltage on diodes and possible efficiency of generation are analyzed. It is shown, that at development of a impact ionisation in RSCA diodes in correspondence with the diffusion theory the considered materials are perspective for RSCA diodes for operation in centimeter and millimeter wavebands (voltage over threshold 3 ... 5 at efficiency up to 11 ... 13 %)
17. Amplitude and noise features of detectors a mm of range of lengths of waves on base of contacts a metal-semimetal BiSb
O.N. Sukhoruchko, V.T. Plaksiy, E.D. Prokhorov, A.V. Dyadchenko
contact metal-semimetal BiSb, power zones, contact a metai-semimetal BiSb, millimeter range of lengths of waves, relative noise temperature, influence of displacing and resistances of contacts on sensitivity
Vestnik KhNU ¹756 Pages. 113-117
In work are brought results of analytical and experimental thermoelectrical detector study with the point contact a metal-semi-metal BiSb. Determined relative noise temperature, as well as influence of displacing and resistances of contacts on the sensitivity in 8 mm range of waves.
18. SPECKLE – INTERFEROMETRICIAN METHOD FOR ANEMOMETRICIAN OF TURBULENT STREAMS
G.N. Dolya, À.N. Katunin, Ê.V. Sadovy, S.I. Shmatkov
, speckle – interferometrician, anemometrician, speckle – painting, light-reflecting coverage
Vestnik KhNU ¹756 Pages. 118-122
In this paper is researched the possibility of the use of the modified speckle – interferometrician method for anemometrician of turbulent streams. It is developed laser anemometer on the basis of the modified speckle – interferometrician method at the applications of light-reflecting coverage. Is dependence of increase of border frequency of signal’s spectrum at growth of speed of stream transversal to the ray. Dependence of spectrum of fluctuations the adopted signal on the degree of the brought distortions in at a different temperature of turbulent stream is explored
19. SELECTIVE excitation of the HIGH-order MODES IN THE waveguide quasioptical RESONATOR
A.V. Volodenko, O.V. Gurin, A.V. Degtyarev, V.A. Maslov, V.A. Svich, A.N. Topkov
waveguide quasioptical resonator, excitation of the high-order transverse modes, an amplitude filter, Fourier optics
Vestnik KhNU ¹756 Pages. 123-131
The method of the space Fourier-filtration for selective excitation of separated high-order transverse modes in the waveguide quasioptical resonator with a high discrimination degree of undesirable modes is proposed and realized. It is carried out numerical study of characteristics of some the lowest on loss transverse modes of the dielectric and metal resonators of the submillimeter laser from geometric sizes of reflectors and parameters of the space filter on the nonuniform mirror. Configurations of the amplitude-stepped mirrors for shaping the high-order transverse modes in the laser resonators containing waveguides and open parts are proposed
20. Directed and polarization characteristics of the aperture of the circular waveguide with impedance flange
N.N. Gorobets, V.M. Dakhov, I.V. Gorbach
microwave, antennas, waveguides, polarization, pattern
Vestnik KhNU ¹806 Pages. 3-7
The amplitude and polarization patterns of the radiator in the form of the aperture of circular waveguide with impedance flange, excited by the dominant wave, have been measured by the method of the indicator antenna with polarization plane rotation. It is shown that such radiators have an axial-symmetric pattern, a wide polarization pattern and a low level of side lobes.
21. CALCULATION AND MEASURING OF IMPEDANCE OF IMPATT-DIODE IN MILLIMETR WAVE
A.V. Arkhipov, V.T. Plaksiy, I.K. Kuzmichev, E.D. Prokhorov, A.V. Dydchenko, D.P. Chuechkov
millimeter wave range, impedance, IMPATT diode, conductance, susceptance
Vestnik KhNU ¹806 Pages. 59-64
The calculated and experimental results of the impedance of the impact avalanche transit-time (IMPATT) diode for the 8 millimeter wavelength range have been presented. The dependences of the IMPATT diode impedance as a function of the normalized amplitude î Ã the fundamental current harmonic of the p-n junction and frequency have been calculated and measured. The apparatus and measuring method of the conductance and susceptance of the IMPATT diode has been developed
22. HARMONIC GENERATION BY IMPACT IONIZATION IN CaN LSA DIOD
O.V. Botsula, D.V. Pavlenko, E.D. Prokhorov
LSA diodes, generation efficiency, nitrides, drift velocity, harmonics
Vestnik KhNU ¹806 Pages. 65-69
In this work an impact ionization in LSA diodes on basis of GaN is considered. Analytical calculation of typical times of passing of a number of the physical processes determining properties of the oscillator, and limitings imposed by them on frequency properties of the diode is submitted. It is shown, that at developing impact ionization in LSA diodes, according to the diffusive theory, the considered compounds are perspective for manufacturing LSA diodes for work in sm and mm - ranges (electrical pressure over threshold 3 … 5 times, at an efficiency up to 11 … 13 %). The results of calculation of efficiency of oscillators on basis of GaN LSA diodes are given at their work in modes on a base frequency and at a harmonic generation.
23. Selection of the high-order modes in the waveguide resonator by means a phase-shifting mirror
A.V. Volodenko, O.V. Gurin, A.V. Degtyarev, V.A. Maslov, V.A. Svich, A.N. Topkov
waveguide quasioptical resonator, excitation of the high-order transverse modes, a phase filter, Fourier optics, selection
Vestnik KhNU ¹806 Pages. 87-91
The method of the space Fourier-filtration for selective excitation of separated high-order modes in the metal waveguide quasioptical resonator with a high discrimination degree of undesirable modes is realized. It is carried out numerical study of characteristics of some the lowest on loss transverse modes for the metal resonators of the submillimeter laser from resonator geometric sizes and parameters of the phase filter on the nonuniform mirror. Configurations of the phase-shifting mirrors for shaping of the high-order transverse modes in the laser resonators containing waveguides and open parts are proposed
24. Application of the digital holographic interference microscope for investigation of thin films
D.N. Tishko, T.V. Tishko, V.P.Titar, Yu. A. Zadneprovskiy, A.S. Kuprin, I.A.Zgoda
digital holographic interference microscope, three-dimensional images, vacuum-arc method, thin AlN films
Vestnik KhNU ¹806 Pages. 99-102
For the first time the digital holographic interference microscope (DHIM) was used for investigation of thin films on transparent substrates. Three-dimensional images of AlN of thin films, deposited on acryl substrates by the vacuum-arc method have been obtained, their thicknesses have been measured. It has been shown that the DHIM can be successfully used for film surface quality checking, thickness and film damages parameters measurement.
25. Radiation of short pulses from the open end of waveguide
O.M. Dumin, O.O. Dumina, V.O. Katrich, Zheng Yu
transient field, modal basis method, evolutionary equations, impulse field irradiation
Vestnik KhNU ¹834 Pages. 63-67
The problem of transient electromagnetic field radiation from the open end of waveguide is solved in time domain by the analytical and direct numeral methods. The problem of impulse signal propagation in regular waveguide is converted to the finding of transient wave propagation operator by modal basis method. The application of the operator for the obtaining of time form of signal both for the time change in positive and in the negative direction permits to seek an arbitrary time dependence of field amplitude in any point of waveguide taking into account distortions due to wave dispersion. The correction of diffraction distortions of time form of wave and forming the short probe impulse on the waveguide aperture by the excitation of waveguide in the given cross-section by field with the previously calculated time dependence are considered . Numerical simulation of short impulse irradiation of layered medium with losses is carried out
26. Frequency multiplication at impact ionization in GaN-diodes
Î. V. Botsula, D. V. Pavlenko, E. D. Prokhorov
the GaN diode, coefficient conversion transducing, drift velocity, harmonics
Vestnik KhNU ¹834 Pages. 100-103
The frequency multiplication at impact ionization in transfer electron GaN diodes nave been considered. The coefficient conversion transducing increase if impact ionization in GaN diodes takes place have been demonstrated. For example, coefficient conversion transducing in second harmonic arrive at 40 %.
27. Cathode static domen in transfer electron devise
Î. V. Botsula, D.V. Pavlenko, E.D. Prokhorov
static domen, velocity – field characteristic, electric field strange
Vestnik KhNU ¹834 Pages. 104-107
The diode in which static cathode domen and under certain conditions impact ionization takes place has being considered. Transit time effect and noise oscillations takes place under impact ionization. The volatge to be lead to electric field strange abow 200 êÂ/sm (for gomogenues velosity – field characteristic in ower dides) have been derermened
28. Oscillation efficiency of TED diodes on the basis of nitrides
E. D. Prokhorov, O. V. Botsula, A. N. Zabazhan
AlN, GaN, InN-diodes, drift speed, oscillation efficiency
Vestnik KhNU ¹853 Pages. 15-21
Oscillation efficiency of intervalley transfer electrons diodes on the basis of nitrides (InN, GaN, AlN) is considered. Electric fields at peak oscillation efficiency are determined. The results have been compared to results for GaAs. The account of floatable potential in connections InGaN improves their power characteristics in comparison with power characteristics of these connections without taking into account floatable potential, maximal efficiency In0.8 Ga 0.2 sub>N and In0.5Ga0.5N diodes to compare to InN diodes on 30 % is higher (22 % to compare to 16,43 %) but at more high tensions of an electric field. The maximal oscillation efficiency is observed at higher electric fields than GaAs ( from 250 êV/sm for InN to 1000 kV/sm for AlN)
29. Single cone with longitudinal slots excitation by an impulse point source
A.V. Artyukh, y.A. Doroshenko, Y.D. Shimuk
impulse source, cone, longitudinal slots, analytical solution, numerical solution
Vestnik KhNU ¹853 Pages. 51-56
In this work the excitation of a semi-infinite perfectly conducting cone with periodic longitudinal slots by an impulse radial source problem is investigated. The solution of the well-posed initial-boundary problem is found using an analytically numerical method based upon Green function and Meler-Fock integral transforms applying. It is shown that the original electrodynamic problem is equivalent to the one of the Fredholm linear algebraic equations system of the second kind solving. Analytical view of the solution is derived and the graphs illustrating the field dependence on the aperture angle and angle slot width are presented
30. Algorithm of a pulse signals delay definition, based on a Hilbert's transformation
D.O. Batrakov, D.V.Golovin, S.V. Grekov, A.G. Batrakova*
pulse signals, definition of a delay of signals, Hilbert's transformation, plane-layered media, thickness measurements
Vestnik KhNU ¹853 Pages. 71-76
In the present paper the algorithm of processing of the pulse signals reflected from plane-layered media is offered. It is supposed, that an effective thickness of layers less than spatial size of an impulse. This feature of a problem complicates use earlier proposed methods of signals time delay evaluating. Therefore in paper the theoretical analysis of possibilities of various approaches for processing of signals is carried out and the algorithm and the corresponding software for definition not only a time delay, but also physical and geometrical characteristics of investigated objects are offered. Results of numerical modelling and experimental researches for the purpose of definition of sensitivity and resolution of a method, and also possibility of its practical use are given
31. Analysis of impulse fields reflected from layered medium with losses using artificial neural network
Shyrokorad D. V., Dumin O.M., Dumina O.O., Katrich V.O.
time domain, artificial neural network, impulse fields, layered medium
Vestnik KhNU ¹883 Pages. 35-40
The problem of determination of thickness a layer of layered medium by impulse irradiation is solved. The impulse fields reflected from the layered medium with electrical characteristics close to the characteristics of human skin are analyzed by artificia
32. Experimental study of diffraction of electromagnetic waves on the lattice of elements of the complex profile
Ivanchenko D.D., Maleev M. N.
the difraction electromagnetic waves, chiral grates, frequency-poiarization property
Vestnik KhNU ¹883 Pages. 54-58
In given paper the diffraction of electromagnetic waves on volume grid is investigated experimentally. The grid consists of rectangular elements. Two planes of two-dimensional periodic rectangular metallic string elements located on both dielectric surfac
33. FREQUENCY MULTIPLICATION AT IMPUCT IONIZATION IN TRASFER ELECTRON DIODES ON BASIS AlN, InN
E. D. Prokhorov, O.V. Botsula, I. A. Grishchenko
AlN, GaN, InN diodes, frequency transformation factor , drift velocity, harmonics.
Vestnik KhNU ¹883 Pages. 30-34
Multiplication of frequency at impact ionization in intervalley transfer electron diodes on basis InN, AlN is considered. The current – voltage characteristics of intervalley transfer electron diodes have negative conductivity region and strong increasing
34. Investigation of different temperature modes of auxilliary cathode work in magnetrons with cold secondary-emission cathode
Avtomonov N.I., Vavriv D.M., Sosnytsky S.V.
Magnetron, cathode, thermionic cathode, thermo emission, temperature
Vestnik KhNU ¹883 Pages. 73-82
A theoretical investigation of the emission current temperature dependence of the auxiliary cathode in magnetrons with cold secondary-emission cathodes is performed. Different methods of providing a spatial-charge limited emission from the auxiliary catho
35. Dielectric permittivity profile reconstruction by frequency probing problem for a plane-layered media with regard to dispersion
Batrakov D.O., Simachov O.A.
plane layered media, dispersion, inverse problem, dielectric permittivity
Vestnik KhNU ¹883 Pages. 45-49
In the present paper the problem of dielectric permittivity profile reconstruction with regard to dispersion is discussed. The nature of dispersion function is assumed to be known and unknown functions are real and imaginary parts of dielectric permittivi
36. Impedance characteristics of planar diodes with tunnel boundaries based on GaAs
Prokhorov E.D., Botsula O.V., Klimenko O.A.
: negative differential conductivity, tunnel boundary, a diode, the tunneling.
Vestnik KhNU ¹966 Pages. 13-18
The impedance characteristics of the diodes are consider, which negative differential conductivity (NDC) is arise under cer-tain voltage, due to tunneling of electrons through the side faces of the diode, which can be used for generation, amplification and multiplication. Depending on the active and reactive components of impedance are determined of the diode with the tun-nel boundaries for the real parameters of the diodes. It is shown that the limiting frequency of the diode NDC is in the tera-hertz range and depends on its parameters.
37. Determena Frequency properties of intervalley electron transfer in AlN
V. T. Plaksiy, À.V.Arhipov, À. S. Tischenko, Ò. ². Kamishanova, E.D. Prokhorov, À.V.Dyadchenko, D. P.Chueshkov
perfect crystal, zone overcrystallization, temperature gradient
Vestnik KhNU ¹966 Pages. 19-22
The problem of growing of perfect bismuth-antimony monocrystals having of a uniform distribution of Sb atoms through the crystal by help floating-zone refining method is considered. The expression for temperature gradient in melt and temperature distribution for any melt point have been obtained.
The monocrystals growing maximal velocity have been estimated. The growing velocity must be lower then 1 mm per hour was showed. It is velocity not lead to concentration overcooling and arising inhomogeneous dendrite structure. For solution with certain composition ( at = const) overcooling may be eliminated by either increasing of temperature gradient in liquid faze or decreasing growing velocity are showed.
38. New statistical methods of recognition and classification for automatic interpretation of remote observations
Koltunov Y.A., Dumin O.M., Katrich V.A., Naumov R.R.
methods of recognition and classification, blenderized models of the probabilistic distributing, teaching selection
Vestnik KhNU ¹966 Pages. 37-49
Mathematical models, computational algorithms, and also prospects of development and application of three new methods of recognition and classification (RÀC), namely, construction of distinctive characteristics of objects; classification on the basis of probabilistic teaching selection with optimization of method RAC; account of dynamics of features of recognized objects are presented in the article. Recognition and classification is an area of modern science that have a boundless list of applications in all spheres of human activity. From the list of applications the only one is selected in the present work, but the most actual one, that is the remote sensing of ground surface in radiofrequency band with the purpose of study and maintainance of natural resources of Earth.
39. The geometrical approaches to the calculation of propagation of Gaussian beams in hollow metal waveguides in the terahertz range
Gurin O.V., Degtyarev A.V., Maslov V.A., Svich V.A., Senyuta V.S., Topkov A.N.
metal waveguide, Gaussian beam, terahertz range, geometrooptical approach, transmission coefficient
Vestnik KhNU ¹966 Pages. 3-8
A comparison of the results of calculations of the transmision for Gaussian beams in hollow circular metal waveguide using geometrooptical procedures by Frost and Crenn with the results of experiments in the
terahertz range is performed. The conditions of applicability of these methods to study the transmission characteristics of metallic waveguides of different lengths were found. It is shown that in this range the geometrooptical approach, proposed by Frost, provides satisfactory results only for short waveguides, the length of which corresponds to the condition of the near zone. The geometrooptical approach by Crenn is applicable to both short and for long waveguides.
magnetocardiography, gradiometer, current dipole, sensitivity, Hessian
Vestnik KhNU ¹883 Pages. 25-29
The article considers hexagonal grid of gradiometer sensors of magnetic field. The aim of the study is to determine the optimal parameters of the grid and the gradiometers in order to obtain maximum sensitivity of the measuring system in terms of location of a pointwise dipole source of magnetic field in some spatial region. These parameters are the distance between adjacent gradiometers in the grid (base of the grid) and the distance between two coils within gradiometer (base of the gradiometer). The obtained results allowed us to formulate some recommendations regarding design of such magnetocardiographic measuring system.
41. 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 ¹983 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.
founded: 41 result (s)