2008, volume 13, № 1
IMPEDANCE METHOD FOR INVESTIGATION OF OPEN RESONATOR CHARACTERISTICS UNDER CONDITIONS OF HYBRID MODE EXCITATION
Glamazdin V. V., Skresanov V. N., Shubny A. I.
9-19
The method of account of the unloaded Q-factors, resonance frequencies, coupling coefficients with a transmission line and mutual coupling coefficient of two partial modes with closely located resonance frequencies excited in resonator has been offered. The method is based on the approximation of experimental or theoretical dependence of complex-valued reflection coefficient of a resonator by a rational function of the real variable that describes the inducted oscillation in two coupled circuits. The method is approbated by using of data of account of reflection coefficient of a quasioptical OR and applied to open resonator characteristic investigation under conditions of hybrid mode excitation.
ABOUT THE PURE TEn,0 WAVE CONVERSION BY HIGH ORDER ON THE CASCADE OF THREE PERIODICAL STRIP DIAPHRAGMS
Shcherbak V. V.
20-28
We consider problem about an optimization of cascades of periodic or quasiperiodic strip thin diaphragms as waves converters in rectangular waveguide. We obtain optimal constructions for pure energy transformation of the main mode ТЕ1,0 into ТЕn,0 with high order (n = 4 or 5 or more) and also between two different higher modes ТЕ2,0 and ТЕ3,0) The flat-topped frequency characteristics of mode-conversion are obtained.
INVESTIGATION OF THE MAIN QUASI-T-WAVES IN PREFRACTAL MICROSTRIP LINES’ SYSTEM
Koshovy A. G., Koshovy G. I.
29-33
The main quasi transverse electro magnetic waves are examined for prefractal system of micro strip lines. The problem is formulated in the form of the first kind integral equations` system with electro static kernels. Making use of the narrow strips approach the problem has been transformed to the eigenvalues` problem for two symmetrical matreses. The simplest systems with correspond to self similar fractals` generator with changing dimension are considered in details. Effective numerical algorithm has been developed and used for calculation of the main electro magnetic characteristics. Numerical results are presented as well.
ABOUT AN AXIAL INDEX OF THE EIGEN MODES IN QUASIOPTICAL DIELECTRIC RESONATORS WITH CYLINDRICAL SURFACES
Shipilova І. A.
34-39
The numerical investigations of cylindrical and radially two-layered cylindrical dielectric resonators with axially heterogeneous oscillations have been carried out. The frequencies and qualities values of the resonators with the modes different in their axial indexes were obtained. It is shown that the resonators have such modes where the quality factors are at the high. The relation between eigen modes axial and azimuth indexes of the resonators with maximums of quality factors has been analysed.
ELF ATTENUATION FACTOR DERIVED FROM DISTANCE DEPENDENCE OF RADIO WAVE AMPLITUDE PROPAGATING FROM AN ARTIFICIAL SOURCE
Nickolaenko A. P.
40-44
The distance dependence is demonstrated of the artificial ELF radio signal measured in the Atlantic. The wave attenuation factor was found at a discrete frequency. The value thus obtained is in accord with the literature data as well as with the model based on the Schumann resonance. Deviations lie within the standard error conditioned by the finite signal to noise ratio. The attenuation factor obtained might be used for testing propagation models in the Earth – ionosphere cavity. Absolute calibrations of measurements provided the effective current moment of the field source.
MODEL TRANSIENT ELECTRIC PULSES IN MESOSPHERE ABOVE THE BENT STROKE OF LIGHTNING
Kudintseva I. G., Nickolaenko A. P., Hayakawa M.
45-50
Pulsed electric fields were computed in the neutral atmosphere above a powerful positive bent (broken) stroke of lightning that contains vertical and horizontal sections, each 10 km long. We demonstrate the fine structure of the field arises in space owing to interference of delayed pulses arriving from the vertical and horizontal sections of the causative discharge. Particular distribution depends on time and on the bent stroke orientation in respect to an elevated observer. Characteristic size of ‘filaments’ in transient electric field was obtained about 1 km along the horizontal direction, and it reaches a few tens of kilometers on the height.
SURFACE POLARITONS AT THE ROUGH BOUNDARY CREATED BY THE RAYLEIGH WAVE
Yakovenko V. M., Khankina S. I., Yakovenko I. V.
51-57
It is shown that in propagating the Rayleigh sound a heterogeneous near-surface layer appears in the semiconductor. The thickness of this layer exceeds the sound localization region. The appearance of the layer is stipulated by the surface electronic states stimulated by the Rayleigh wave. The dispersion law of surface polaritons under heterogeneous near-surface plasma conditions is obtained and studied in this paper. It is shown that the properties of the polaritons depend on the frequency and amplitude of the Rayleigh sound.
APPLICATION OF COMPOUND ULTRASOUND RESONATOR FOR MAGNETIC MATERIALS INVESTIGATION
Khizhnyi V. I., Tarakanov V. V., Khizhnaya T. M.
58-64
A method of high-frequency ultrasound waves absorption and velocity dispersion based on application of a compound acoustic resonator has been described. This method is realized for investigation of small absorption variation and velocity dispersion of sound in iron borate FeBO3 with a thickness ~ 140 μm at frequency ~ 200 MHz.
PHENOMENOLOGICAL MODELLING OF MAGNETIC ORDER IN GRANULAR NANOSTRACTURE ON THE BASIS OF RESULTS OF ESR – EXPERIMENT
Bagmut T. V.
65-70
The phenomenological model describing the phenomenon of ferromagnetic resonance (FMR) in granular magnetic nanostructure is submitted. The model is verified on the example of study of magnetic properties of nanostructure amorphous dioxide of silicon with nanoparticles cobalt (SiO2) 100-хCoх/GaAs in the wide area of Co - concentration (х = 20, 30, 45, 49, 54, 63, 75 and 85% Co). It is shown, that magnetic clusters having the shape depended on the Co – concentration can be formed in granular nanostructure.
COMPETITION AND COOPERATION OF MODES IN SMALL-VOLUME DRO WITH PERIODIC STRUCTURE FROM COUPLED GROOVED WAVEGUIDES
Miroshnichenko V. S.
71-78
The singularities of excitation of oscillations in small-volume diffraction radiation oscillator (DRO) are surveyed. The examinations of singularities of a competition of modes in DRO in 8-mm waveband are carried out. The bifrequency condition of generations described by cooperative interaction of excited modes detected. The identification of resonant modes participating in cooperative interaction is carried out and the mechanism of origin of synchronous bifrequency conditions in resonant self-oscillators with distributed interaction is offered.
EXCITEMENT OF THE RESONANCE CLYNOTRONAT VERY SMALL ANODE VOLTAGE VALUE
Mil’cho M. V., Tischenko A. S., Zavertanniy V. V., Lopatin I. V.
79-86
The excitement of the resonance clynotron under an electron synchronism with –1, -2, -3 and –4 spatial harmonics of the slow-wave system field is investigated experimentally. The excitement occurred without the preliminary electron stream modulation of the start current by some milliamperes. A simple physical model of the interaction between the electrons and the comb slot resonator field is analyzed theoretically. It is shown that in the clynotron case the effective interaction between the electrons and the high-frequency field is possible even if the transit angle has a very high value. The prospect of using the studied regime utilizationat the sub- millimeter-wave clynotron for the comb period increase by several times is discussed.
EFFECT OF SMITH-PURCELL RADIATION ON ELECTRON BEAM IN DRO TYPE DEVICES
Khutoryan E. M., Tsvyk A. I.
87-93
The action of the Smith-Purcell radiation (SPR) on the electron beam in devices of diffraction radiation oscillator (DRO) type has been studied in theoretical terms. It has been shown that the SPR field exerts “radiation” deceleration on the beam. At a large space charge q, the “radiation” deceleration of the electron beam substantially changes the radiation pattern, the beam interaction power and other DRO characteristics. At a little q, the SPR actions on the beam can be neglected.
INFLUENCE OF THE DISSIPATION ON THE PROPERTIES OF THE CYCLOTRON WAVES IN THE SEMICONDUCTOR PERIODIC STRUCTURE
Bulgakov A. A., Kononenko V. K., Kostylyova O. V.
94-98
Influence of the dissipation in the semiconductor material of the semiconductor - dielectric periodic layered structure on the pass band contour of the eigen waves is investigated. It is shown that taking into account the dissipation gives rise to the occurrence of the turning of dispersion curves for the electromagnetic waves propagating in such a structure. At the same time the phase velocity minimum value is limited. It is found that when the collision frequency value is big one of the band edges in the cyclotron waves region is degenerate, i.e. the zone “destruction” takes place.
ON THE PHYSICAL PROCESSES IN THE PRODUCTION OF A SPACE CHARGE IN A HEATING-FREE MAGNETRON WITH FIELD EMISSION TRIGGERING
Gurko A. A., Yeryomka V. D., Naumenko V. D., Skripkin N. I.
99-104
Consideration is being given to possible physical processes in producing a volume charge in the interaction space of the heating-free magnetron with a main cold cathode and secondary-electron emitter triggered with primary electrons emitted by the field electron emitter of an ancillary cathode. A procedure is proposed for assessing the conditions under with the space charge restricted current regime occurs.
RESEARCH OF THE LOCALIZED WAVE PACKETS OF RYDBERG ATOMS
Derbov V. L., Teper N. I.
105-109
We present the results of numerical modeling of rydberg states laser excitation for localized wave packets forming. The action of linear and circularly polarized fields on atom was considered for different shape of pulse envelope. The form and properties of obtained packet, constructed from eigenstates with low values of orbital and magnetic quantum numbers, were analyzed. Takes place well agreements between our results and the results obtained other authors.
RECEIVING OF MULTIFREQUENCY SIGNALS IN DIFRACTION RADIATION OSCILLATORS
Kurin V. G.
110-113
The physical mechanism of the multifrequency signals formation, realized in cases of the excitation in resonant system of the investigated oscillator of the highest mode, which form of the some variations ("spots") of a field along a direction of the electron beam moving is considered. The electron beam moving through such chain of the field spot (“the connected resonators chain”) was accompanied by excitation of the many automodulated mode and, accordingly, transition of the oscillator operation in the multifrequency mode. The output signal spectrum structure could be operated effectively by the anode voltage change.
NEUTRAL IMPURITY AND ALLOY POTENTIAL SCATTERING PART OF ELECTRONS IN FORMATION OF VOLUME CHARGE WAVE IN INTERVALLEY TRANSFERRED ELECTRON DEVICES
Storozhenko I. P.
114-117
Role of electron scattering by nonuniform distribution of neutral impurity and alloy potential has been studied. It has been shown that increasing coordinate dependence of low-filed mobility in n+-n-n+ intervalley transferred electron devices can result to appearance and drift of dipole domains. Cause of these is stationary componentry of relaxation velocity such as decreasing of coordinate functions of neutral impurity concentration, alloy potential and binary components contents in ternary and quaternary semiconductors. Current oscillation efficiency increase and optimal work frequency decrease at optimum distribution of neutral impurity in active zone.
AVALANCHE-CASCADE AMPLIFICATION OF IMPULSE IN pn-i-pn STRUCTURE WITH REVERSE BIASED p-n JUNCTIONS
Lukin K. A., Maksymov P. P.
118-124
The avalanche-cascade amplification in the reversed bias pn-i-pn structures in the linear and nonlinear modes is designed. Influencing of charge of mobile carriers, concentrations of impurity atoms, electric field and reverse bias on amplification are explored. Resonance frequency of GaAs pn-i-pn structures is certain. Influence of lifetime of no equilibrium carrier of current on the size of threshold current of GaAs pn-i-pn structure is certain.
MAGNETIC RADIOSPECTROSCOPIC COMPLEX “KVARK” OF MILLIMETER WAVEBAND LENGHTS
Nedukh S. V.
125-129
Design features of magnetic radiospectroscopic complex “KVARK” and its operates opportunities are present. The preferences of radio-spectroscopic complex “KVARK”, applied to carry out investigations of magnetic micro- and nanostructures by magnetoresonance technique at frequency band 20-60 GHz, field band 0-1,9 T, temperature band 77-300 K are demonstrated. Experimental analysis of usage of same specialized resonator cells (tunable cavity, tunable open resonator, waveguide EHF field concentrator) embedded into electrodynamic modules of complex are given. It is shown, that module-based design of the complex allows to modify quickly it for measurement of non resonance effects of Giant Magnetic Resistance/Impedance and Tunnel Magnetic Resistance/Impedance as well. Experimental results of study of some prospective magnetic nanostructures proving the advantage of radiospectroscopic complex “KVARK” usage are presented.
ON THE IMAGE RECONSTRUCTION UNDER ITS FOURIER-TRANSFORM MODULUS
Kornienko Yu. V., Skuratovskiy S. I.
130-141
The iterative reconstruction procedure proposed before for the object of limited size was investigated by means of computer experiment. Good convergence to the correct result from some its neighborhood was confirmed, and the possibility of convergence to a wrong result (called ‘trap’), while a random initial approximation was selected, was shown. A discrete nature of such traps set was established. Fractal-like dependence was found of the process convergence limit on the initial approximation. Probability of correct image reconstruction under random initial approximation was estimated. The obtained results are illustrated with graphics, half-tone images and color maps.