2000, volume 5, ¹ 3
AXIALLY ROTATED STEP JUNCTIONS OF RECTANGULAR WAVEGUIDES AND RESONANT DIAPHRAGMS ON THEIR BASIS
L. A. Rud
7-13
The exact numerical algorithm for a calculation of the full-wave S-matrix of a step junction of rectangular waveguides with a possibility of turning one of them around its axes is developed by the mode-matching method. Such a junction is used for building the algorithm for the analysis of inclined resonant diaphragms of a finite thickness in a rectangular waveguide. It is shown that an opportunity of controlling the diaphragm quality factor due to changing the rotation angle is increased sufficiently if the diaphragm slot is filled by a dielectric.
ON THE FEEDBACK IN THE SMITH-PURCELL EXPERIMENTS
B. K. Skrynnik, V. K. Korneenkov, M. Yu. Demchenko
14-18
Radiation of fast (space) waves ranging 0.9 to 3.6 mm and at angles close to 90 degrees from an electron flow not modulated by an external signal has been experimentally detected. The above experiments were similar to those of the Smith-Purcell, but in the case of the millimeter wavelength range and accelerating voltage from 2.5 to 5.2 kV.
The minus first space harmonic of a slow (surface) wave of the periodic structure excited in the wavelength range from 11 to 0.5 mm in the BWT regime has been used for the self-modulation of the electron flow.
The analysis of the known conditions related to the radiation of fast and slow waves, modulation of an electron flow by a surface wave, both spatial and time retardation of the higher-order harmonics of an electron flow has been made. The results have been verified experimentally.
It is found that a principally unavoidable positive feedback via a slow wave of a plane grating has been used for obtaining the electron flow modulation in the Smith-Purcell experiments, that is similar to the given experiments.
AN OPEN RESONATOR WITH RECTANGULAR GROOVE ON THE REFLECTOR, THEORY AND EXPERIMENT
M. Yu. Demchenko, V. K. Korneenkov, V. S. Miroshnichenko, A. E. Poyedinchuk, Yu. V. Svischov,
Yu. A. Tuchkin
19-28
An open resonator with a rectangular groove on a plane reflector as a model of an open resonant system of the diffraction radiation oscillator is considered. For E-polarised wave incident on the groove, the resonant distances, diffractional Q-factor and field distribution of the excited modes have been analysed and examined. The theoretical computations are in a good agreement with the experimental results.
Optimization of a conversion of waves on the cascade of thin diaphragms in a round waveguide
V. V. Shcherbak
29-35
The resonance conditions of an conversion of waves on cascades of multistrip axisymmetrical diaphragms in round waveguides are investigated. The multiparametric optimization is conducted to reach a "pure" conversion of the basic mode in one of the higher wave modes. The used efficient algorithms are supplemented by the regularizations which are necessary in case of the narrow elements of diaphragms.
ON CHARACTERISTICS OF A PLANE METAL-DIELECTRIC WAVEGUIDE AT THE CRITICAL POINTS OF THE FREQUENCY SPECTRUM
A. D. Barkov
36-43
The
characteristics of the field resulting from the excitation of a plane-parallel
wavequide by an eigen mode are studied. The wavequide has an ifinite lower wall
and is loaded by a dielectric layer infinite in both directions. The case is
considered when the frequency parameter equals to the critical value. For these
values, simple expressions for the factorization function are obtained, and the
- dependence of the field
characteristics on the relative permittivity in the whole
range of its variation has been analysed.
EXPERIMENTALLY STADY OF SPHERICAL REFLEKTOR ANTENNA IN MILLIMETER WAUE BAND
S. P. Martynyuk, G. I. Khlopov
44-46
The spherical reflector antenna is experimentally studied. Antenna is based on the phase-compensated feed with dielectrical lens for decreasing of the aberration’s influence. It was shown that such method is quite effective for the aperture antennas with spherical reflectors and permits wide angle scanning in the millimeter wave band.
Scalar HORN ANTENNA OF millimeter waue BAND
S. P. Martynyuk, G. I. Khlopov
47-49
The scalar horn antenna of millimeter wave band is developed. The radiation characteristics of scalar horn are described and results of using in two-mirror antenna with spherical reflector are discussion.
RADIATION CHARACTERISTICS OF A SLOT ANTENNA LOCATED ON A SEMI-SPHERICAL PROTUBERANCE ON THE PERFECTLY CONDUCTING SCREEN
Yu. M. Penkin, P. I. Klimovich
50-54
Radiation fields of a circular slot located on a semi-spherical protuberance on the screen have been determined by using the Green’s functions for the axial-symmetric excitation. Here, the protuberance and the infinite screen have been assumed as perfectly conducting. The values of radiation conductivity and directivity of the slot antenna have been numerically studied under changes of antenna’s geometrical parameters.
EXPERIMENTAL STUDY OF SPECTRA OF A RAIN-DRIVEN WATER SURFACE AND RADAR BACKSCATTERING FROM IT AT X- AND Ka-BAND
V. B. Razskazovsky, Yu. F. Logvinov, Yu. A. Pedenko
55-64
This paper presents the results of experimental studies of spectra of a water surface splashed by falling single drops, artificial rain and small air bulbs as they come at the surface and burst. The main attention is given to the components of the surface ruffles that have a pronounced effect on back-scattering of microwave and millimeter waves at low grazing angles. The results of calculation of the radar back-scattering intensity obtained by using the found forms of space-domain spectra have been compared with the results of scatterometer observations in the X- and Ka-bands.
INSTABILITY OF SURFACE PLASMONS CAUSED BY A CHARGED PARTICLE FLOW IN A MEDIUM WITH THE INHOMOGENEOUS POTENTIAL
V. M. Yakovenko, I. V. Yakovenko
65-68
A theory of interaction of charged particle flows crossing the media interface with surface plasmons is built with an account of an inhomogeneous potential. The kinetic equation for the surface plasmons and conditions of their instability are formulated. Dependence of the increment on the height of a potential barrier is obtained.
EFFECT OF TRANSLATIONAL SYMMETRY ON ELECTROMAGNETIC PROPERTIES OF A SEMICONDUCTOR-DIELECTRIC STRUCTURE IN A MAGNETIC FIELD
A. A. Bulgakov, V. K. Kononenko
69-78
A zonal spectrum of natural modes of a periodic structure formed by alterating layers of dielectric and semiconductor is studies. The modes are assumed to propagate at an angle with respect to magnetic field and experience a delay. A method of derivation of a dispersion equation is presented, and its properties are analyzed. Two independent spectra of natural modes are found in the considered structure in the absence of losses. Field distributions of these modes in the layers are determined and their domains of existence are classified. It is revealed that the transmission bands of these spectra may develop.
STOCHASTIC PROPERTIES OF THE BILLIARD-TYPE THREE-DIMENSIONAL ELECTROMAGNETIC MICROWAVE SYSTEMS
E. M. Ganapolskii, Z. E. Eremenko
79-84
Stochastic spectra of the three-dimensional electromagnetic quasi-optical systems which are similar to the Sinai scattering billiards (S-system) and Bunimovich billiards (B-system) have been experimentally studied for the millimeter radiowave range in the interval 34-38 GHz. It is found that the effects peculiar to the systems with quantum chaos such as the frequency repulsion effect, closeness of the inter-frequency interval distribution to the Wigner one can be observed in these spectra. However, they differ from similar systems in spectral rigidity and correlation properties of these intervals. It is also found that a mechanism of the wave propagation instability in the Bunimovich billiards caused by the defocusing of waves leads to stochasticity, which is similar to the spectrum stochasticity in the Sinai scattering billiards. Also, the effect of the Kolmogorov-Sinai system entropy quantity on spectrum stochasticity has been observed.
STOCHASTIC PROPERTIES OF A CAVITY RESONATOR FILLED WITH RANDOMLY LOCATED SAPPHIRE PARTICLES
E. M. Ganapolskii, Z. E. Eremenko
85-90
The properties of a spectrum of eigen oscillations of a quasi-optical microwave resonator filled with randomly located sapphire particles have been experimentally studied in the eight-millimeter frequency band at the frequencies from 26 GHz to 38 GHz. The particles may be of regular shape (as a cube) or irregular with characteristic sizes comparable to the wavelength in the material. It has been found that such a resonator has a stochastic spectrum, in which the properties characterizing the quantum chaos are exhibited: effect of "repulsion of levels", distribution of inter-frequency intervals is close to Wigner distribution, the curve of spectral rigidity is also close to the relevant curve of a Gaussian orthogonal ensemble. The action on the resonator of a short electromagnetic pulse with microwave filling has been studied. It has been found that the resonator has an ability to retain the energy of a microwave pulse in a rather wide (more than 10%) frequency band for rather a long time. The explanation of this effect has been proposed.
INTERACTION OF ELECTRON BEAMS WITH ELECTROSTATIC OSCILLATIONS IN CYLINDRICAL SOLID STATE STRUCTURES
A. F. Rusanov, V. M. Yakovenko
91-96
The paper presents a theoretical study of electrostatic oscillations in a cylindrical system which represents an electron beam surrounded by a finite-size semiconductor which borders dielectric or metal. It is shown that, if we take into account the finite size of a semiconductor, the region where the space charge waves are unstable is divided into regions of stable and unstable states.
HOLE-ELECTRON PROCESSES INTO ANTI-CLOSED m-n CONTACT
N. A. Shekhovtsov, A. N. Shekhovtsov
97-103
The energy conditions for dynamic wide m-n contact determined. The equation for volt-ampere characteristics of m-n contact and m-n diode is obtained. The dependence of differential capacity of m-n contact and m-n diode upon voltage is obtained. It is shown, that the capacity of m-n contact is changing the sign from positive to negative under the increasing of reverse voltage.
A QUASI-OPTICAL DIELECTRIC RESONATOR. MEASUREMENTS OF MICROWAVE CHARACTERISTICS OF DIELECTRICS AND CONDUCTORS
A. A. Barannik, Yu. V. Prokopenko, Yu. F. Filippov, and N. T. Cherpak
104-109
The approaches
to studying the microwave characteristics of dielectrics and conductors with
the aid of quasi-optical dielectric resonators, in which the anisotropy axis of
a dielectric coincides with that of a resonator, have been developed. These
methods involve the solution of a set of equations based on a characteristic
relation with the experimentally measured values of eigen frequencies of a
resonator and identification of the observed types of oscillations. Besides,
these methods involve the use of the experimentally obtained values of Q-factor
of resonator in the derived power expressions. The examples of how the above
methods could be applied to determination of the permittivity tensor components
[ij] and
tan
of dielectric, and the surface
resistance Rs of the end conducting plates of cylindrical
resonators are given. The spectral and power characteristics of the
higher-order EHnms- and EHnms - type
oscillations with the radial indices of s = 1,2 have been analyzed. The
suggested methods are of interest for studying the properties of dielectrics
and measuring the values of surface resistance Rs of
conductors and superconductors in the millimeter wavelength range.
FREQUENCY MULTIPLYINON ON RESONANCE-TUNNELING DIODES IN MM-WAVE REGION
O. V. Botsula, V. V. Medvedev, E. D. Prokhorov
110-113
The frequency multiplying on resonance-tunnelling diodes with different voltage-current characteristics is considered. The single-level resonance-tunnelling diodes Al0.2Ga0.8As/GaAs, In0.53Ga0.47As/AlAs, InAs/AlAs/GaSb and two-level resonance-tunnelling diode AlAs/GaAs are considered. It is shown that the most coefficient of frequency transformation on all harmonicas with bias voltage and without bias voltage, possesses the two-level resonance-tunnelling diode in contrast with single-level resonance-tunnelling diodes. The high coefficient of frequency transformation on harmonicas allows to get the power on harmonicas comparable to power of generators on Gann diodes and avalanche-transit time diodes in millimetre-range.
MODIFIED VECTOR SIGMA-FILTER FOR MULTICHANNEL RADAR IMAGE PROCESSING AND INTERPRETATION RELIABILITY INCREASING
A. A. Zelensky, G. P. Kulemin, A. A. Kurekin, V. V. Lukin, O. V. Tsymbal
114-123
A novel vector filter called modified vector sigma-filter (MVSF) is proposed for processing the multichannel remote sensing radar images. It is demonstrated through a standard set of filtering quality criterions that the introduced modification provides a trade-off of vector sigma-filter basic properties. It possesses efficient suppression of multiplicative noise and good edge/detail preservation. Moreover, the MVSF simultaneously ensures an ability to remove spikes from images and excellent preservation of fine details even if they are characterized by rather low contrasts. For simulated images the increasing of reliability of bare soil erosion state estimation after application of the MVSF in respect to its componentwise counterpart and original noisy image is demonstrated.
RANGE AND VELOCITY VECTOR METER ON THE BASIS OF NOISE WAVEFORM AND RELAY TYPE CORRELATOR
A. A. Mogyla, K. A. Lukin, Yu. A. Shyian
124-130
The issue of both practical implementations of noise waveforms optimal reception and development of noise radar meters for both range and range rate vector has been considered. It has been shown that an output signal-to-noise ratio of relay type correlation receivers could degrade by 2 dB in comparison with that of the optimal receiver. The noise radar meters of both range and velocity vector have a high interference-immunity that allows to fulfil a single valued measurement with both high accuracy and resolution.
THE INTERRELATIONSHIP OF TWO-PARAMETRIC MODELS OF LIMITED ENERGY RANDOM SIGNALS IN DIFFERENT ORTHONORMAL BASISES
A. A. Mogyla
131-136
The interrelationship between two-parametric models of limited energy random signals in different orthonormal bases is obtained. The interrelationship is obtained between two-parametric models of their samples and the interrelationship of correlation function of component these signals on this framework too. To obtain these interrelationships, the mathematical apparatus of Hilbert spaces of random processes over Hilbert space of samples of Hilbert space their weighted selection is used. Energy characteristics of two-parametric models random signals in arbitrary orthonormal basises is introduced and the interrelationship between them is obtained.
QUASI-OPTICALBANDPASS AND BANDSTOP FILTERS BASED ON OPEN RESONATORS WITH A POLARIZATION GRATING
V. I. Bezborodov, V. K. Kiselyov, M. S. Yanovsky
137-142
Bandpass and bandstop filters for the shortwave part of the millimeter and for the submillimeter wavelength ranges are considered. These filters are based on open resonators equipped with parallel-located reflectors in the form of the polarization wire gratings. Main formulas for computing such filters are obtained by the polarization scattering matrix method. A possibility of using the above filters as the wave polarization converter, in particular, when it comes to resonant converting of the linear polarization into circular one, is shown.
AN ACTIVE CONVERTER BASED ON AN IMPATT DIODE IN THE SHORT-WAVE PART OF THE MILLIMETER WAVELENGTH RANGE
A. V. Zorenko, A. E. Koloshinsky, V. E. Chaika
143-147
Theoretical and experimental studies of an up converter in the 2-mm wavelength range based on Si DDR IMPATT diode have been carried out. The possibility of converting the frequency in the active regime with small losses and linear dependence of the output power on that of a low-frequency signal is demonstrated.
CONSTRUCTION OF NON REDUNDANT APERTURES OVER SQUARE GRIDS BY THE METHOD OF RANDOM SEARCH
Yu. V. Kornienko
148-154
A computer experiment was performed to construct non-redundant configurations with possibly maximal number of elements k on the square grid. Some results are obtained for the squares of dimention n from 5 to 20 grid nodes on the side. Dependence of k value achieved, on n value is shown on fig. 2, and configurations obtained, on fig. 3 - 9. A conclusion is drawn that in some cases random search can provide better results then known regular methods.