ELECTROMAGNETIC MODEL AND CHARACTERISTICS OF POLARIZERS BASED ON SECTIONS OF SQUARE WAVEGUIDE WITH DIAGONALLY PLACED SQUARE RIDGES
L. A. Rud, K. S. Shpachenko
Using the mode-matching and generalized scattering matrix techniques a full-wave electromagnetic model of waveguide polarizer is developed. It transforms the dominant mode of input rectangular waveguide into elliptically polarized mode of output square waveguide. The phase shifting section is realized on the base of one or two segments of a square waveguide having two diagonally placed square ridges. The optimization of narrow- and broadband polarizers has been carried out. It is found out that the polarizers with one-segment phase shifting section can provide the bandwidth from 12 to 15 % at the level of axial ratio r < 3 dB and VSWR < 1.2 whereas the two-segment ones have the bandwidths more than 20 % at r < 1 dB and VSWR < 1.15.
ELECTROMAGNETIC FIELD AT FAR AND NEAR ZONE DUE TO WAVE DIFFRACTION BY STRIP STRUCTURES
S. N. Vorobyov
The near and far diffracted field and its Fourier-amplitude are studied numerically for three structures of metal strips, namely, one, two and finite number of plane strips. The accordance between the field Fourier-amplitude and the amplitude and phase of scattered field by diffraction of H-polarized plane wave is elucidated. Physical features of scattered field are discussed.
ABOUT DISCREPANCY BETWEEN DATA OF SUBSURFACE SOUNDING AND THEORETICAL MODELS OF SOIL DIELECTRIC PROPERTIES
V. G. Sugak, I. S. Bondarenko, A. V. Sugak
Results of comparison of theoretical models of dielectrical properties of soils with data obtained directly from subsurface radar sounding are considered in the paper. It is shown that the frequency dispersion of attenuation factor is less and frequency dispersion of radio wave propagation velocity is more than it is described in theoretical models. A possible physical mechanism of these phenomena is proposed to be concerned with influence of surrounding soil pressure on soil particles and soil pores.
RADAR SOUNDING OF SMALLSCALE TURBULENCE IN BOUNDARY LAYER OF ATMOSPHERE
Ye. N. Belov, O. A. Voitovych, G. A. Rudnev, T. O. Tkachova, G. I. Khlopov, S. I. Khomenko
The data of experimental study of radar reflectivity of optical unobserved objects, obtained by incoherent sounding in wavelengths 8 mm and 3 cm are analyzed. The altitude profiles of structure constant and its season variations are given as well as existing of turbulence irregularities in spatial spectrum on the order of 4 mm are experimentally confirmed.
FREQUENCY DEPENDENCE OF MILLIMETER AND SUBMILLIMETER WAVE ATTENUATION COEFFICIENT IN RAINS AT ACCOUNTING OF SMALL DROPLETS IN RAIN DROP SIZE DISTRIBUTION FUNCTION
Yu. I. Malyshenko, A. N. Roenko
It is shown that most of probability density distributions of rain drop sizes, widely used in calculations of rain attenuation statistics for microwave radar and communication systems, describe the real quantity of the rain small droplets rather inaccurately. New more adequate distribution function, which takes into account small droplets, is proposed. Taking into account the new distribution the radiation attenuation in rains of different intensity is calculated.
USING OF RADAR AND GEOSTATIONARY SATELLITES SIGNALS FOR DETERMINATION OF HYDROMETEORS WATER CONTENT
I. M. Mytsenko, D. D. Khalameyda
A complex method for hydrometeors water content detecting is studied. The method uses data of size and location of hydrometeors given by radar and signal attenuation obtained by proposed apparatus which receives signals of a geostationary satellite. Theoretical grounds of the method and experimental results are presented. The method is effective for determination of water content of hazardous cumulonimbus clouds and powerful torrential rain clouds.
E. I. Yatsevich, A. P. Nickolaenko
The work is devoted to the evaluation of ELF field disturbance by trees and bush. By simulation dependences of the sizes of the zone of influence of plants on the received signal on plant size were obtained. Results derived may be useful for selecting the deposition receiving ELF antenna.
DOUBLE FREQUENCY SENSING OF LIQUID PRECIPITATION BY WEATHER RADAR MRL-1
Ye. N. Belov, O. A. Voitovych, A. M. Linkova, G. A. Rudnev, G. I. Khlopov, S. I. Khomenko
Results of experimental study of double frequency sensing of microstructure parameters of liquid precipitation on the base of on earlier developed algorithm and by means of weather radar of type MRL-1 are described. The used algorithm provides single-valued reconstruction of microstructure parameters and allows to take into account signal attenuation in the rain. Obtained radar results are compared with data of fast-acting ground rain gage. Main calculating relations, parameters of experimental equipments and results of preliminary experiments are presented.
OBLIQUE SURFACE JOSEPHSON PLASMA WAVES IN LAYERED SUPERCONDUCTORS
Yu. O. Averkov
In this paper the theoretical analysis of oblique surface Josephson plasma waves (oblique SJPWs) that propagate along an interface between a dielectric and layered superconductor is first presented. The case where the superconductor layers are perpendicular to the interface is considered. The oblique SJPWs are the surface electromagnetic waves propagating in the interface plane at an arbitrary angle with respect to the superconductor layers. The electromagnetic field of the waves is the superposition of ordinary and extraordinary surface electromagnetic waves. The dispersion equation of the oblique SJPWs has been derived. This equation is the most general dispersion equation of the SJPWs in the case under study. The problem of excitation of oblique SJPWs by means of the attenuated total reflection method is solved. It has been established that the process of the excitation of oblique SJPWs is accompanied by onset of an additional reflected wave in the prism with a polarization orthogonal to the polarization of the incident wave. It has been found that the reflection coefficient of the exciting wave in the prism can vanish for some optimal parameters of the structure.
V. V. Filippov, V. L. Berezhnyj, D. L. Grekov
The paper deals with the method for measuring the average of plasma electron density in stellarators Uragan-2M and Uragan-3M. The first measurements of plasma electron density in on line regime are presented. The new method of probing signals phase shift determination is developed both theoretically and experimentally.
THE DECISION STATISTICS OF ENERGY DETECTION BASED ON TWO-PARAMETRICAL EXPANSION OF STOCHASTIC SIGNALS
A. A. Mogyla
Questions of optimal detection of stochastic signals hiding with known spectral-temporal structure on the background of normal noise with a flat spectrum in a receiver pass-band are considered. The likelihood ratio and the decision statistics are obtained using two-parametrical transform; the block diagram of detector is developed. The approximate expressions for conditional probability density of amplitude are found for two cases: only Gaussian interference affects on an input; both a signal and interference affect on an input.
ECCENTRIC CYLINDRICAL DIODE WITH CURRENT LIMITED BY SPACE CHARGE
G. A. Alexeev, L. V. Stulova
The paper deals with the theoretical analysis of the influence of the emitter arrangement asymmetry upon angular dependence of anode current density in cylindrical diode.
K. A. Lukin, P. P. Maksymov
The power characteristics of multifrequency generators of millimeter and sub-millimeter waves on the basis of Si and GaAs pn–i–pn-structures with abrupt p–n-junctions and permanent reversed bias are explored. As a mathematical model of generators equations of diffusive-drifting model of semiconductors are used. The algorithm of decision of difference equations of diffusive-drifting model is given. Volt-Ampere characteristic of Si pn–i–pn-structures is studied. The dynamics of distributing of the electric field, electric potential and total charge of mobile carriers and admixtures atoms in pn–i–pn-structure are explored. Fourier spectrum of density of useful power and electronic efficiency of multifrequency generators is calculated.