AN ENGINEERING MODEL FOR CALCULATING SIGNAL LEVELS FOR TRANS-HORIZON TROPOSPHERIC PROPAGATION OF VHF AND MICROWAVE RANGES TAKING INTO ACCOUNT THE ELEVATION HEIGHTS OF THE EMITTING AND RECEIVING ANTENNAS
A.L. Khanis, S.V. Bespalko, V.A. Khanis, A.A. Khanis
The relevance of the article is due to the practical needs of calculating signal levels for over-horizon tropospheric propagation of radio waves in the absence of detailed data on the state of the troposphere and the earth’s surface. Currently, there are a number of numerical computer models for calculating signal levels in conditions of over-the-horizon propagation of radio waves, taking into account the elevation of the transmitting and receiving antennas, but they require a large amount of initial information in the form of detailed meteorological observations, forecasts of the state of the atmosphere, as well as data on the terrain and the state of the Earth’s surface, which are usually unavailable. The existing approximate engineering models that do not require detailed data about the conditions of radio wave propagation are developed in relation to the location of the transmitting and receiving antennas on the Earth’s surface. The model proposed in this paper is based on the introduction of an average attenuation multiplier for standard conditions in the troposphere, transmitting and receiving antennas placed on flight-lifting vehicles and splitting the propagation route into sections of line of sight and over-horizon propagation. The purpose of the study is to develop and describe a model for calculating signal levels (attenuation multiplier) in the conditions of over-horizon tropospheric propagation of radio waves, in relation to the case of placement of radiating and receiving antennas on flight-lifting vehicles. The tasks that are solved to achieve this goal consist in analyzing the radio wave propagation path and estimating the attenuation factor on the route as a sum of factors that characterize losses on sections of the route of various types – line of sight, diffraction zone and far tropospheric propagation. The method for estimating the attenuation factor on the track is to use a well-known engineering method for standard conditions of long-range tropospheric propagation as the base model for calculating the coefficient. The result of this work is a mathematical expression for engineering calculation of signal levels for over-horizon tropospheric propagation of radio waves, taking into account the elevation of the radiating and receiving antennas. The proposed model is based on the introduction of an average attenuation multiplier for standard conditions in the troposphere, transmitting and receiving antennas placed on flight-lifting facilities and splitting the propagation route into sections of line of sight and over-horizon propagation.it can be used for approximate estimation of the received signal levels during over-horizon tropospheric propagation of radio waves without detailed data on the state of the troposphere and the Earth’s surface.
Keywords:radio wave attenuation factor, horizontal tropospheric propagation of radio waves, calculation of signal levels on the propagation paths of radio waves, transmitting antenna, receiving antenna, flight-lifting equipment, refraction, diffraction, line of sight
THE TECHNIQUE OF CALCULATION THE PARAMETERS OF THE ELECTROMAGNETIC THE FIELDS SCATTERED BY THE BODY WITH COMPLEX FORM IN THE NEAR ZONE
The paper is based on the methodology that uses the representation of an object of complex shape as a set of facets, we investigate the characteristics of scattered by this object in its near zone. It is shown how, using the calculated data to explore the effect of the spatial configuration of the field on the accuracy of measurement of angular coordinates of the object. The calculated dependence of the relative field amplitude of the object and the plate from the corner for the near zone to the far zone. The graphical analysis of the dependencies shows that in addition to monotonic attenuation length fields exist oscillating damped oscillations. It is believed that the antenna is moved around the object at random are averaged over all viewing angles characteristics of the scattered field. After calculating the parameters of the distribution law of a random variable from section to section, we can conclude about how changing the process in time. The analysis demonstrates that when we move from the far zone to the near, there is a shift of peak values of amplitudes and is an extension of the main lobe of the secondary radiation. The histograms of the distributions of amplitudes and phases of a complex object, after analysis it was found that the distribution of instantaneous values of the amplitudes of the scattered field by the object is described by Rayleigh. If we consider the distribution of the instantaneous phase of the scattered field, the shape of the histogram is close in form to the histogram of a uniform law. The analysis of the results allows to assert that the regularities of the distribution of values of amplitudes and phases of the scattered field related to the far and near zones will be the same.
Keywords: complex object, electromagnetic wave, near zone, scattering, diffraction.
THE MODELING OF THE SCATTERING OF RADIO WAVES OF CELLULAR COMMUNICATION SYSTEMS ON THE ELEMENTS OF BUILDINGS
A.A. Alimbekov, E.A. Avdeenko, V.V. Shevelev
This paper considers the problem of scattering of electromagnetic waves in cellular communication systems, elements of buildings. As a basic method is proposed to use the radial approach. The main steps of the algorithm for the calculation of total attenuation of the signal caused by the diffraction at the corners of buildings. The loss caused by reflection of the radio signal from the earth, are calculated based on the Fresnel coefficients for a plane wave. Indicated input parameters for the calculation. A diagram of the module of calculation of fields scattered by buildings, which uses a block optimization. A classification of optimization techniques used in the optimization of communication systems. Methods associated with unconditional optimization are divided into: one-dimensional case multidimensional case. Optimization methods are divided into these: optimization under linear constraints, optimization under nonlinear constraints.
Keywords: diffraction, building, link, beam, electromagnetic wave scattering.
THE RESEARCH OF FEATURES OF DIFFRACTION PROCESSES IN THE HIGH FREQUENCY RANGE
V.G. Panarin, A.G.Yurochkin
This paper discusses the features of processes of diffraction of electromagnetic waves in the high frequency range as it is promising from the point of view of further development of communication systems. It is noted that with the increase in frequency is required to consider the objects surface on which the diffraction as rough. The numerical simulation is introduced the Fresnel’s coefficient of roughness. This description of the reflection coefficients taking into account the surface roughness. Given the calculated reflection coefficients for different polarizations of the incident electromagnetic wave depending on frequency. The dependence of the reflection coefficient depending on angle of incidence for a given frequency of the incident electromagnetic wave.
Keywords: diffraction, electromagnetic waves, reflection coefficient, Fresnel’s coefficient.
THE ANALYSIS OF ELECTROMAGNETIC WAVE PROPAGATION INSIDE THE BUILDING WITHIN THE RADIAL APPROACH
A. P. Preobrazhensky
In this paper the analysis of the characteristics of radiation methods for the analysis of electromagnetic wave propagation – the method of geometrical optics, physical optics, physical theory of diffraction are considered. In order to determine the amplitude of the field in each point of space is required to determine all the rays that pass through this point. The considered model of distribution of the main beam in the room for two cases – floor reflections and the reflection from the object, located a certain height above the floor. Built according to the horizontal distance to the point of reflection of the beam on the incidence angle, the height of the receiver from the angle of reflection, the height of the receiver for various values of height of the reflecting object.
Keywords: simulation, communication, diffraction, wave propagation in indoor radiation methods.
THE SIMULATION OF SCATTERING CHARACTERISTICS OF OBJECTS HAVING EDGES
A. P. Preobrazhensky
In the paper the problems of scattering of radio waves on the objects, which include edge are considered. First, the analysis of the simplest edges, which is a wedge-shaped structure having a certain angle of solution is given. For the general case the edge of such structures may be truncated. The calculations of the scattering parameters was based on the method of integral equations in the framework of the Kirchhoff approximation. The examples of calculations of scattering characteristics are given, and built the radio image. Further the models of hollow structures is considered. The edges of these hollow structures can be defined by different edges. The calculations of the scattering parameters was based on the method of integral equations. The examples of calculations of scattering characteristics of hollow structures, and built the radio image of the edge part of the hollow structure.
Keywords: simulation, communication, diffraction, wave propagation, design, edge, hollow structure.
THE POSSIBILITY OF USING ITERATIVE METHOD FOR THE CALCULATIONS OF SCATTERING CHARACTERISTICS OF COMBINED OBJECTS
A. G. Yurochkin, A.V.Danilova, I.A.Gusarova
This paper considers the scattering of radio waves on the combined object consisting of several components. One of the possible ways, which is analyzed by the application of the method of integral equations. But with a large size of circuits and an increase in the number of components the time required for calculations increases significantly. In this regard, the iterative method is considered, which takes into account only the currents that are related directly to the reflection between components, which leads to a reduction in the size of the matrix of linear equations and an overall reduction in the computation time. Given an example, when as a combined object is a combination of two-dimensional elliptic cylinders. Characteristic size at which the iterative method works well.
Keywords: communication, diffraction, wave propagation, method of integral equations, iteration, cylinder.
THE ANALYSIS OF APPROXIMATE MODELS FOR ESTIMATING THE AVERAGE CHARACTERISTICS OF THE SCATTERING DIFFRACTIVE STRUCTURE
A. G. Yurochkin, A.V.Danilova, I.A.Gusarova
This paper analyses the possibilities of how to apply the approximate model in order to assess the average characteristics of the scattering object. The exact approach is based on the method of integral equations, and an approximate model based on the combination of the method of edge waves and the physical optics approximation. The object is represented in the form of separate components. It is shown how the defined sector angles, given the framework of specific errors. Based on how aggregated information on the elements of an object given suggestions on how to build a subsystem of CAD in order to design the average characteristics of the objects. As a test data for the subsystem are selected dimensions of the elements and sector angles, the required levels for the average characteristics of the scattering.
Keywords: communication, diffraction, wave propagation, design, CAD, diffraction structure.
THE CHARACTERISTICS OF TWO-DIMENSIONAL PERIODIC COMBS WITH DIELECTRIC WAVEGUIDE
A. A. Maximova
The paper discusses the issues of diffraction of electromagnetic waves on reflective comb with double periodicity is covered by a dielectric layer. The algorithm, which is considered, based on the method of integral equations for the problem of determining the currents on the surface of the comb. The obtained result can be generalized to two-dimensional comb. According to the found current density distribution on the surface of the comb element can be determined of the scattered electromagnetic field.
Keywords: scattering of radio waves, diffraction, two-dimensional-periodic comb filters, dielectric waveguide.
MODELLING OF DISPERSION OF ELECTROMAGNETIC WAVES IN AN INHOMOGENEOUS MAGNETO-DIELECTRIC BODIES
In this paper, the analysis in the time domain based integral equation approach. The approach is considered for describing of transient processes in composite metal-dielectric bodies is given. Numerical examples are given to demonstrate the stability and precision of the proposed method. As the object of analysis is a metal cylinder.
Keywords: modeling, scattering on magneto-dielectric body, diffraction.