THE PREDICTING OF SCATTERING CHARACTERISTICS FOR METAL OBJECTS WITH ABSORBING COMPONENTS IN THE FREQUENCY RANGE
A. A. Zhilina, V. N. Kostrova
The research urgency is caused by the fact that in the modern dynamic systems modeling and design, researchers do not always have information about its functioning in a given frequency range. This article discusses the technique of prediction of radar characteristics (RС), metal objects containing absorbing components in a certain frequency range, using the information on the scattering properties of the components of these objects. A leading approach to the study of this problem is the use of the apparatus of the green’s function. Scattered electromagnetic field is calculated on the basis of the method of integral equations. When accounting for the absorbing components used impedance boundary conditions. Examples are given of prediction RС in the case where the object falls E-polarized plane electromagnetic wave. Was carried out approximation of the scattering parameters in a given sector of angles based on algebraic polynomial, given the coefficients of the polynomial. The algorithm was developed for the synthesis of the size of the object based on the data predict the levels of electromagnetic waves. Given the dependence of the prediction error values of the electromagnetic field of the frequency bands. The materials of the article are of practical value to professionals associated with the development of complex electrodynamic structures.
Keywords: scattering of electromagnetic waves, predicting, acquisition, frequency analysis, synthesis.
THE MODELING OF THE DETECTION OF WEAPONS ON THE HUMAN BODY BY PULSED IRRADIATION
D.A. Serdyutskaya, A.A.Maximova
The possibilities of detection and identification of metal items and especially weapons, with the size of the order of one to two decimeters, which are hidden on human body, based on the use of phased array antenna, which includes ultra-wideband transceivers are considered. Through the use of UWB-signals the excitation of oscillations at the resonant frequencies, and especially at the main resonance, that defines a clear object selection. Broadband irradiation object of microwave signal in the corresponding frequency range is several hundred MHz, leads to the occurrence of low-frequency resonances and delay response for the receiver when using phased arrays for imaging radio images. Further processing of the reflected signal includes the classification of a hidden object based on the respective resonance frequencies, which allows to distinguish the guns and knives from useful items such as mobile phones and cameras.
Keywords: impulse, scattering of electromagnetic waves, safety, identification of objects.
MODELING OF SCATTERING OF ELECTROMAGNETIC WAVES ON THE ELECTROMAGNETIC OBJECTS USING THE MODIFIED METHOD OF MOMENTS
In the paper the approach is discussed to the solution of problems related to scattering of electromagnetic waves on objects of large dimensions based on the combination of surface integral equations and the method of moments. We apply basic and trial functions in the method of moments in the process of information integral equations to a system of linear equations for the case when the matrix of impedances is very full. The wavelet transform is used in order to simplify the matrix. A comparison of results obtained based on this approach and other methods achieved their satisfactory coincidence is carried out.
Keywords: integral equations, method of moments, wavelet transform, scattering of electromagnetic waves.
A HYBRID METHOD FOR CALCULATION OF SCATTERING CHARACTERISTICS OF OBJECTS ABOVE A ROUGH SURFACE
An iterative hybrid method is considered combining the Kirchhoff approximation and the multilevel fast multipole algorithm (MLFMA) is studied for electromagnetic scattering from three-dimensional (3-D) object above a two-dimensional (2-D) random dielectric rough surface. In order to reduce computational costs, some types of speed calculations were used. First, it is used to speed up calculations of electromagnetic field in far field approximation (FAFFA) of the process of interaction between the rough surface and the object. Secondly, based on the mechanism of scattering on a rough surface, and derived a rule for moderately rough surface bistatic scattering, which can further increase the speed of iteration. Compared with traditional methods, a hybrid the method of procedure is sufficient for analysis scattering of 3-D object above random rough surfaces.
Keywords: scattering of electromagnetic waves, method, hybrid method, modelling,
FORECASTING OF THE CHARACTERISTICS IN THE PROBLEM OF SCATTERING OF ELECTROMAGNETIC WAVES ON THE OBJECT
The paper is devoted to forecasting of the characteristics of the problems connected with the scattering of electromagnetic waves. For the simplest object cylinder the regularities of changes of elements of the Green function for different values of the radius of the cylinder was demonstrated
Keywords: scattering of electromagnetic waves, forecasting, Green function.
THE PROBLEMS OF OPTIMIZATION OF DIFFRACTION CHARACTERISTICS OF TECHNICAL OBJECTS
The analysis using the swarm of bees in the analysis of diffraction characteristics of technical objects is carried out.
Keywords: optimization, diffraction, scattering of electromagnetic waves.
THE PROBLEMS OF ESTIMATION THE AVERAGE SCATTERING CHARACTERISTICS OF ELECTROMAGNETIC WAVES
In this paper we consider some problems that arise in the evaluation of secondary scattering characteristics of electromagnetic waves. The basic methods for the estimation of the scattering parameters are pointed out. The structure of the subsystem for the design of objects with given average characteristics of the scattering is given.
Keywords: : scattering of electromagnetic waves, design, method, object.