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A technique for calculation of currents in transmission lines in a wide frequency range is proposed. The technique is based on a generalization of the lumped-circuit calculation methods to the case of long transmission lines by the introduction of refinement functions. A worst-case model for the amplitude-frequency characteristics of currents in the transmission line is developed on the basis of the proposed technique. The model is intended for diagnostics (express analysis) of electromagnetic compatibility in complexes of radio and electronic equipment. Worst-case nature of the model is provided by construction of the envelope of the current's maxima (observed at resonances) for the high-frequency band. The validity of the model is checked by comparison with the results of numerical simulation of single wire above ground plane, twowire, coaxial, and triaxial transmission lines in a wide range of parameter values: the frequency is varied from 10 kHz to 8 GHz, the length of the line is from 20 cm to 5 m, height of the line above the ground surface is from 2 mm to 100 mm, the ratio of the load capacitance (inductance) to the line capacitance (inductance) is from 10−40 to 104. Straight and piecewise-straight lines (both parallel and non-parallel to the ground plane) are considered during the validation.

The analytical model for radiation of a rectilinear uniform transmission line placed above a conducting screen is proposed. The model is intended for diagnostics (express analysis) of unintentional interference in large complexes of radio and electronic equipment. The model makes it possible to compute the envelopes of the amplitude-frequency characteristics for electric and magnetic fields in any spatial point above the screen. Single wire above ground plane, coaxial and triaxial lines with various grounding configurations are considered. The model is based on replacement of the complicated transmission line by an equivalent (in terms of the radiated field) single wire over ground plane. Correctness of the proposed model was verified by comparison with numerical simulation results in the frequency band from 10 kHz to 2 GHz for lines of length from 5 cm to 10 m with various load and source impedances, the line height above the ground plane was varied from the radius of the line to 5 m, the observation point position was up to 5 m away from the center of the line in arbitrary direction.

A worst-case model of the plane wave diffraction by the rectangular or circular aperture is proposed. The model is intended for EMC analysis in a frequency range from 1 Hz to 40 GHz, and it is based on combining the analytic solutions of the diffraction problem for low-frequency, resonance, and high-frequency ranges. The combining is carried out by the use of matching functions which define a contribution of each analytic solution. The correctness of the proposed model was checked by comparison with numerical solutions of the diffraction problem in a wide range of the parameters' values: ratio of the wavelength to the maximal dimension (diagonal or diameter) of the aperture is from 0.05 to 300; ratio of rectangular aperture sides is from 1 to 100; ratio of the distance (from the aperture center to the observation point located behind the screen at arbitrary position) to the maximal dimension of the aperture is from 0 to 1000.

The worst-case model of a wire radiation field intended for the analysis of spurious couplings in complexes of radio and electronic equipment has been developed. The model is based on dividing the wire into straight-line segments and considering forward and backward current waves in each segment. The solution for each current wave is interpreted as interference of fields radiated by equivalent point sources, and the envelope of the amplitude-frequency characteristic is found in the area of resonances. The correctness of the model is checked in a wide range of problem parameters values: the length of the wire ranges from 0.1 m to 10 m, the height of the wire above the ground plane ranges from 0.1 mm to 1 m, and the observation point position is up to 10 m away from the center of the wire in arbitrary direction.

Electromagnetic properties of radio absorbing coating which structure includes periodic gratings made from conducting wire elements are investigated. It is established that the use of periodic gratings allows improving of radio absorbing properties of known types of materials with electric nature of absorption.

Influence of distribution of particles upon radio-absorbing properties of composite materials was investigated. It was established, that fractal clusterization leads to essential magnification of an imaginary part of effective permittivity in comparison with materials, in which fibers are distributed periodically or under the uniform casual law.

A possibility is discussed of developing a microwave probe with a modulated scattered cross-section in the form of a vibrator with a photo-controlled load and a photosensitive semiconductor dipole

Presented in this paper are the results of numerical research of electromagnetic properties of pyramidal type radio-absorbers. Influence of modification of constructive and material absorber's parameters on their electromagnetic properties is investigated

The technique for calculation of electromagnetic properties of composites was presented. It is based on the hierarchical decomposition and the method of minimal autonomous blocks

Electrodynamic methods of analyzing the parameters of broadband electromagnetic wave absorbers are considered. The results of physical and computing experiments for the development of electromagnetic wave absorbers for anechoic chamber equipment are presented.

This paper presents a technique for the study of electrodynamics properties of complex media, composites and arrays that have a periodical structure. This technique is based on the minimal autonomous blocks (MAB) method and the theory of periodical structures. In accordance with Floquet's theorem, the problem of scattering of the plane electromagnetic wave from an array of one- or two-dimensional objects may be transformed to determine propagating Floquet's harmonics of the scattering field in the space wave guide.

The results of theoretical and experimental examination of the electrodynamic performances of composite materials are given. A technique of calculation of electrodynamic parameters of materials with composite interior structure and examples of its practical usage are described. The results of an experimental investigation of the interaction of microwave radiation with thin layers of oxides of copper and iron are presented. X-ray and electron diffraction examination of film ferromagnetic materials after microwave action has shown, that their parameters are essentially distinct from the parameters of materials obtained with standard technologies at similar temperatures and energies. The obtained results indicate the possibility of using microwave radiation in chemical technological processes. An effect is described in which total absorption of electromagnetic energy takes place at the expense of a passing chemical reaction. This opens perspectives of making a new class of radioabsorption materials.

The basic stages of the technique of calculation of effective electromagnetic parameters of composite materials and nonuniform media are presented. The technique is based on the method of minimum autonomous blocks. An example of usage of this technique for the calculation of effective parameters of a composite containing segments of conductive fibrils is given. We consider the interaction of a plane linearly polarized EM wave with a flat stratum of a composite.