Vol 63, No 1 (2018)

For the action of a pulse field generated by industrial macrosources under the short-circuit condition used as an example, mathematical models, the circuit of an experimental setup, and design parameters for physical simulation of electromagnetic interferences in the communication lines of the electronic equipment have been proposed. The presented software provides the basis for a practical procedure for estimating the interference immunity of the electronic equipment subjected to the electromagnetic action of industrial macrosources.

Effect of argon pressure 0.09 ≤ P ≤ 1 Pa on the microcrystalline structure and magnetic properties of the cobalt films with a thickness of d ≈ 300 nm that are fabricated with the aid of magnetic sputtering on the SiO₂/Si substrates is studied. It is demonstrated that the films obtained at a pressure of Р ≥ 0.2 Pa exhibit mixed crystal phase with close-packed hexagonal (CPH) and face-centered cubic (FCC) lattice with the CPH–Co(002)/FCC–Co(111) texture and column microstructure over thickness. The films deposited at a pressure of Р ≈ 0.09 Pa are characterized by the dominant FCC crystal phase with the FCC–Со(200) texture and inhomogeneous microstructure over thickness: at the interface with the substrate in a layer with a thickness of d₁ ≈ 150 nm, the films exhibit quasi-homogeneous microstructure that is transformed into the granulated microstructure at d > d₁. The films deposited at a pressure of Р ≈ 0.09 Pa have the saturation magnetization that is higher by 30% and the coercive force and linewidth of ferromagnetic resonance that are several times less than those of the film obtained at a pressure of Р ≈ 1 Pa.

Microsecond high-voltage solid state switches based on metal–oxide–semiconductor field-effect transistors for application in pulse grid modulators of high-power microwave devices have been developed and investigated. Stable switching ranges of the switches based on unipolar and bipolar control circuits have been established. Combined switches with operating voltages of up to 10 kV and pulse currents of up to 12 A have been experimentally implemented.

The features of transmission spectra characterizing the layers of a shallow-layered semiconductor‒insulator medium are investigated under the action of a magnetic field. In this case, n- and p-type semiconductors are analyzed. It is demonstrated that, at H₀ ≠ 0, the frequency gap, i.e., the zone eliminating wave transmission through a structure, is formed in the spectrum. In the absence of absorption near the lower zone edge (resonance frequency), the system of alternating narrow transmission and nontransmission zones concentrating with an approach to the resonance frequency is established to appear in the spectrum. It is revealed that oscillations arising near the frequency gap are smoothed with allowance for absorption in the structure.

The problem of estimation of the speech phonetic quality using a short fragment of the voice signal is formulated. The Kullback–Leibler minimum information discrimination principle is used to propose a novel criterion and develop an algorithm. The dynamic properties of the algorithm are analyzed. The algorithm is employed in the analysis of the functional state of speaker using the voice signal. It is demonstrated that the needed duration of the voice signal is several minutes only.

Problems arising in the course of practical implementation of the principles and of radio polarimetry are considered. It is shown how to ensure “polarization coloration” of the radiation pattern. The influence of various interferences and the noise, which inevitably exist during information transmission, is considered. A simplified scheme of the “polarization key” is presented and the possibility of application of the space–time modulation of the radiated wave for information transmission to the required address is demonstrated.

A method of the amplitude–phase multicriteria synthesis of a Pareto-optimal antenna array is proposed. The method is based on representation of the initial antenna array synthesis problem in the form of successively solved partial problems (subproblems) with small dimensionality. Each subproblem is reduced to determination of Pareto-optimal parameters of the amplitude–phase distribution of an additional beam added to the initial radiation pattern.

The realizability of polarization selection of electromagnetic waves is proved. The possibility of determination of the polarization of the radiated wave even in the case an arbitrary variation in the mutual positions of transmitting and receiving antennas is shown.

An approximate method is proposed for the solution of the vector problem of diffraction by a body of revolution. The material characteristics of the body are independent of the angular coordinate in the cylinder coordinate frame. The method is tested using the problem of diffraction of a plane wave by a sphere and a circular cylinder having finite dimensions. The rigorous approach based on a spline basis is used in the case of a dielectric sphere whose wavenumber depends only on the radial coordinate (in spherical coordinates). The two methods are compared for the case of the parabolic dependence of the squared wavenumber of an inhomogeneous sphere on the radial coordinate. The diffraction of a point source field by a metamaterial inhomogeneous sphere is considered.