Vol 64, No 5 (2019)

The problem about the eigen waves of the infinite periodic lattice of rectangular dielectric rods located in a plane waveguide is considered. The boundary value problem is solved with the partial domain method, and the dispersion equation for the propagation constant of an eigen wave is obtained. The fields of eigen waves are found. The expression for the characteristic impedance of the fundamental wave is obtained. Results of the numerical investigation of the behavior of the moderating ratio and the characteristic impedance of the fundamental wave of the lattice are presented.

Based on the solution to the problem of diffraction of an electromagnetic wave normally incident onto a multilayer array of resistive elements, the dispersion of the effective permittivity of a structure comprised of resistive squares placed into a dielectric layer is calculated. It is established that the dispersion has a relaxation character. The feasibility of controlling the dispersion characteristic in a wide range by varying the parameters of the structure is shown. The ratio of the wavelength to the period of the structure at which the structure under consideration is adequately represented by a homogeneous layer is estimated.

Finite-element method is used to construct electrodynamic models of cylindrical phased antenna arrays using bicones and fragments of bicones. Numerical experiments are used to study scanning characteristics of cylindrical phased antenna arrays with different numbers of biconical elements. Phase relationships of the elements are optimized for minimization of side lobes. It is shown that the ultrabroadband regime of the cylindrical phased antenna arrays can be implemented using circular scanning in the Н plane.

The synthesis procedure of a waveguide multiplexer with a modified structure is considered. Compared with standard methods, the approach to the synthesis of this structure is based on the principle of decomposition, to simplify and accelerate the development of complicated devices. To check the performance ability of a proposed structure, the three-channel X-band waveguide multiplexer with a modified design of channel filters was synthesized. Design and experimental results are compared.

Stimulated oscillations of magnetization and elastic displacement in a normally magnetized ferrite plate with magnetoelastic properties are considered. Frequency multiplication at the ratio determined by the multiplicity of the resonance frequencies of the magnetic and elastic subsystems is analyzed. Time and amplitude characteristics of the effect are studied using a model of the impact excitation of the elastic system due to short-term effect of the magnetic system. Frequency division in the same scheme of the magnetostrictive transducer is employed for comparison.

A technique to take into account the initial transverse electron thermal velocities in converged sheet electron beams has been developed. This determines the main integral characteristics of a thermal beam in a gun and transportation region of the paraxial approximation via chosen characteristic electron trajectories. We have equations of characteristic electrons motion, initial conditions to solve equations, and formulas for the current density distribution in the thermal beam cross-section and current fraction in conventional boundary. The derived equations and formulas may be used in modeling electron-optical systems and choosing parameters in which the effect of heat electron motion on beam characteristics will lie within tolerable limits.

The method of equivalent systems is used to simulate resonator slow-wave structures of beam-plasma devices. A collisionless plasma is considered as a filler for the drift channel. The adequacy of the model is shown by comparing the calculation results with known experimental data. The dispersion characteristics of slow-wave systems are analyzed. The structure of the high-frequency unit of a beam-plasma traveling wave tube is developed, and the parameters of the tube are evaluated using the VEGA code.

In this paper, we studied the functional failure of microcontroller (MC) ATmega8515 under ultrashort pulse series action at clocking frequencies of 1, 8, and 15 MHz. We analyzed the probabilities of occurrence in various types of failure and their connection with clocking frequency and magnitude of field strength. The correlation of MC failure with its operation phase is shown. The possibility to study, at least qualitatively, the behavior of complex electronic systems using well-known mathematical models was demonstrated.