Vol 21, No 4 (2018)

This article is devoted to the development of correct methods of electrodynamic analysis of microstrip antennas with substrates of chiral metamaterials. The method of analysis of such antennas based on the method of singular integral representations of the field and the method of surface impedances is proposed. A singular integral equation for the unknown function of the current density distribution over the radiator is obtained. Two methods of solving this equation are shown: the method of moments and the method of partial reversal of the operator. A convergence study was conducted. The approbation of the proposed method on the example of solving the test problem using the Feko software complex is performed.

The paper considers a metal step in the H-plane of a rectangular waveguide. Modeling of inhomogeneity in the environment of Microwave Studio was carried out. The results of the simulation confirm the validity of the theoretical expressions obtained.

In the present paper we studied the entanglement of a quantum system consisting of two dipole-coupled two-level atoms, one of which interacts with one-mode thermal field in a lossless cavity, and another is outside a cavity. We obtained the analytical expression of the atom-atom negativity for separable initial atomic state and investigated the influence of a detuning between the atom and the field frequencies and direct dipole-dipole interaction on an atom-atom entanglement. We derived that detuning might cause high atom-atom entanglement in the presence of the dipole-dipole interaction. We also showed that the detuning and dipole-dipole interaction are an effective mechanisms for control and operation of the atomic entanglement.

The nonlinearity of oscillatory system is a source of the higher harmonicas of the base frequency. Harmonicas distort a form of oscillations and complicate their dynamics. In work the new mathematical model of the classical nonlinear phenomenon - a nonlinear resonance is offered. The model describes a resonance in discrete time. Her feature consists in strict monochromatic of the compelled oscillations of the nonlinear oscillator. The method of equivalent (harmonious) linearization, popular in the applied theory of nonlinear oscillations, is the cornerstone of model. The property of monochromaticity of discrete oscillations is confirmed within the numerical experiment.

The issues of quasi-optimal signal processing in conditions of simultaneous effect of additive and multiplicative non-Gaussian noise are considered. The resulting expression describing the effect on the value of the normalized a posteriori errors of additive and multiplicative non-Gaussian noise. It is shown that with given a priori information about probability density function of the multiplicative noise, the accuracy of the measurement of the information parameter of the signal, in the case of its slow fluctuations can be significantly worse than in the case of rapid fluctuations of multiplicative noise.

We investigate the effect of external optical injection on the dynamics of the vertical cavity surface emitting laser under asymmetrical triangular modulation theoretically. The vertical cavity surface emitting laser with asymmetrical current modulation emits irregular optical pulses both in amplitude and in polarization. In this paper we demonstrate that optical injection leads to stabilization of laser output. Laser with injected signal emits regular subnanosecond optical pulses. Dependence of statistical characteristics of emitted pulses from injected signal parameters is investigated.