Vol 62, No 8 (2017)

A 2D periodic array of coupled slot transmission lines is considered in the approximation of equivalent boundary conditions. The eigenmode problem for an array operating in the quasi-periodic mode is formulated and solved. The dispersion equation for eigenmode propagation constants and expressions for eigenmode fields are obtained. The behavior of eigenmodes in a frequency band and in a range of values of geometric parameters is analyzed. The orthogonality of eigenmodes is shown. Theoretical results are compared to the results of numerical calculation performed with the use of electromagnetic simulation systems.

A three-dimensional vector problem of plane-wave diffraction by a two-layer finite array of perfectly conducting bodies of revolution is considered. The problem is solved under the assumption that the sizes of the elements of the array are small as compared to the wavelength. The approach proposed was tested by comparing the far-field patterns of an array with a small number of elements, calculated by two different methods. Angular dependences of the far-field patterns of arrays of elements in the form of spheres, oblate spheroids, and superellipsoids of revolution are constructed. Dependences of the plane-wave reflection and transmission coefficients on the angle of incidence for single-row finite and infinite arrays are presented.

The process of focusing of surface electromagnetic waves on impedance guiding surfaces is considered in the ray approximation with the help of a 2D model of a plane surface. An estimate of the influence of the wave properties of the field on this process is given.

Quasi-optimal synthesis of digital phase-locking systems (PLSs) is discussed to evaluate the information parameters of a frequency-modulated signal. An adaptive Kalman filter capable of functioning without a priori data on the statistical characteristics of input and test noises is employed. The model of the process under study is identified using the linear trend modified by the self-organization algorithm. Procedures and the results of numerical calculations are presented for the digital system of phase synchronization.

Expressions for effective permittivity of a periodic semiconductor–insulator structure with both n- and p-type semiconductor layers are derived in the approximation of shallow-layer medium. Dispersion relations are obtained for the TM wave that is controlled by external magnetic field with allowance for different propagation directions of the wave relative to the periodicity axis of the structure. Specific features of the transmission spectrum of wave are revealed for a layer of shallow-layer medium with finite thickness at several ratios of layer thicknesses in the period of structure.

Principles of the development of high-power pulsed X-ray sources based on explosive emission from carbon nanoclusters are stated. Designs and main parameters of the developed X-ray tubes ( the electron flow exciting the X-ray radiation is 100−500 А, the voltage is 20−150 kV, the pulse length is 10−20 ns, and the nanosecond pulse repetition rate is 1−10³ Hz) are reported.

The issue of long-term automatic determination of the human sleep structure through the analysis of respiratory movements and motor activity recorded using bioradiolocation is considered. An algorithm for the determination of the human sleep structure is developed. The potentiality of determining the sleep structure with an average quality of 0.5 Cohen’s kappa relative to the “gold standard” (polysomnography) for apparently both healthy test subjects and insomniacs is demonstrated.

The dynamics of forming and resistive switching in Au/iron oxide/Pt structures based on magnetite (Fe₃O₄) is investigated. It has been revealed that these processes have an electrochemical nature and are accompanied by formation of low-resistance conductive filaments formed by inclusions of magnetite in the matrix of high-resistance maghemite (γ-Fe₂O₃). It has been found that the electric field stimulates reversible redox reactions in iron oxide. The direction and rate of these reactions are determined by the polarity and the amplitude of voltage pulses. The possibility of setting the resistance of the structure by changing the amplitude of the “record” voltage pulses opens prospects for the development of multilevel memory elements.

Models of plane unipolar and bipolar diodes are used to study effects related to additional injection of ions from permeable hot cathode. An experimental scheme for verification of the model is proposed, and the main parameters of the scheme are estimated for a well known variant of electron gun.

Reversible functional failure of an ATmega 8515 microcontroller (MC) is used to demonstrate the importance of internal stripes of chips in radio-transparent package in the analysis of susceptibility of microelectronic components to radio-frequency radiation. Experiments under different conditions for MC irradiation are performed and induced electric voltages are calculated using the simplest model of antenna reception. The calculated results are in qualitative agreement with the experimental data.

New selective properties are revealed of the base section of conventional microstrip filters with circuits based on a four-wire system of coupled quarter-wave lines with one half-wave hairpin resonator. The conditions under which this single-resonator section acquires the characteristics of multi-resonator circuits due to the possibility of formation of four zeros and six operating attenuation poles at the end frequencies are determined. The structure does not contain elements short-circuited to the screen, which determines its high manufacturability. It is demonstrated that high-selectivity compact microstrip filters can be designed on the basis of single- and dual-resonator structures, i.e., the structures with the minimum number of resonators.