JournalTOCs

Journal of Communications Technology and Electronics
Journal Prestige (SJR): 0.273

Citation Impact (citeScore): 1
Number of Followers: 2

Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1555-6557 - ISSN (Online) 1064-2269
Published by Springer-Verlag

[2570 journals]

Celebrating the 100th Birthday of Boris Zakharovich Katsenelenbaum
(26.11.1919–26.04.2015)
- PubDate: 2019-11-01
Axial and Helical Metaparticles of Pulse Wave Fields
- Abstract: Abstract—The properties of axial and helical metaparticles of pulse wave fields are presented. An example of emission of such metaparticles by an aperture source is considered. The field width and the energy density of a fundamental (zero) metaparticle in the far field of the radiating aperture are calculated.
  PubDate: 2019-11-01
Two-Dimensional Periodic Dual-Polarized Over Wave Region Antenna Array
- Abstract: The two-dimensional periodic dual-polarized antenna array in the form of a nonuniform multiconductor line of square cross-section conductors is proposed and studied. Using the approximate theory, matching characteristics of the two-conductor line with three different laws of impedance variation are studied and the optimum law is found. Electrodynamic modeling of an infinite two-dimensional periodic array of these elements is carried out using the finite element method at different scanning modes. Using a numerical experiment, the possibility of implementing the over wave region matching mode is demonstrated for arrays of 144 (12 × 12) and 576 (24 × 24) elements: for the array of 576 elements, the working bandwidth in the cophased mode was 1 : 34; when scanning in the sector of 90°, more than 1 : 15.
  PubDate: 2019-11-01
On a Method for Measuring Methane Concentration on Extended Atmospheric
Paths Using a Remote Gas Analyzer with a Powerful Raman Amplifier
- Abstract: Abstract—The paper presents the results of methane concentration measurements on extended horizontal and vertical paths in the Earth’s atmosphere using a laser-generated remote gas analyzer based on a two-stage Raman amplifier with an output power of about 3 W in quasi-continuous mode with linear-frequency modulation of the laser and distributed feedback. An empirical expression of the weight function for anomalous gas distribution is obtained with a maximum concentration at a height of ~700 m and an anomalously low concentration at heights above 1000 m. This distribution agrees well with the experimental data obtained for a situational plan with additional methane emission sources. During measurements, the water absorption line was detected, which strongly depends on atmospheric humidity and can be used to refine weather data and ecological conditions.
  PubDate: 2019-11-01
Using the Method of Base Components for a Heuristic Solution to the
Diffraction Problem on a Half-Plane with Nonideal Boundary Conditions
- Abstract: Abstract—Using the method of base components, a heuristic solution to the diffraction problem on a semitransparent half-plane has been determined. The heuristic formulas have been verified via numerical solution. We have a semitransparency function for describing the transformation of the heuristic formulas upon variation in the transparency parameter of a scatterer.
  PubDate: 2019-11-01
Yttrium Iron Garnet Thickness Influence on the Spin Pumping in the Bulk
Acoustic Wave Resonator
- Abstract: The features of phonon–magnon interconversion in acoustic resonator determine the efficiency of spin pumping from YIG into Pt that may be detected electrically through the inverse spin Hall effect (ISHE). Based on the methods developed in previous works for calculating resonator structures with a piezoelectric (ZnO) and a magnetoelastic layer in contact with the heavy metal (YIG/Pt), we present the results of numerical calculations of YIG film thickness influence on acoustically driven spin waves. We obtain some YIG film thickness regions with various behavior of dc ISHE voltage UISHE. At micron and submicron thicknesses, the higher spin wave resonance (SWR) modes (both even and odd) can be generated with efficiency comparable and even exceeding that of the main mode. The absolute maximum of UISHE is achieved at the thickness about s1 ≈ 208 nm under the excitation of the first SWR.
  PubDate: 2019-11-01
Coupled Plasmon Oscillations in a Cluster Consisting of Three Silver
Nanocylinders with Different Diameters
- Abstract: 2D problem of the diffraction of the TM plane electromagnetic wave by a cluster consisting of three self-similar silver nanocylinders with different sizes is considered. Rigorous numerical procedures are used to study quasi-static plasmon resonances in such a cluster. Frequency characteristics of the scattering cross section and spatial structure of the field in the vicinity of the cylinders are calculated for different angles of incidence of the plane wave, self-similarity coefficients, and diameters of cylinders. It is shown that an increase in the distance between the cylinders is accompanied by degeneration of the resonances of scattering cross section. When real loss of silver is taken into account, electric field at the exit of the cluster cannot be amplified by a factor of greater than 10.
  PubDate: 2019-11-01
Spectra of a Photonic Crystal Containing a Layer with a High Dielectric
Constant
- Abstract: Abstract—The features of the transmission spectra of a one-dimensional photonic crystal are studied, in which the dielectric constant of one of the two layers in the structural period is many times greater than the permittivity of the other. The spectra of a finite defect-free structure, an inversion-defect structure, and a symmetric microcavity structure are considered. The authors demonstrate the possibility of controlling the width of the photonic band gap using an electric field, as well as achieving a very narrow spectral line of the defect mode and an ultrahigh degree of radiation localization at the defect.
  PubDate: 2019-11-01
Electrodynamics of Inhomogeneous 2D Periodic Media
- Abstract: A new method is proposed to represent electromagnetic field in inhomogeneous 2D periodic medium (PM) as a discrete set of amplitude vectors (AVs) each of which contains amplitudes of spatial harmonics of the field scattered by a particular particle. A scattering operator of a particle is introduced to establish a relationship of the amplitudes of harmonics of the scattered and excitation fields, and an external source is introduced to consider the scattering field that is not related to the excitation field of a particle. An exact nonlocal equation is derived for AVs to describe propagation of electromagnetic waves in PM, and an approximate localized difference equation (an analog of the wave equation in continuous medium) is obtained. Quadratic relationships are obtained for AVs: theorem on active power, Lorentz lemma, and reciprocity theorem. A problem of excitation of homogeneous PM by an external source is solved, and the Green function of PM is obtained. Boundary conditions for AV are introduced at the PM defects that disturb periodicity. A method to formulate and solve the boundary-value problem for AVs in PM with defects is proposed. Analytical solutions to canonical boundary-value problems of PM electrodynamics (eigenwaves of homogeneous PM, normal modes of a cavity, and eigenwaves of an infinite waveguide) are considered. Construction of efficient numerical algorithms for solution of boundary-value problems in electrodynamics of inhomogeneous PM is discussed.
  PubDate: 2019-11-01
Edge Catastrophes in Diffraction Problems
- Abstract: Abstract—The application of the wave theory of edge catastrophes to the asymptotic solution of diffraction problems on bodies with curvilinear edges is considered. As an example, the diffraction of a converging scalar wave on a curvilinear ideally conducting screen in a homogeneous medium is studied, leading to the formation of C4 and K4, 2 edge catastrophes.
  PubDate: 2019-11-01
The Method of Integral Equations in the Theory of Antenna Arrays
- Abstract: The method of mathematical simulation of antenna arrays is considered. It is based on the investigation of integral equations and can be applied to a wide range of radiators.
  PubDate: 2019-11-01
Investigation and Evaluation of the Effect of Silicon Layer and Its
Comparison with Water Bolus in Designing Microstrip Antenna for
Hyperthermia Applications
- Abstract: In this paper, the main concern is the designing of microstrip structure for Hyperthermia and tissue heating. The purpose of this antenna designing is the capacity of doing an action in 2.24 GHz Frequency and the usage of Silicone tissue in spite of water bolus to decrease the burn percentage on skin to the least degree and solve the problems caused by the water bolus tissue. The function of the antenna by Moment Method and the frequency analysis method is simulated and developed through several stages and biologic tissue which includes three layers (skin, fat, muscle). The improvement in this antenna is the transformation of heating to the upper part of skin and fat layers. The results have been evaluated in four shapes, water bolus, water bolus—silicon, silicon—water bolus, and silicon alone. In first three shapes, the energy is not capable to permeate into the tissue in higher depths; and, it will stay in the fat tissue. Only when silicon has been used, the energy will permeate into the muscular tissue without any damages to the other body tissues. The size of the antenna (0.84 × 45 × 70 mm) and the coaxial 50 Ω has been used for feeding.
  PubDate: 2019-11-01
Low Elevation Angle Estimation Using an Iterative Array Processing Method
- Abstract: — Multipath phenomenon reduces the performance of elevation angle estimation, intensively. In this study, a precise even symmetry relation and novel iterative array processing method have been presented based on the fixed beam method for estimating the elevation angle of low-altitude targets in specular and diffuse multipath environment. We propose an iterative beamforming process for retaining antenna aperture with precise even symmetry to eliminate multipath. The Kalman filter (KF) prediction have been used to reduce the computational load of the proposed method, and the frequency diversity and KF estimation to smooth sudden fluctuations in angle estimation. The proposed method estimates the elevation angle with very high precision as shown in simulation results in the multipath environment without the need for any advance knowledge.
  PubDate: 2019-11-01
Performance Prediction of a Quantum Well Infrared Photodetector Using
GeSn/SiGeSn Structure
- Abstract: — QWIP using group IV elements have created more interest among researchers for its potential application in optical communication as well as in optical interconnects. This paper presents modeling and theoretical analysis of Sn-based tensile strained type I direct band gap QWIP in which the active region has a multiple quantum well structure formed with Ge0.92Sn0.08 quantum wells separated by Si0.11Ge0.7Sn0.19 barriers. The structure reported by V. Ryzhii et al. has been reproduced and the parameters like responsivity, power density and the dark current density have been analytically calculated. A comprehensive comparison of responsivity and power density of this proposed structure with the existing QWIP structure made of GaAs/InGaAs is reported here. An improvement in the field of responsivity is observed with the proposed model. The reduction of threshold power density corresponds to an effective operation of the QWIPs in incident infrared radiation. The intersubband electron transition and tunneling electron injection effects are considered here to predict a better performance of the proposed structure operated in infrared region.
  PubDate: 2019-11-01
Ionospheric Decontamination Method Based on Optimization Criteria in
Over-the-Horizon Radar
- Abstract: — Over-the-horizon (OTH) radar is important equipment for wide-area surveillance; it has several uses, including aircraft tracking, ship and missile detecting, and remote sensing of the ocean surface. OTH radar uses high frequency electromagnetic wave which propagates by means of refraction within ionosphere; it can provide large range coverage. But this will cause phase contamination due to the unstable movement of the ionosphere. The spectrum of sea clutter and target will be expanded by the ionospheric contamination in the Doppler domain, which will cause the ship target more difficult to separate from the clutter and even buried in the clutter. A new decontamination method is proposed to solve this problem. By analyzing the sea clutter signal model, the proposed method designs an ideal optimized matrix and then uses optimization criteria to estimate phase contamination. Based on the real data, the effectiveness of the new method was validated and compared against other methods.
  PubDate: 2019-11-01
New Functional Capabilities of Microwave Interferometry When Using
Metastructure as a Tunable Beam Splitter
- Abstract: — It is experimentally shown that the microwave metainterferometer with a metastructure (metasurface or metaatom) as a tunable beam splitter possesses the unique possibility to specify selective magnetic and electric tuning of multiband filtration of electromagnetic waves. The investigation results are shown concerning the interferogram of a modified metainterferometer based upon the waveguide tee junctions in which the metastructure contains a ferrite plate or a structure made of conducting resonant elements compatible with the controlling elements or their combination with ferrite. The dependences of the shape, width, intensity, and frequency of the interference band on the value and sign of a magnetostatic field, on the relative position of ferromagnetic resonance and the band, and on the electric voltage on the varactors included in the discontinuities of elements. We have experimental results that open new methods and approaches in the design of switchable and tunable multiband microwave filters needed in multifunctional multichannel telecommunication systems.
  PubDate: 2019-11-01
Acquisition and Analysis of Multi-Global Navigation Satellite System
Signals Based on Fast Fourier Transform
- Abstract: — This paper presents an essential technique for acquiring multi-GNSS signals using FFT. The fundamental approach of multi-GNSS satellite navigation is that the navigation information transmitted with the help of stand-alone GNSS system of numerous constellations is acquired by the receiver. The reason for the acquisition is to apprehend how many total numbers of satellites are currently visible to the user segment; also, the acquisition must determine the code phase and frequency of satellite signals. Although, there are three search domains, which are Doppler frequency, code phase, and code identification, in the acquisition processing, the emphasis of this paper will be on the search of the code phase. FFT based acquisition can decrease acquisition time of DSSS signals due to an increase in the power of DSP chips. The use of FFT based algorithms to perform acquisition of Direct Sequence Spread Spectrum (DSSS) is still the hot topic of research. The main purpose of this study is the analysis of the Multi-GNSS signal acquisition process using the Fast Fourier Transform (FFT) method. Based on MATLAB software platform; GPS, GLONASS, and BeiDou signals are acquired from the real IF signal records of GPS, GLONASS, and BeiDou. The output results of the FFT based acquisition are presented and discussed.
  PubDate: 2019-11-01
Promotion of Improved Discrete Polynomial-Phase Transform Method for Phase
Parameters Estimation of Linear Frequency Modulation Signal
- Abstract: The discrete polynomial-phase transform (DPT) method estimate chirp rate and central frequency of LFM signal based on sequential estimation of polynomial phase parameters. DPT method which has been developed by an iterative approach as Improved DPT method uses nonlinear least squares (NLS) technique to estimate phase parameters of the LFM signal. NLS have high computational load. In order to promote the precision of estimation and reduce the computational load in Improved DPT method, combined technique is proposed and used which provides an initial estimation of frequency interval based on NLS criterion in single-exponential mode and using random basis functions method.
  PubDate: 2019-11-01
Speaker Modeling Using Emotional Speech for More Robust Speaker
Identification
- Abstract: — Automatic identity recognition in fast, reliable and non-intrusive way is one of the most challenging topics in digital world of today. A possible approach to identity recognition is the identification by voice. Characteristics of speech relevant for automatic speaker recognition can be affected by external factors such as noise and channel distortions, but also by speaker-specific conditions—emotional or health states. The improvement of a speaker recognition system by different model training strategies are addressed in this paper in order to obtain the best performance of the system with only a limited amount of neutral and emotional speech data. The models adopted are a Gaussian Mixture Model and i-vectors whose inputs are Mel Frequency Cepstral Coefficients, and the experiments have been conducted on the Russian Language Affective speech database. The results show that the appropriate use of emotional speech in speaker model training improves the robustness of a speaker recognition system – both when tested on neutral and emotional speech.
  PubDate: 2019-11-01
Features of Constructing an Orthonormal Basis Based on Atomic Functions as
Applied to Solving Boundary Value Electrodynamics Problems for Regions of
Complex Shape
- Abstract: — A method for orthonormalizing atomic functions is proposed and substantiated. The efficiency of using a basic system to solve a number of boundary value electrodynamics problems is shown. Numerical experiment and analysis of the physical results showed that the R-functions method combined with basis functions is universal for waveguides and resonators of arbitrary shape.
  PubDate: 2019-11-01