Abstract The paper presents a method for calculating the radiation patterns (RP) of dual-reflector antenna systems taking into account the electrodynamic interaction between reflectors. This method is suitable for use in the resonance range of wavelengths with respect to the main dimensions of reflectors. The method is based on the iteration procedure proposed by the authors. Each iteration involves

Abstract A compact quad-band circularly polarized (CP) G-shaped printed antenna with square slot is proposed in this paper. Two semicircular notches have been etched from lower periphery of the ground to increase the impedance bandwidth (IBW). In order to increase significantly the axial ratio bandwidth (ARBW), a spring-shaped notch is etched from the upper periphery of the ground. For further increase

Abstract Changes in the geometric parameters of ring coils, which are an essential element of transducer design used for non-destructive testing of ferromagnetic metals, entail a change in the self-induction coefficient (inductance) of alternating magnetic field source. In the article, on the basis of proposed approach [1], the equations for determining the ring coils inductance are obtained, allowing

Abstract Two symmetrical third-order microstrip bandpass filters (BPF) with all mixed coupling coefficients are proposed and analyzed. The first filter is a combline filter with stepped impedance resonators (SIR) closely spaced to each other. This leads to mixed couplings between adjacent resonators. The cross coupling of the end resonators is also mixed K13 = Km13 + Ke13 (MCC). Its magnetic component

Abstract The possibility of sensitivity increasing of magnetic field sensors by combining different types of sensitive elements in one sensor circuit is experimentally investigated. For this purpose, four new sensor constructions are proposed: based on bridge circuit, based on magnetotransistor in combination with magnetodiode or with second magnetotransistor and with frequency output. More thermostable

AbstractThe use of bio-medical applications and bio-inspired computing facilitates the diagnosis of human health. The main work of bio-medical applications relies mostly over the biosensors. Biosensor construction are based on piezoelectric, chemical, optical or electronic principles. Field Effect Transistor (FET) based biosensors gain popularity because of some distinct advantages like compact, fast

AbstractIn order to accurately analyze the most vulnerable fracture points of normal human lumbar vertebrae under upright position, walking and left-right rotation, the spiral computer tomography (CT) was used to scan the segment from the upper edge of lumbar vertebra L1 to the lower edge of lumbar vertebra L5. After reading CT images with Mimics software, the threshold analysis, area segmentation

AbstractAn analysis of complex dielectric permittivity and characteristic impedance of micromechanically tunable coplanar line is presented. The coplanar line parameters tuning is achieved by signal line electrode movement above the substrate or the dielectric plate above the surface of line electrodes. A reconfiguration of electromagnetic field with complex nature occurs as a result of such movement

AbstractInterpretations of large electromagnetic parameters and giant effects in electronic materials are presented. Conductivity, permittivity and permeability of certain materials can be hundred times higher than normal values. Physical phenomena of magnetoresistivity, nonlinear resistivity, electrostriction, magnetostriction, magnetocaloric and thermistor effects in some materials appear to be giant

AbstractSince ancient times, human beings began to understand the periodicity of their own activities. In modern times, people gradually found that the movement of living matter followed a specific space-time law and put forward the concept of biological rhythm. The biological rhythm of human body is a cycle theory that takes the body of each person as a research object and reveals the laws of physical

AbstractIn this paper by means of physical modeling method we obtain the algorithms for calculation of magnetic permittivity in ferrite in case of arbitrary values of magnetic intensity of electromagnetic wave and force of standing electromagnetic wave impact on ferrite cylinder of arbitrary diameter which is placed into constant magnetic field. A value of constant magnetic field intensity provides

AbstractThe noise immunity of radars is essentially reduced under the simultaneous exposure to active noise and passive interferences. This is stipulated by the passive interference decorrelating the active noise and also by the disruption of interperiod correlation of passive interference during the adaptation of weight coefficients of spatial filter. This paper proposes and investigates a new method

AbstractThe paper presents the substantiation of algorithm for forming the structure and technique for message transmission in unidirectional radio communication systems. The proposed algorithm is intended for use before the beginning of signal transmission for implementing the single-use reliable transmission technique with delayed acknowledgement, but with the possibility of forecasting the interference

AbstractThe main aim of massive multiuser multiple-input multiple-output (MU-MIMO) system is to improve the throughput and spectral efficiency in 5G wireless networks. The performance of MU-MIMO system is severely influenced by inter-antenna interference (IAI) and multiuser interference (MUI). The IAI occurs due to space limitations at each user terminal (UT) and the MUI is added when one UT is in

AbstractA method of synthesis of odd-order I/Q demodulators based on replacing the multistage demodulation schemes with equivalent single-stage ones is proposed. The calculation of coefficients of single-stage odd-order I/Q demodulator, which is equivalent to multistage scheme in terms of the waveform of its amplitude-frequency characteristic (AFC), is based on the sample-wise analysis of the process

AbstractElectro-acoustic transducers of electromagnetic type are mainly use in modern non-destructive monitoring and technical diagnostics devices of metal products. The influence of a measuring device on parameters of recorded signals, i.e. on the measurement results, can be eliminated if the influence of dimensions of emitters and receivers of alternating magnetic field on the efficiency of generation

AbstractIt is considered a technique of mutual application of multi-antenna MIMO systems and multiplexing with orthogonal frequency division of OFDM channels for current-technology systems of wireless communication of special application. There are defined areas of prior application of time and frequency variant of diverse signals transmission according Alamouti principle for wireless channels with

AbstractThe paper proposes a new numerical measure for filtering quality assessment of additive white Gaussian noise in digital images based on the analysis of closeness of the difference image to white noise. Such analysis is often conducted visually that leads to undesirable subjectivism. The numerical analysis of difference image using the properties of nonparametric BDS statistic was performed

AbstractA circularly polarized (CP) CPW-fed (CoPlanar Waveguide) with two asymmetric U-shaped strips, patch antenna is described in this paper. The antenna consists of a radiating patch composed of a hexagonal-ring connected with two annular rings on the two corners, which provide wide CP. The CPW-fed antenna was constructed by etching out two L-shaped slots and adding two asymmetric U-shaped strips

AbstractThe ruggedness of emerging single adaptive approach that performs well in all types of operating conditions has led to the development of composite adaptive strategy. In this regard, the fusion of particular decisions of single adaptive schemes through suitable fusion rules can provide a better final detection. Particularly, the fusion of cell-averaging (CA), ordered statistics (OS) and trimmed-mean

AbstractApplication of multi-frequency radiolocation allows to expand essentially received signals spectrum that increases amount of a target (object) classification identifiers including thermal portraits for radiometric measurements. In this paper it is represented a prototype of measuring radiometric unit allowing to carry out simultaneously contactless radiometric research of liquids in two wavelength

AbstractThe digital compensation process for nonlinearly inertial characteristic of the transmit path of dual-band communication system with concurrent data transmission in the presence of unbalance of modulator quadratures has been considered. Analytical relationships enabling us to identify adaptively or change the parameters of dual-band polynomial model of corrector with due regard for the modulator

AbstractAnalysis of discrete estimates of bi-periodically correlated random processes (BPCRP)—mathematical models of signals with double stochastic periodicity was performed using least squares (LS) technique. It is shown that LS utilization allows to avoid systematic errors related to leakage effect. Expressions for estimate bias and dispersion were obtained, allowing determination systematic and

AbstractA new statement of the problem on the calculation of kinematic and dynamic characteristics of surface acoustic waves in piezoelectric monocrystals is proposed. A procedure for solving the above problem is also proposed with due regard for the existence of electric field scattering on the crystal surface not covered with electrodes and the vortex component of electric field in the general case

AbstractSpatial correlation is a crucial impairment for practical Multiple Input Multiple Output (MIMO) wireless communication systems. It is important to consider spatial correlation between antennas in actual communication scenario at both sides, i.e. transmit and receive side. Furthermore, we have considered nonorthogonal full rate STBC in MIMO systems equipped with four transmit antennas and four

AbstractThis paper describes the development of embedded software for the implementation and testing of the artificial multistable neuron model’s basic behavior with the help of the hardware architecture of programmable logic integrated circuits (FPGA). The real behavior and function of the biological neuron with linearized activation characteristics are investigated and implemented in the programming

AbstractSpace-time-frequency (STF) coding can obtain the diversity gain from three dimensions (space, time and frequency) to effectively improve the transmission performance of the multi-input multi-output (MIMO) relay system. In this study, a MIMO one-way two-hop amplify-and-forward (AF) relay communication system is presented by means of triple Khatri–Rao space-time-frequency (KRSTF) coding, which

AbstractThe quality of reception of radio signals at the destination is greatly influenced by the type of signaling schemes used and the use of multiple antennas at the output of transmitter and the input of receiver. However, this configuration usually causes InterCarrier Interference (ICI), which leads to distortions. In this paper, the performance of 6×6 multiple antenna beamforming in offset 16

AbstractIn this paper, two digitally-controlled ring oscillators (DROs) with similar structure but different constructive cells have been proposed. These proposed DROs include of 5 stages, and each stage contains 10 parallel delay cells. In addition, each stage has fine and coarse parts for adjusting the output frequency. The proposed designs have a wide frequency range and high frequency. The frequency

AbstractIn this paper, we present the radiated mode indoor radio coverage performance study of a co-existing dual technology, dual 4×4 Multiple Input Multiple Output (MIMO) antenna platform. The antenna platform is targeted to be used for low power wireless radio Base Station (BS) applications. One of the 4×4 MIMO antenna pairs operates in the 2.5–2.7 GHz licensed Long Term Evolution (LTE) band while

The numerical optimization results of constant thickness septum polarizer’s performances for various operating fractional bandwidths (FBW) are presented in the paper. The polarizer’s structure includes a common input square waveguide, a constant thickness septum with several steps, and two output rectangular waveguides. The polarizer design of 2-, 3-, 4-, and 5-step septums is optimized for different

The exact knowledge of the clutter properties is of great importance for modern radar systems due to the role that they are directly play mainly through the CFAR processor design in the optimization of the detection process. Owing to the central limit theorem, the most used models are of Gaussian distribution that has the feature of simple processing architectures. Actually, these models are expected

This paper describes the algorithm of antenna array (AA) calibration, which estimates and compensates phase lags, caused by non-identical electrical characteristics of array channels. The algorithm does not require the access to the channel signals or the channels disabling. It uses only the array output power measurements under the specific channel phase perturbations. The algorithm accuracy equals

It is considered a problem of automatic speech recognition at basic, phonetic level of speech signal processing. It is researched a problem of noise-immunity increase. For its solution it is proposed a criterion of minimum information divergence of the signals with tuning to a speaker voice and automatic scaling of speech template to thin structure of observed (current) speech frame. An example of

Two methods have been proposed for enhancing the accuracy in determining the coordinates of radio emission sources by using phase systems based on reducing the dynamic and random errors in terms of the curvature of electromagnetic wave phase front during processing the signals at inputs of linear antenna array. The reduction of dynamic errors stipulated by the limited number of terms of the Maclaurin

In this paper it is represented an efficient method for calculation of periodic stationery states of non-linear electronic circuits at time domain. The method is based on application of Kotelnikov-Shannon series for approximation of derivatives of mathematic models of the circuit. Cyclic approximation form with application of Shannon kernel allows to obtain simple matrix relation for the derivatives

The paper considers the problem of determining the eigenfrequencies of biconical cavity making it possible to simplify the eigenfrequency-based design of devices. We used the solving of the excitation problem for biconical cavity using the method of partial intersecting regions in combination with the collocation method. Based on the concept of the search of quasisolution for determining eigenfrequencies

A compact ultra-wideband circular monopole antennas with single, dual, triple and quad-band rejection characteristics are proposed in this paper. The antenna units are designed using RT/DUROID substrate with permittivity 2.2 and all are fed through a coplanar waveguide (CPW). In the proposed antennas splitted concentric rings (SCR) are used to achieve band rejection characteristics. The proposed antennas

In this paper, we consider Mt×M system (Mt > M), where Mt and M are the numbers of antennas at the transmitter and receiver, respectively. We select M out of Mt transmit antennas using two different antenna selection schemes. In scheme 1, we select the subset of M antennas out of total \((\begin{array}{l}{M_{t}} \\{M}\end{array})\) subsets. In the selected subset, the minimum SNR is maximum compared

Synchronization is a complex task in uplink Orthogonal Frequency Division Multiple Access (OFDMA) for Mobile WiMax as each user presents different Carrier Frequency Offsets (CFO). Synchronization begins with the CFO estimation and followed by the compensation of residual CFO present in the received signal. This paper deals with various techniques in time and frequency domains to compensate the effect

The method of Principal Informative Components (PIC) is presented for problems of statistical measurements, where the signal to be measured cannot be directly observed. Such situations include image reconstruction, system identification, communication channel reversal, media tomography, etc. The common feature of such problems, usually, is instability of their solutions to small variations of initial

Discrete orthogonal transforms including the discrete Fourier transform, the discrete Walsh transform, the discrete Hartley transform, the discrete Slant transform, etc. are extensively used in radio-electronic and telecommunication systems for data processing and transmission. The popularity of using these transform is explained by the presence of fast algorithms that minimize the computational and

MIMO technology not only offers diversity and capacity gains, but also provides higher spectral efficiency and significant link reliability over SISO systems. Many methods are developed to exploit the diversity offered by multi-antenna systems such as Alamouti code and spatial multiplexing that do not require transmitter-side channel status information (Tx-CSI). Other power allocation optimization

The paper investigates the efficiency of transformation of traveling wave into radiation in longitudinally inhomogeneous plasma cylinder. The plasma is limited by a dielectric shell of finite thickness. The investigation involves the use of the method of spectral field expansion in terms of a set of functions including the surface and spatial waves of plasma cylinder with dielectric shell. A system

In this paper, a novel T-shaped compact Dielectric Resonator Antenna (DRA) is proposed for wide band application. The proposed antenna covers C- and X-band. Two different techniques namely partial ground plane and multi stacked elements have been used in the designing of the proposed antenna to improve the performance of the antenna. It is observed that the air gap between two dielectric materials

In this article a novel planar triple-band microstrip monopole antenna with circular polarization and high efficiency is presented for wireless communications applications. This antenna with passbands at 2.4, 3.5, and 5.5 GHz is able to cover WLAN and WiMAX applications according to the IEEE 802.11b/g and IEEE 802.16 standards. The proposed antenna consists of a C-shaped stub to control the circular

Analytical consideration of lower bound (LB) analysis of the spectral efficiency (SE) of downlink transmission of Hyper MIMO (H-MIMO) system is important to obtain insights in the role of various factors that are involved. In this paper, we derived a mathematical expression for lower bound of the SE of an H-MIMO system with linear precoding techniques such as zero-forcing (ZF) and minimum mean square

FBMC-OQAM is reflected as one of the most capable techniques for the next generation mobile communication namely 5G. It has several advantages as compared to orthogonal frequency division multiplexing (OFDM) but it also has some drawbacks like high peak power. Filter bank multi-carrier (FBMC) employs a group of filters at the transmitter and the receiver part of the system. The high peak power decreases

A printed planar antenna having compact dimensions of 0.35×0.25λ, mm2 and fed by a microstrip line for wideband applications is presented. The proposed antenna consists of a radiating patch, a new arc-shaped strip, microstrip feed line, and a rectangular stub loaded ground plane. Furthermore, the ground plane of the fundamental radiator is modified to improve the voltage standing wave ratio (VSWR)

Complex application of radar information of the systems of different ranges allows to increase the efficiency of radar detection of the objects on a background of interferences from sea surface. Reflection characteristics of a sea in centimeter and millimeter wavelength range and restrictions related to their correlation property are the objects of researches and description in this paper. In this

The article presents the results of experimental studies of the TerraStar service, which implements autonomous real-time PPP (Precise Point Positioning) technology. The service provides high-speed orbital and clock data of GPS, GLONASS, GALILEO, BeiDou navigation satellites received from more than 100 global navigation satellite system (GNSS) ground stations. These data, together with the algorithms

The theory of parametric time varying circuit is of interest as an introduction to the theory of nonlinear circuit. As follows from the principle of linear representation, which is little known in radio electronics, it is advisable to select for analysis the parametric time varying circuit in the most general form. The significance of ordinary circuit for practice is stipulated by the phenomenon of

The authors have investigated the bit-error rate (BER) performance of Reed-Muller coded cooperative single-carrier frequency domain equalization (RMCC-SC-FDE) scheme and Reed-Muller coded cooperativeOFDM(RMCC-OFDM) scheme incorporating multiple relays and multiple antennas. The maximum ratio combining (MRC) technique is utilized for OFDM/SC-FDE signal detection at the destination terminal. The joint

The Hilbert-Huang transform (HHT) is a classic method in time-frequency analysis field which was proposed in 1998. Since it is not limited by signal type, it is generally applied in medicine, target detection and so on. Empirical mode decomposition (EMD) is a pre-processing part of HHT. However, EMD still has many imperfect aspects, such as envelope fitting, the endpoint effect, mode mixing and other

A circular slotted reconfigurable antenna for WIMAX and X-band wireless communication applications is presented. The aim of this article is to design an antenna, which can operate at dual band with high gain. The designed antenna is compact in size with dimensions 32–24 mm.CPWfeeding is used in the design of frequency reconfigurable antenna, and BAR-64-20V PIN diodes are installed for frequency tuning

Electromagnetic eigenwaves in a weak ferromagnetic with anisotropy of the “easy plane” under magnetization in this plane are investigated. It is shown that at frequencies of anti-resonances the weak ferromagnetic can be considered as environment with characteristic impedance close to zero. The polarization of eigenwaves in such environment is analyzed on the example of high-temperature weak ferromagnetics—hematite

Statistical characterization of ground clutter information for radar systems is a topic that requires a detailed understanding. In this work, we characterize the ground clutter information from data captured by two Frequency Modulation (FM) based passive radar systems placed at different locations in the Czech Republic. Since the target models are statistically defined by the Swerling models, each

In this article an S-shaped rectangular microstrip patch antenna (RMSA) is investigated for S-band applications using artificial neural network (ANN). The authors have done the parametric study of different radiating structures to obtain S-shaped RMSA. The size of inserted notches on the radiating patch for achieving wideband operation is computed through multilayer perceptron artificial neural network

Equivalent circuit model of a coaxial probe-fed quasi-lumped element resonator antenna is proposed. The proposed resonator is a periodic interdigital lumped element structure whose resonance does not depend on the electrical length but instead on some intrinsic circuit components, with attendant small size as a premium. The derived equivalent circuit components are extracted using the Agilent Advance

In the modern age, wireless communication has taken on a wide range of applications in different aspects of a human life. Ever increasing demand for higher data rates led the interest of research in FBMC (Filter Bank Multi-Carrier) as a new transmission system for the next-generation mobile communication system. FBMC is a multicarrier technique which utilized filters at the transmitting and the receiving