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Nowadays, the actual problem of development and usage of mobile communication devices is to solve problems of optimization of structures and characteristics of antennas of mobile terminals. One of the key criteria for evaluating the operation of the mobile terminal, operating near a human, the accepted value is SAR - Specific Absorption Rate. The purpose of this work is to study the dependence of...
Advantages of the diamond dipole antenna as an active antenna are presented. Such an antenna is like an inverted bow-tie antenna, but the former has some advantages over the ordinary bow-tie antenna. It is shown that the diamond dipole antenna may be an effective element of a new antenna array for low-frequency radio astronomy as well as a communication antenna.
The paper analyzes a possibility of using the verified by international scientific organizations calculation methods of signal attenuation and field intensity along the radio wave propagation path for assessment of electromagnetic compatibility of wideband radio monitoring stations equipped with radio electronic facilities of various purposes.
The paper consideres a complex method of accounting for the influence of radiation patterns on electromagnetic compatibility and accessibility of wide nomenclature range of antennas of the general-purpose electronic systems. Simulation results are given.
It is difficult to synthesize the antenna directly in practical lessons in general theory of antennas with students. The approximate method is proposed for solving the synthesis problem based on the minimization of the functional representing the distance in the functional space with a quadratic metric between the normalized desired antenna pattern (AP) and some normalized AP with unknown amplitude...
Transient radiation of a dipole corresponds to excitation of a spherical harmonic wave in some conical line from an evanescent wave domain. The governing equation contains a cut-off frequency that depends on radius. Using high refraction index material the cut-off frequencies for the radiating mode can be significantly reduced. This can lead to “tunneling” energy from the evanescent region and consequently...
The paper investigates, with the help of the Stokes parameters, the polarization field structure of a retrodirective antenna array with the phase fluctuations in devices forming the orthogonal field components in the radiator aperture. Peculiarities of the Stokes parameters as applied in the statistical antenna theory are pointed out. Specificity of errors in the Van Atta arrays is noted, their influence...
The paper considers conception of synergetics conformably to investigation of nonlinear parametrical zonal systems operating on ultraharmonics in higher zones of oscillations instability as variety of resonance electromagnetic systems.
Energy efficiency and fail-safety of modern wind turbines (WT) are largely determined by their ability to the temporal “tuning” under the spatial variability of the wind field.
The influence of various types of apodization on the eigen parameters of the distributed Bragg reflector, layered Bragg reflectors and resonators has been analyzed. The conditions of reduction of the quality factor of unwanted side Bragg oscillations in quasiperiodic apodized resonators have been determined. It has been proposed the construction of periodic and quasiperiodic structures and apodized...
For six-port vector analyzer based on the E-plane waveguide cross-connection of rectangular waveguides, the benefits of determining the values of the complex reflection coefficient with the application of the principles of holography with three reference signals were approved. The value of the condition number of the matrix system of linear algebraic equations formed according to the methods processing...
The results of experimental measurements of the parameters of antenna-feeder devices using the X-shaped analyzer of the complex reflection coefficient in three modes: at fixed-frequency, vibration meter, vector panorama were presented.
The problem of creating meter of complex reflection coefficient based on the electromagnetic approach using E-plane dividers is studied. A rigorous electromagnetic model of direct and inverse problems of five- and six-port measurements of complex reflection coefficient is derived. Frequency dependencies of model parameters are calculated. Properties of E-plane junctions are investigated. Approximations...
A concept of providing wireless power supply with microwave beam for pilotless aircrafts is introduced. The article presents justification of the choice of focusing type electromagnetic radiation (EMR) based on the requirements to the wireless power transmission (WPT) system. The features of the EMR focusing on receiving-rectifying antenna (rectenna) installed on movable objects are considered. With...
The paper deals with the antenna system of Vivaldi type for a ground penetrating radar (GPR), which is optimized for using ultrawideband pulse signals of subnanosecond range. Results of development and experimental investigation of characteristics of the antenna and the entire GPR antenna system have experimentally demonstrated the possibility of detection and localization of subsurface cracks in...
The problem of threshold performance improvement of direction finding using estimator bank approach is considered. The modified unitary Root-MUSIC estimator and pseudo-noise resampling are used to form the estimator bank. The classification of roots of the modified unitary Root-MUSIC polynomial based on their proximity to the unit circle is used on the final step of proposed approach.
The most important feature of technical competence is a particular kind of mind that can be called an engineering way of thinking. Higher technical education must be completely imbued with an idea of encouraging students to gain necessary skills and master techniques to do so. The author discusses basic elements of the issue and presents some of the learning strategies developed by him for many years...
This paper is devoted to a novel multi-frequency and bispectrum-based encoding technique designed for radio communication systems. An experimental study of an interference resistance in digital communication is performed using a novel bispectrum-based strategy. Test statistics evaluated in the form of peak values of magnitude bispectrum estimates are proposed for triplet-signals discrimination. Bit...
The paper contains the modeling results of some printed planar antennas, which can be used in devices with the GSM, CDMA, BT, ZeegBee and WiFi communication controllers. Numerical simulation is realized by the method of moments in the software environment FEKO. The results of simulation and experimental verification of the PCB design samples are presented.
One of the basic problems of all mobile communication system, which is transmission of signal via radio channel, is discussed. In urban conditions, this channel is characterized by multipath propagation. As a result, the field at the receiving point is of complex spatial-polarization structure, which reduces the power induced in a receive antenna and, accordingly, efficiency of the entire communication...
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