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The method of constructing the antenna device for the RASS with passive spot location was considered. These systems were designed for meteorological support of the atmosphere environmental monitoring.
A possibility for efficient use of radio-frequency spectrum and of corresponding increase in productivity of mobile communication system with space-time multiple access obtained by use of multibeam antenna of base station is considered.
Sensory network properties of self-organization and self-recovery are complemented with the property of spatial selectivity possess wider abilities. They facilitate search and positioning of an interacting station and promote the increase in the range of coverage.
The analysis of spatial processing effectiveness for the two variants of smart-antenna is studied: multi-beam antenna array with beam switching and adaptive antenna array. Efficiency is measured by the output signal-to-noise ratio. The boundary values of efficiency for arbitrary noise conditions are set. The recommendations for practical application are formulated.
In December, 2014, it was 115 years from the date Emile Guarini Foresio invented directed antennas for a radio relay repeater. This paper gives the brief history of antennas for relay stations.
The results of an experimental study of patterns of the three-band feed for a small VLBI2010 compatible radio telescope reflector antenna are presented. Differences of the behavior of experimental three-band feed patterns and requirements specification for feed-prototype [1] are brought to light. A new engineering solution of the three-band feed unit has been suggested.
The problem of creation of antenna feeder devices (AFD) for telemetric systems of launchers for commercial starts of spacecrafts on different ascent trajectories is considered. The principles of AFD creation on the basis of use of the controlled antenna arrays of meter and decimeter frequency bands and features of switching antennas are stated.
Numerical simulation results for multimodule antenna array in form of linear array consisting of rectangular subarrays (modules) are given. It's shown that grating lobes appear in the array factor if the amplitude distribution within a module and within a system of modules are independent from each other. The dependence of grating lobes level on amplitude distribution parameters is considered.
Radio astronomy deals with the weakest signals received by a radio electronic device, and, as a result, it is very complicated problem to maintain appropriate SNR while transferring signal from the antenna output to receiver's input. In this paper, a system for delivering the radio astronomical signals from dipole terminals to ADC input of Giant Ukrainian Radio Telescope (GURT) is described. Examples...
The paper examines the solution of scientific problem on determining the information reliability of digital channel of troposphere communication with an adaptive antenna, when signals at the output of the adaptive antenna and adaptive receiver are controlled simultaneously and compared with the fixation of the conditions of existence of informational redundancy of the channel, that automatically specifies...
The problem of the field diffraction of radial electrical current ring on a spiral conductive sphere with a hole has been solved. The current ring is placed outside the supplement of a sphere with a hole to a closed hollow sphere. The method of operator semi-inversion of the problem, the method of separation of variables in the spherical system coordinates and of the solution of Abel integral equations...
The problem of interaction of a single strip with a plane semi-infinite grating is considered. It is reduced to a system of operator equations relatively spectral functions of scattered field. Field scattered by the structure may be represented as a superposition of fields with discrete (plane waves) and continuous spectrum (cylindrical wave). So, the kernel-function of the reflection operator may...
This paper considers creation of an anisotropic cloak that provides mimicry of an elliptic cylinder, covered by it, so that for an external observer this elliptical cylinder looks like circular. The technique of designing such mimicry cloaks using the transformation optics approach is presented. We provided a numerical simulation of such a cloak and evaluated its performance.
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...
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...
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...
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 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.
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