Items of № 3, 2011

The Electrosvyaz Magazine is one of the leading science & technical magazines in Russia.


Using the superdirectivity effect in broadband receiving circular antenna arrays

The article is about broadband receive circularly disposed antenna array (CAA), that have “regular” electric sizes in the upper part of the bandwidth, but becoming electrically small in its lower part. The article describes a method that maximizes the directional gain (DG). Method is frequency invariant, and its use in the lower part of the bandwidth leads to the superdirectivity effect. The chance of degraded susceptibility is discussed in lower part of the bandwidth due to the superdirectivity effect. A method of changing the degree of superdirectivity is shown, which gives a chance for optimization. Calculation methods are described, results are listed. They show the use of superdirective CAA in SW ad lower bandwidths. Key words: CAA, DG, superdirectivity effect, сalculation method.



Earth surface areas having significant impact on the noise temperature of aerial

The noise temperature is one of the most important satellite earth stations’ reflector antennae parameters. It doesn’t depend on atmospheric and Earth surface thermal noise within the frequency band in question, their physical conditions or elevation angle.
Researches have shown that there is substantial influence which the feed’s scattering fields, receiving the thermal emission directly from the soil, have on the noise temperature of the satellite earth stations axisymmetric reflector antennae.
The contributions from these scattering fields are determined by the physical state of the Earth surface, soil moisture and roughness.
In such a situation there is a need to determine the Earth surface area that has significant impact on the amount of this noise temperature contribution.
The article provides an algorithm for determining the boundaries of the Earth surface area which is horizontally flat by Rayleigh and has substantial impact on the contribution to the noise temperature of the satellite earth stations axisymmetric antennae. The article explains different algorithms for determining the boundaries of the areas for both single-dish and two-dish antennae, it also provides calculations results.
Key words: satellite communications, axisymmetric reflector, noise temperature, Earth surface area.


The FRPC FSUE “NPP “Polyot” avionic antenna equipment – from antennas to antennas arrays and fifth generation integrated antenna systems

The article describes an integrated approach to the aviation antenna equipment development, which assumes not only the development but also the installation of the antennas on the objects, mathematic simulation using the latest computer programs, optimization of the radiation characteristics in view of the installation on the object using a scaled model and the object fragments.
The FRPC FSUE “NPP “Polyot” has developed and produced more than 60 antenna devices and systems within 3 kHz to 6 GHz. By their radiation characteristics and external effects the developed and series-produced antennas meet all Air Force overall operational requirements.
Development of phased-array antennas of VHF-UHF1 frequency band is in progress. The application of the phased-array antennas provides the increase of the radio link energy potential in the transmission channels by 5—7 dB and in the reception channels by more than 9 dB.
The article represents an integrated antenna-feeder system developed for the T-50 fifth generation fighter, where each of the antennas is used for several subsystems of the object (communication, navigation, identification and others). The system elements do not project the airframe lines. The application of such antenna reduced the total quantity of antennas on board an aircraft by 25 % and 7-9 times reduced the scattering cross-section of the antenna system.
Key words: communication, navigation, identification and targeting antenna-feeder devices for aircraft, helicopters and unmanned flying vehicles (UFV), aviation radio communication phased-array antennas, integrated antenna-feeder systems (IAFS) on the basis of antenna integrated stealth technology (AIST) intended for the fifth generation fighter.



A mobile automated measuring complex for definition of antenna radiation characteristics

The article describes a mobile automated measuring complex which is easily installed on board a helicopter and allows measuring the electromagnetic field strength in HF, MF, LF and VLF bands, with its horizontal and vertical components being separated, during flight calibration. The measurement results’ processing variants in various coordinate systems are considered in detail.
Key words: electromagnetic field, mobile automated measuring complex, HF, MF, LF and VLF bands.



Simulation of VLF mobile transmitting antenna input parameter

The article is of interest for the developers of mobile transmitting VLF antennas trailed by flying vehicles (aircraft, helicopters, and balloons).
The purpose of work is the development of a wire-greed antenna model, which is designed for calculation of input impedance by the Pocklington’s integral equation method taking into account the configuration of electrically short towing aircraft.
The wire-greed model parameters have been obtained by electrodynamic simulation.
Key words: electromagnetic simulation, integral equation of current distribution, antenna impedance, VLF range.



Frequency characteristics of a compact resonant correction reactivity antenna

This article discusses the frequency characteristics and parameters of small the resonant antenna (SRA) of capacitor type (C-antenna) with patch reactivity. The frequency characteristics of transmitted power and standing wave ratio (SWR) in feeder of the SRA examined. The SRA analyses results are introduced both traditional as well, as new ones, irregularly qualities of antennas of this category.
Key words: small resonant antenna, patch reactivity, gain-frequency characteristics, standing wave ratio (SWR), radiation resistance, transmitted power, bandwidth.


Modelling emission chrasteristic of ultrashort pulse microstrip spiral antennas

Modeling of spectral characteristics and radiation patterns of a single radiator in the form of microstrip logarithmic spiral antenna on a multilayer substrate in a wide frequency band is carried out. Spatial-temporary distributions of radiator fields at its work with ultrashort Gaussian pulses are investigated by spectral methods. The specialized developed program and its interface make it possible to carry out the analysis of radiation fields for different shaped pulses of both separate radiators, and antenna arrays based on them.
Key words: Ultrashort pulses, microstrip logarithmic spiral, multilayer substrate, spectral methods, UWB antennas, spatial-temporary distributions.



Models and methods of studying operation and next generation networks’ design optimization

New models and research methods of operation and next generation networks’ building optimization are represented in the given article.
Key words: NGN, QoS, self-similar traffics.


Computer modeling of microwave telecommunication devices based on the HFSS program

At the presented work, it was reviewed application of computer analysis of microwave electromagnetic field in the HFSS — one of the currently popular computer programs.
Key words: mathematical and graphical modeling, space discretion, linear approximation.


Methodological basics for a hardware model design of enterprise management systems

This paper proposes a method of designing technical means as a hardware component of tools of operative management system.
Key words: hardware, operative management system, technical model.



Basics of design of active adaptive antenna arrays for aeronautical telecommunication systems

Key words: Active Adaptive Antenna Array, Weight coefficients, radiation pattern, radio communication, interference.

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