Antenna Arrays Focused on Broadband Signals, Journal of Telecommunications and Information Technology, 2016, nr 2

Broadband and ultra-wideband signals are increasingly used in modern radio systems. Traditional performance of evaluation antennas operating with narrowband signals are not always adequately reflect the characteristics of broadband antennas, at least in view of the frequency dependence of the antenna pattern. Accounting for broadband signals the antennas becomes important in the low-frequency range of the spectrum. Systems using these types of signals may include control of the atmosphere and measuring its frequency-selective properties in the range meter and decameter wavelengths. Possibility of spatial selection based on focusing of broadband signals in this case promises to implement a number of additional features. Therefore, it is important to evaluate the properties of antennas based on the spectral content of the signal, as well as taking into account the ways of its processing in the receiving equipment. Consideration features of functioning the antenna array, focused on broadband signal is devoted to this article

Radio Photonic Systems for Measurement of Instantaneous Radio Frequency with Amplitude-phase Modulation of Optical Carrier, Journal of Telecommunications and Information Technology, 2016, nr 2

In this article questions related to the development instantaneous radio frequency measurement system based on application in them original ways of the amplitude-phase modulation transformation of single-frequency optical carrier by a radio signal in symmetric two-frequency and measuring “frequency-amplitude” transformation in fiber Bragg grating with special profile are considered. Such systems have broad prospects for use in telecommunications, military systems and for environmental monitoring

Random incoherent antenna arrays focused in the near field zone

In this article we have examined the properties of incoherent arrays, focused in the near field zone, developed a mathematical model for calculating the parameters of different kind of incoherent antenna arrays, such as size of focusing area, dependence of focus area on pulse duration

Changes in Heavy Oil Saturates and Aromatics in the Presence of Microwave Radiation and Iron-Based Nanoparticles

Our knowledge of electromagnetic heating’s effect on heavy oil upgrading is largely based on very limited data. The aim of the present research was thus to study in detail the effect of microwave exposure in the absence and presence of nanosized magnetite on the composition of heavy oil. The obtained data reveal that the use of nanosized magnetite improves not only microwave radiation application as a result of its absorption and release of thermal energy but also that these nanoparticles have a catalytic ability to break carbon–heteroatom bonds in the composition of resins and asphaltene molecules. In fact, the overall reduction in asphaltenes or resins does not always adequately describe very important changes in asphaltene composition. Even a small fraction of broken carbon–heteroatom bonds can lead to an increase in the mobility of asphaltenes. Moreover, this study has shed light on the important evidence for asphaltenes’ transformation, which was found to be the formation of light aromatic compounds, such as alkylbenzenes, naphthalenes and phenanthrenes. These compounds were fixed in the composition of the aromatic fraction. We believe that these compounds could be the fragments obtained from asphaltenes’ degradation. The evidence from this study points toward the idea that asphaltenes’ destruction is crucial for increasing oil mobility in the reservoir rock during its thermal stimulation

Changes in Heavy Oil Saturates and Aromatics in the Presence of Microwave Radiation and Iron-Based Nanoparticles

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