Institute of Electron Technology
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Experimental Analysis of a Directive Antenna with a 3D-EBG Superstrate, Journal of Telecommunications and Information Technology, 2017, nr 3
Get PDFA three-dimensional electromagnetic crystal is employed as a directivity-enhancing superstrate for planar antennas. The crystal is a woodpile made of alumina rods. In a shielded anechoic chamber, the performance of a patch antenna covered with the woodpile is measured. The superstrate is positioned at different distances from the antenna and its orientation is varied in the 8–12 GHz frequency range. The return loss, gain and radiation pattern in the E- and H-planes are measured. The electromagnetic behavior of Fabry-Perot cavities with woodpile mirrors, equivalent to the compound radiator, is also studied. The main effect of the crystal on the antenna performance is an enhancement of about 10 dB in maximum gain. A rather complete series of experiments is presented, highlighting the role of the periodic structure in the directivity enhancement and allowing a deeper understanding of the electromagnetic phenomena involved in EBG resonator antennas. Benefits and disadvantages of this kind of antennas are discussed and ideas for future research are given
Data Fixing Algorithm in Radiosonde Monitoring Process, Journal of Telecommunications and Information Technology, 2017, nr 1
Get PDFEarth surface monitoring can give information that may be used in complex analysis of the air conditions, temperature, humidity etc. Data from a vertical profile of the atmosphere is also essential for accurate thunderstorm forecasting. That data is collected by radiosondes – telemetry instruments carried into the atmosphere usually by balloons. Sometimes, due to the hostile conditions of upper troposphere, incorrect data can be generated by radiosonde sensors. In this paper, a new algorithm is developed for fixing the incorrect data, i.e. missing or out of specific range values. The proposed algorithm was tested both on benchmarks and real data generated by radiosondes. About 70% of significantly damaged test data volume was recovered. Up to 100% of real data was fixed
SPOT-GPR: A Freeware Toolfor Target Detection and Localizationin GPR Data Developedwithin the COST Action TU1208, Journal of Telecommunications and Information Technology, 2017, nr 3
Get PDFSPOT-GPR (release 1.0) is a new freeware tool implementing an innovative Sub-Array Processing method, for the analysis of Ground-Penetrating Radar (GPR) data with the main purposes of detecting and localizing targets. The software is implemented in Matlab, it has a graphical user interface and a short manual. This work is the outcome of a series of three Short-Term Scientific Missions (STSMs) funded by European COoperation in Science and Technology (COST) and carried out in the framework of the COST Action TU1208 “Civil Engineering Applications of Ground Penetrating Radar” (www.GPRadar.eu). The input of the software is a GPR radargram (B-scan). The radargram is partitioned in subradargrams, composed of a few traces (A-scans) each. The multi-frequency information enclosed in each trace is exploited and a set of dominant Directions of Arrival (DoA) of the electromagnetic field is calculated for each sub-radargram. The estimated angles are triangulated, obtaining a pattern of crossings that are condensed around target locations. Such pattern is filtered, in order to remove a noisy background of unwanted crossings, and is then processed by applying a statistical procedure. Finally, the targets are detected and their positions are predicted. For DoA estimation, the MUltiple SIgnal Classification (MUSIC) algorithm is employed, in combination with the matched filter technique. To the best of our knowledge, this is the first time the matched filter technique is used for the processing of GPR data. The software has been tested on GPR synthetic radargrams, calculated by using the finite-difference time-domain simulator gprMax, with very good results
A New CPW-fed Patch Antenna for UWB Applications, Journal of Telecommunications and Information Technology, 2017, nr 2
Get PDFIn this paper, the design and analysis of a compact size coplanar waveguide (CPW)-fed antenna for ultrawideband (UWB) applications is presented. The antenna has a compact size of 20×20×1.1 .5 .mm and provides a good impedance matching over the entire bandwidth of 3.2–14.3 GHz. The characteristics parameters, i.e. return loss, VSWR and radiation pattern, are analyzed using HFSS 11.0 software
Mobile Cloud for Parallel and Distributed Green Computing, Journal of Telecommunications and Information Technology, 2017, nr 4
Get PDFMobile Computing and Mobile Cloud Computing are the areas where intensive research is observed. The “mobility” landscape (devices, technologies, apps, etc.) evolves so fast that definitions and taxonomies do not catch up with so dynamic changes and there is still an ambiguity in definitions and common understanding of basic ideas and models. This research focuses on Mobile Cloud understood as parallel and distributed system consisting of a collection of interconnected (and virtualized) mobile devices dynamically provisioned and presented as one unified computing resource. This paper focuses on the mobile green computing cloud applied for parallel and distributed computations and consisting of outdated, abandoned or no longer needed smartphones being able to set up a powerful computing cluster. Besides showing the general idea and background, an actual computing cluster is constructed and its scalability and efficiency is checked versus the results obtained from the virtualized set of smartphones. All the experiments are performed using a dedicated software framework constructed in order to leverage the nolonger-needed smartphones, creating a computing cloud
Battery Available Capacity Meter Built into an AC/DC Telecom Power Supply System, Journal of Telecommunications and Information Technology, 2017, nr 2
Get PDFThe article describes the results of testing a Benning AC/DC power supply, with integrated NIT TBA-ST meter. Such integration enables accurate and energy-efficient measurements of available capacity of individual 48-voltage VRLA/AGM batteries with remote management possibilities. The full compliance with the requirements for telecommunication power systems, the great functionality, upgrade ability, immunity to user errors and the high accuracy of capacity and voltage measurement of battery monoblocks of proposed solution are presented
The Optimum-efficiency Beam Multiplier for an Arbitrary Number of Output Beams and Power Distribution, Journal of Telecommunications and Information Technology, 2017, nr 3
Get PDFThis paper deals with phase gratings working in the paraxial domain. The profile of the optimum-efficiency beam multiplier with an arbitrary number of output diffraction orders is derived in an analytic form by exploiting methods from the calculus of variation. The output beams may be equi-intense or with arbitrary distribution of power. Numerical examples are given for different values of the number of output beams
Modeling of Quality of Experience in No-Reference Model, Journal of Telecommunications and Information Technology, 2017, nr 2
Get PDFThe key objective of no-reference (NR) visual metrics is to predict the end-user experience concerning remotely delivered video content. Rapidly increasing demand for easily accessible, high quality video material makes it crucial for service providers to test the user experience without the need for comparison with reference material. Nevertheless, the QoE measurement is not enough. The information about the source or error is very important as well. Therefore, the described system is based on calculating numerous different NR indicators, which are combined to provide the overall quality score. In this paper, more quality indicators than are used in the QoE calculation are described, since some of them detect specific errors. Such specific errors are dificult to include in a global QoE model but are important from the operation point of view
The New Metric and the New Software Tool for Determining QoS in the Short Messages Service in Mobile Networks, Journal of Telecommunications and Information Technology, 2017, nr 2
Get PDFWith traveling professions and nomadic lifestyles on the increase there is a growing need for comprehensive mobile networking within the Next Generation Network, and the security, reliability and technical independency of the Short Message Service (SMS) is becoming more and more indispensable for business processes. Since competitiveness goes hand-in-hand with this business capability, and methods to determine the quality of this service are becoming equally indispensable. This paper presents possible methods to evaluate the “Completion Rate of SMS” and “End-to-End Delivery Time” and combinations of them (new metric in this paper). A software tool, QoSCalc(SMS), has been developed in collaboration with the authors in order to verify whether service providers are abiding by the Service Level Agreements. The tool has been tested in a real measurement environment and the results are presented graphically here and interpreted
Mitigation of Scintillation Effects in WDM FSO System using Multibeam Technique, Journal of Telecommunications and Information Technology, 2017, nr 2
Get PDFFree Space Optical communication (FSO) has engrossed a large section of researchers in recent times due to its wide bandwidth, effortless deployment and immune links making it appropriate for communication purposes. This wireless optical technique requires clear and non-turbulent atmospheric conditions for efficient transmission. In this paper, authors aim at reducing the effect of turbulent atmospheric conditions like scintillation effect on FSO. Multibeam technique, which uses spatially diverse transmitters for transmission, has been used for increasing the achievable link distance of the FSO system. Parameters like quality factor and bit error rate have been used to check the received signal quality