Authors:messaoud garah, Elhadi Kenane, Fadila Benmeddour Pages: 4 - 13 Abstract: Among the most used power dividers in the field of telecommunications (antenna networks, mobile networks, radar system, satellite communications,military applications and even missile guidance) we can mention the Wilkinson power divider.In the present paper, a dual band Wilkinson power divider with four ways will be designed.In order to investigate the relationship between the physical dimensions of the Wilkinson power divide rwith its characteristics in terms of operational frequency and bandwidth, a parametric study of a Wilkinson power divider will be presented.To design the dual band four-way Wilkinson power divider (WPD), ADS Momentum simulator is used. The simulator uses a genetic algorithm (GA) algorithm to optimize the structure of the proposed WPD.The proposed power divider is developed to achieve dual bands requirements of WLAN applications. To obtain these frequency specifications in the proposed WPD, many transmission lines sections are added. The transmission lines are printed on FR4 (Flame Resistant 4) substrate of dielectric constant εr of3.4 with loss tangent of 0.0023.The proposed circuit exhibits good characteristics at WLAN frequencies (2.45GHz & 5.8 GHZ) in terms of return loss and isolation. PubDate: 2022-02-04 Issue No:Vol. 6, No. 1 (2022)
Authors:Said Abenna, Mohammed Nahid, Hamid Bouyghf Pages: 14 - 25 Abstract: Alcohol is a serious toxic substance that alters brain function by interfering with neuron processes in the central nervous system, leading to mental and behavioral disorders. Alcoholism has serious pathological effects on the liver, immune system, brain, and heart. The diagnosis of alcoholism is important not only because of its impact on individuals and society but also because of the cost to the national health system, as many people around the world suffer from the disease. These diseases can be diagnosed by automatically classifying normal and alcohol electroencephalogram (EEG) signals. Such that this work contains a simple and very fast prediction system. The method uses a bandpass filter to remove all unused signal frequencies, it can be showed in correlation matrices. Then the use of the machine learning algorithms in the classification stage that characterized by its high classification and prediction speed over than 400 and 25500 samples per second respectively, also, the use of optimization algorithms (GA and HHO) can be increased all accuracy values to more than 99.5% when using all electrodes and without importing data decomposition algorithms. To minimize the number of the electrodes and remained good accuracy values, this work uses the Extra-Trees algorithm, such as with only four electrodes the accuracy value remains higher of 99\%. A comparison with other techniques was performed aiming to validate our approach, and it shows great efficiency, simplicity, and instantly. PubDate: 2022-02-04 Issue No:Vol. 6, No. 1 (2022)
Authors:Anne-Carole HONFOGA, Michel DOSSOU, Véronique MOEYAERT Pages: 26 - 37 Abstract: Signal Space Diversity (SSD) technique was adopted in Digital Video Broadcasting-Terrestrial, second generation (DVB-T2) standard ten years ago to increase system performance over fading channels. This technique consists of rotated and cyclic Q-delayed M-Quadrature Amplitude Modulation (QAM) and has been proposed without considering the complexity induced by the demapper. "Genie Aided" demapping algorithm based on iterative demapping has been presented in DVB-T2 and lets this system approach the Shannon limit. Furthermore, this algorithm is not suitable for hardware implementation. Due to the complexity of the hardware implementation algo�rithms, the advantages of this rotated constellation have not been effectively exploited for network deployment. Moreover, receivers provided by manufacturers do not include suitable demappers when this technique is applied. Therefore, several low complexity algorithms have been proposed during the last decade in the scientific literature to reduce the number of metrics and operators used in the demapping process. This paper presents an exhaustive review of demappers proposed for DVB-T2 and all the low complexity demapping algorithms existing up to now in the literature that is suitable for hardware implementation. Details about these algorithms are given in terms of reduction, parameters, performance and percentage of reduction obtained. PubDate: 2022-02-04 Issue No:Vol. 6, No. 1 (2022)
Authors:Amar Mezache, Zakia Terki, Fouad Chebbara Pages: 38 - 45 Abstract: In radar systems, detection performance depends on assumed target and clutter statistical distributions. The probability of detection is shown to be sensitive to the degree of estimation accuracy of clutter levels. In this work, the performances of non-coherent logt-CFAR, zlog(z)-CFAR and Bayesian-CFAR detectors are investigated using both simulated and real data. Three clutter disturbances are considered named log-normal, Weibull and Pareto type II. Based on simulated data, existing CFAR algorithms provide fully CFAR decision rules. From IPIX real data, the dependence of the false alarm probability associated to each detector is studied. With different range resolutions, it is shown that the Bayesian-CFAR algorithm exhibits a small deviation of the false alarm probability. PubDate: 2022-02-04 Issue No:Vol. 6, No. 1 (2022)
Authors:Houcine Oudira, Nora Lakhlef, Christophe Dumond Pages: 46 - 53 Abstract: The paper concerns the problem of monitoring linear antenna arrays using grey wolf optimization method (GWO). When an abnormal event (fault) affects an array of antenna elements, the radiation pattern changes and significant deviation from the desired design pattern can occur. In this paper, reconfiguration of the amplitude and phase distribution of the remaining working elements in a failed array is considered. This latter can improve the side lobe levels (SLL) and also maintain the null position. The main purpose of using the GWO technique is its ease of implementation and a high performance computational technique. To assess the strength of this new scheme, several case studies involving different types of faults were performed. Simulation results clearly have shown the effectiveness of the proposed algorithm to monitor the failure correction of linear antenna arrays. PubDate: 2022-02-04 Issue No:Vol. 6, No. 1 (2022)
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