Browsing by Author "Lashab, Mohamed"

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    Design of UWB antennas for 5G mobile communications
    (University of Oum El Bouaghi, 2024) Daira, Seyf El Islem; Lashab, Mohamed
    The advent of fifth-generation (5G) mobile communication systems has necessitated a paradigm shift in antenna design, compelling the development of antennas that can simultaneously offer ultra-wideband (UWB) capabilities, miniaturized dimensions, multi- band performance, and high gain. This PhD thesis addresses the complex challenges inherent in designing such advanced antennas for 5G and UWB applications. The research investigates the integration of innovative techniques, including fractal geometries, metamaterials, and advanced methods, to meet the stringent requirements imposed by modern communication networks. The thesis begins with a thorough review of the literature on UWB and 5G antenna design, highlighting the evolution of antenna technologies and identifying key challenges and innovations within these domains. This comprehensive review sets the stage for the research, which focuses on developing novel antenna design that fulfill the demanding specifications of UWB and 5G communication systems. The research first explores a metamaterial-based UWB patch antenna optimized for Sub-6 GHz 5G applications. By integrating Split Ring Resonator (SRR) unit cells and Defective Ground Structures (DGS), the antenna achieves significant improvements in bandwidth, gain, and overall electromagnetic performance, demonstrating the efficacy of metamaterials in enhancing antenna design. The study then presents an FSS unit cell design intended to filter electromagnetic signals across the entire UWB frequency range for filtering and shielding applications. Finally, the research presents a novel design of a UWB antenna using fractal techniques, achieving a broad impedance bandwidth and maintaining high gain across the UWB spectrum using Frequency Selective Surface technique. The fractal-based design effectively miniaturizes the antenna while preserving its performance, addressing a critical challenge in UWB antenna development. L'avènement des systèmes de communication mobile de cinquième génération (5G) a nécessité un changement de paradigme dans la conception des antennes, obligeant au développement d'antennes pouvant offrir simultanément des capacités ultra-larges bande (UWB), des dimensions miniaturisées, des performances multi bandes et un gain élevé. Cette thèse de doctorat aborde les défis complexes inhérents à la conception de telles antennes vancées pour les applications 5G et UWB. La recherche étudie l'intégration de techniques innovantes, notamment des géométries fractales, des métamatériaux et des méthodes avancées, pour répondre aux exigences strictes imposées par les réseaux de communication modernes. La thèse commence par une revue approfondie de la littérature sur la conception des antennes UWB et 5G, soulignant l'évolution des technologies d'antenne et identifiant les principaux défis et innovations dans ces domaines. Cette revue complète ouvre la voie à la recherche, qui se concentre sur le développement d'une nouvelle conception d'antenne qui répond aux spécifications exigeantes des systèmes de communication UWB et 5G. La recherche explore d'abord une antenne patch UWB à base de métamatériaux optimisée pour les applications G Sub-6 GHz. En intégrant des cellules unitaires Split Ring Resonator (SRR) et des structures de masse défectueuses (DGS), l'antenne obtient des améliorations significatives en termes de bande passante, de gain et de performances électromagnétiques globales, démontrant l'efficacité des métamatériaux dans l'amélioration de la conception de l'antenne. L'étude présente ensuite une conception de cellule unitaire FSS destinée à filtrer les signaux électromagnétiques sur toute la gamme de fréquences UWB pour les applications de filtrage et de blindage. Enfin, la recherche présente une nouvelle conception d'une antenne UWB utilisant des techniques fractales, permettant d'obtenir une large bande passante d'impédance et de maintenir un gain élevé sur tout le spectre UWB à l'aide de la technique de surface sélective en fréquence. La conception basée sur les fractales miniaturise fficacement l'antenne tout en préservant ses performances, répondant ainsi à un défi critique dans le développement d'antennes UWB.
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    Electronics, artifical intelligence and new technologies
    (University of Oum El Bouaghi, 2021) Lashab, Mohamed
    The Electronics and New Technologies Laboratory (LENT) is organizing the first international conference on electronics, artificial intelligence and new technologies (ICEAINT'21), this will be held at the University of Larbi Ben M’hidi, Oum El Bouaghi. The conference will cover all the research activities of the laboratory; moreover, the conference will include different axes of electronics, computer science and new technologies likely to interest all researchers in these fields. The ICEAINT'21 aims to bring together academic researchers and industrial scientists to exchange new ideas, original research results and practical development experiences on all aspects dealing with the different themes of the conference.
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    Microwave Sensor for Liquid Mixture Identification based on Metamaterial based on Double Concentric Elliptical Complementary Split Ring Resonator
    (University of Oum El Bouaghi, 2021) Halfaya, Ahmed; Lashab, Mohamed; Salmi, Salah; Soufi Youcef
    In this paper a Microstrip line coupled double concentric elliptical complementary split-ring resonator etched in the ground plane is used to create a sensor. The operating frequency of presented metamaterial sensor is from 1Ghz to 2 Ghz .The sensor is designed and simulated with the commercial software CST Studio Suite . The liquid sample's complicated dielectric permittivity affects the resonance frequency and bandwidth. We can build an empirical link between sensor resonance and sample permittivity using data collected from simulations. the resonance frequency is shifted from 1.50 down to1.49 Ghz. On the basis of variations in the resonance frequency and peak attenuation of the transmission response [ l S21 l max] on resonance the sensor estimates the complex permittivity of a liquid. The proposed sensor is easily to fabricated and reusable resonator.
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    PAPR Reduction in OTFS by modified Similar Raised Cosine mSRC Pulse Shaping
    (University of Oum El Bouaghi, 2021) Benadjina, Nassim; Lashab, Mohamed; Slimani, Djamel
    In this letter, we analyze Peak-to-Average Power Ratio (PAPR) of orthogonal time-frequency space (OTFS) modulation with pulse shaping. We implemented modified similar raised cosine (mSRC) pulse shaping in the OTFS based System and compare it with rectangular and raised cosine (RC) pulse shaping. Simulations results show that the use of mSRC pulse shaping in OTFS based system reduces the PAPR significantly and achieves better performances maintaining BER performance compared to other pulses shaping.