Browsing by Author "Azrar, Arab"
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Item A 2.3-14 GHz UWB planar octagonal antenna with modified ground plane(Wiley Periodicals, 2013) Bitchikh, M.; Aksas, R.; Azrar, Arab; Kimouche, H.Item Analysis and synthesis of a K-band microstrip patch antenna array(IEEE, 2009) Challal, Mouloud; Azrar, Arab; Dehmas, Mokrane; Recioui, AbdelmadjidItem Application of the FCEL method to a microstrip disk antenna with a parasitic director(2009) Berbar, T. B.; Azrar, Arab; Zerguerras, A.; Aksas, R.The method of finite coupled elementary lines (FCEL) is used in the analysis of a microstrip disk antenna with a larger parasitic director. A closed form expression of the effective radius for the used structure is proposed. The obtained numerical results are compared with published measurements and good agreement is noticedItem Bandwidth improvement of a single-stage distributed amplifier(2010) Amrani, F.; Trabelsi, M.; Aksas, R.; Azrar, ArabThe article discusses the use of bandwidth to improve single-stage distributed amplifier with the use of a Chebyshev polynomial to express the transducer power gain. It states that the conventional distributed amplifiers are formed by artificial transmissions and conventional single-stage distributed amplifier. In addition, the metal semiconductor field effect transistor has gate capacitance of the transistor to improve the bandwidth of the single-stage distributed amplifierItem Beamspace Unitary ESPRIT Parameter Channel Estimation for Pilot Contamination Mitigation(Institute of Electrical and Electronics Engineers Inc., 2018) Smaili, N.; Djeddou, Mustapha; Chafaa, Irched; Azrar, ArabThe main aim of this paper is to resolve a pilot contamination (PC) problem in multicell Massive MIMO system, where the PC is considered as a bottleneck in such systems caused by lack of orthogonality. To address this constrained problem, we propose a new approach based on beamspace unitary (BU) estimation of signal parameters via rotational invariance technique (ESPRIT) for parameter channel estimation. Indeed, the PC mitigation is based on two steps, channels parameter estimation and then reconstruction of desired channel by exploiting the path gains magnitude. The simulation results demonstrate the effectiveness of the proposed approach.Item Characterization of the polarization in the spun fibers(2009) Cherbi, L.; Azrar, Arab; Mehenni, M.; Aksas, R.The polarization mode dispersion (PMD) is a difficult phenomenon to compensate in the optical fiber. Its reduction can be achieved by the spinning process that provokes the rotation of the birefringence axes of the fiber inciting a coupling of its modes that is controlled at the time of its manufacture. In this work, the Jones Matrix Eigen-Analysis method (JME) is used to characterize the spun fibers to evaluate their PMD and to prove that it is distinctly lower than the standards fibers PMD. Furthermore, the differential group delays (DGD) of spun fibers is determined using the photon counting optical time-domain reflectometry (C-OTDR) method. The obtained results are compared with those found in the JME method. It is noted that the two methods yield practically identical values. The determination of the beat length and the spin period of spun fibers are carried out using the polarization-sensitive optical frequency-domain reflectometer (POFDRItem Circuit modeling and EM simulation verification of DGS based Low-Pass filter employing transmission line model along with Microstrip-Slotline transitions(EDP Sciences, 2016) Challal, Mouloud; Dehmas, Mokrane; Azrar, Arab; Aksas, Rabia; Trabelsi, MohamedIn this paper, an equivalent circuit model (ECM) for a defected ground structure (DGS) pattern is proposed and evaluated for designing a compact low-pass filter (LPF). The proposed ECM is based on microstrip lines and microstrip-slotline transitions. Every slotlines of the DGS unit are modeled by ideals transmission lines of characteristic impedance and electrical length. Comparison between full-wave EM and circuit simulations illustrates the validity of the proposed ECMItem Combating multiple access interference in wireless communication systems employing smart antennas(IEEE, 2009) Recioui, Abdelmadjid; Bentarzi, Hamid; Azrar, Arab; Dehmas, Mokrane; Challal, MouloudSmart Antennas constitute a promising technology in wireless communication systems as they mitigate multiple access interference through spatial filtering. One basic building block of smart antennas is the antenna array itself. This latter generates a wide range of aspects that can be the subject of deep investigations namely their geometry, physical parameters, feeding techniques etc... Hence, it is important to investigate whether certain array geometry will enable optimal performance. In this work, the effect of the array geometry choice on the interference rejection capability is investigated. Linear and circular array geometries are considered with mutual coupling between real antenna elements taken into account. Assessment of both geometries is done through a figure of merit that takes into account the rejection capability and radiation characteristics of the arrayItem Compact Down-Conversion mixer design employing a wide and deep Stop-Band DGS-LPF(2016) Challal, Mouloud; Dehmas, Mokrane; Azrar, Arab; Aksas, Rabia; Trabelsi, MohamedThis paper investigates a compact 24-GHz hybrid down-conversion mixer. The proposed mixer is based on a wide and deep stop-band low pass filter, four Schottky diodes, two hybrid couplers and an open stub. The unwanted harmonics are rejected by means of a filter based on three uniforms dumbbell-shaped defected ground structure and a compensated microstrip line. A good conversion loss of 2.19dB, 1-dB compression point of 3-dBm and an LO-to-RF isolation better than 35dB are obtained. The validity of the mixer configuration and the design procedure are confirmed by a comparison between simulation results and measurements data reported in literatureItem Compact microstrip low-pass filter design with ultra-wide reject band using a novel quarter-circle DGS shape(2012) Challal, Mouloud; Boutejdar, A.; Dehmas, Mokrane; Azrar, Arab; Omar, A.A novel quarter-circle defected ground structure shape is introduced in this paper to design and implement an ultra-wide reject band low-pass filter (LPF). Moreover, an equivalent circuit model (ECM) is presented. The proposed LPF has small size and, a low insertion loss and a return loss less than -20 dB. Also, a round -20 dB suppression level ranging from 4 GHz to more than 20 GHz is achieved. The simulated results obtained by ECM and full-wave EM show good agreement with the measured onesItem Compact, low insertion loss and Ultra-Wide rejection bandwidth microstrip Low-Pass filter(2013) Challal, Mouloud; Boutejdar, Ahmed; Dehmas, Mokrane; Azrar, ArabItem Comparative study of three shapes of DGS pattern and design of compact microstrip low-pass and band-pass filters(2011) Challal, Mouloud; Labu, Frederick; Dehmas, Mokrane; Azrar, ArabIn this paper, three types of defected ground structure (DGS) units which are triangular-head (TH), rectangular-head (RH) and U-shape (US) are investigated and their characteristics are compared each other. Further, they are used in the design of low-pass filters (LPF) and band-pass filters (BPF) and the obtained performances are examined. The LPF employing RS-DGS geometry presents the advantages of compact size, low-insertion loss and wide stopband compared to the other filters. It provides a cutoff frequency at 2.5 GHz, a largest rejection band width of 20 dB from 2.98 to 8.76 GHz, a smallest transition region and a smallest sharpness response at the cutoff frequency. The BPF based on RS-DGS has the highest bandwidth (BW) of about 0.74 GHz and the lowest center frequency of 3.24 GHz whereas the other BPFs have BWs less than 0.7 GHzItem Design and analysis of a microstrip patch antenna for medical applications(IEEE, 2017) Grabssi, Wahiba; Izza, Sarah; Azrar, ArabIn this work, a dual band Microstrip patch implantable antenna for biomedical applications has been presented to operate in both Medical Implant Communications Service (MICS) with a range of 402-405 MHz and 2.4-2.5 GHz band chosen among the Industrial Scientific and Medical (ISM). A rectangular antenna has been first simulated to operate in MICS band with dimensions of 179.7 × 228.3 × 1.63 mm, then, a new meandered serpentine shape, with single feed point, has been used in order to lengthen the current path and covers both MICS and ISM bands with new dimensions of 31 × 25 × 1.63 mm printed on dielectric material of 4.3 constantItem Design and optimization of a CPW-fed tri-band patch antenna using genetic algorithms(Applied Computational Electromagnetics Society (ACES), 2015) Fertas, K.; Kimouche, H.; Challal, Mouloud; Aksas, Hammouche; Aksas, R.; Azrar, ArabItem Effect of integrated DGS filters on small slotted round microstrip antenna(Wiley Periodicals, 2013) Oukil, Sofiane; Azrar, Arab; Kimouche, Hocine; Aksas, RabiaItem Effect of oblique projection beamforming on the achievable rate in massive MIMO system(Springer, 2018) Smaili, Nessrine; Djeddou, Mustapha; Ghanem, K.; Azrar, ArabItem An electrically small antenna with integrated DGS filter(Wiley Periodicals, 2013) Oukil, Sofiane; Kimouche, Hocine; Azrar, ArabItem Erratum : new UWB antenna design for wireless communications(Wiley, 2012) Bitchikh, M.; Aksas, R.; Kimouche, H.; Azrar, ArabItem FPGA-based design process of a fuzzy logic controller for a dual-axis sun tracking system(Springer, 2014) Benzekri, Azzouz; Azrar, ArabItem Full‐wave analysis of the broadband circular polarization microstrip patch antenna(Wiley, 2000) Azrar, Arab; Aksas, Rabia; Vander Vorst, Andre
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