Browsing by Author "Kendil, Djamel"

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A Bandpass Filter with Triple-Narrow Notch Bands Based on Metamaterials SRR Configurations for UWB Applications
(nternational Academy of Microwave and Optical Technology (IAMOT), 2024) Aissioui, Mohamed; Kendil, Djamel; Fertas, Khelil; Fertas, Fouad
This paper presents a bandpass filter (BPF) with three narrow notched bands designed for ultra-wideband (UWB) applications. Initially, a basic UWB BPF is designed using a microstrip multimode resonator (MMR) with an open stepped impedance stub loaded at its center. Following that, the Split-Ring Resonator (SRR) is used to generate a triple narrow notched band, allowing undesired signals to be rejected. The frequency range is 2.81 GHz to 10.2 GHz. Beyond this range, there is a strong rejection. Notably, three narrowly notched bands at 5.29, 5.83, and 7.99 GHz are used to achieve in-band interference cancellation, with - 3dB fractional bandwidths of 2.64%, 2.91%, and 1.77%, and rejection levels of -17.15 dB, -11.65 dB, and -11.56 dB, respectively. This filter simultaneously has three main advantages: it is simple, rejects unwanted signals within the bandwidth without affecting the adjacent signals, and achieved high selectivity, the simulation and measurement results show a good agreement, demonstrating effective filtering performance, with a compact dimension of 25.9 x 13.7 mm2.
Physical properties of thin films of (α-Fe2O3) aluminum doped by spray pyrolysis methods
(S.C. Virtual Company of Phisics S.R.L, 2023) Chibani, A.; Kendil, Djamel; Benhaoua, B.; Kemerchou, I.; Bekkar, D.
This work aims to study the effect of doping on α-Fe2O3 properties. For this, we elaborated thin layers of pure α-Fe2O3, and aluminum doped with spray pyrolysis method. The structural, morphological, and optical properties of the prepared films form different percentages: 2%, 4%, 6%, 8%and 10% were examined using X-ray diffraction (XRD), FT-IR, and UV-Vis, respectively. Structural characterization from X-ray diffractograms confirmed the formation of α-Fe2O3, it has a rhombohedral structure with strong orientation preferential according to a plane (110) and displacement of the diffraction angles towards large values when the doping rate increases. Studies of transmittance spectra in UV-visible range 550-850 nm, showed high transparency of thin layers elaborated and the increase in direct band-gap energy from 2.59 to 2.78 eV. These characteristics are considered important in all applications
Students misconceptions about light in Algeria
(2009) Blizak, Meriem Djanette; Chafiqi, Fouad; Kendil, Djamel
Physics education research has shown that students have difficulties in learning essential optics concepts. Therefore, in this present work we deal with student’s conceptions in geometrical optics field. Our objective is to show the Algerian students misconceptions. We proposed to 246 students in first year university (aged 18–21) a closed questionnaire where most of its questions were already used by other researchers. The misunderstandings identified were compared with those in literature. The results show that our students have the same misconceptions, related to the propagation of the light, the vision, the refraction and the reflexion, as the students in other countries (Andersson, Çiğdem ŞAHİN, Galili, Goldberg, Viennot,…). We investigate new students “misconception” concerning the propagation of the light in the vacuum
Thermal analysis and experimental design of PVDF-trfe-based pyroelectric sensors for infrared applications
(Elsevier, 2025) Behloul, Mohamed; Bousbiat, Essaid; Yamani, Dalila; Bouddou, Riyadh; Derguini, Nour Eddine; Salau, Ayodeji Olalekan; Kendil, Djamel; Adiche, Sarra
In this paper, the design, analysis, and improvement of a copolymer polyvinylidene fluoride-trifluoro ethylene PVDF-TrFE pyroelectric sensor for infrared detection was investigated. The sensor architecture comprises a multilayer structure consisting of a PVDF-TrFE active layer, a 2 μm air gap for thermal insulation, and a silicon substrate. The finite element method (FEM) and analytical models were then used to analyze the specific parameters determining the sensor's performance. The results show a very high level of correlation between the two methods, with the FEM simulation showing an average error of less than 3 % compared with the analytical techniques. In the optimization process, it was also found that etching a silicon substrate, in particular, improves the device's ability to insulate itself from heat, resulting in a 25 % increase in voltage sensitivity. Further electrical characterization was also carried out using the lock-in technique to determine the sensor's efficiency under different lighting conditions, thus evaluating its functionality as an optoelectrical device. The results confirmed a residual polarization of 9.4 μC/cm2 and a coercive field strength of 80 MV/m for the thermal optimization approach. In addition, the results also revealed that the 30 μm-thick PVDF-TrFE layers produced the highest pyroelectric efficiency, with a yield of 45 μC/m2-K. It was also found that incorporating a 2 μm air gap increased the current response by around 18 %, underlining the role of thermals, highlighting the efficiency of our design, and the contributions of each layer to the sensor performance
What thinks the university's students about propagation of light in the vacuum?
(2013) Blizak, Meriem Djanette; Chafiqi, Fouad; Kendil, Djamel
This study aims to study the conceptions of university students related to the notion of propagation of light in a vacuum. In order to fulfill our aim, a case study research method was used in the study, whose sample consisted of 321 Algerian undergraduates in different levels at science faculty (before and after the optics courses). The data were collected through a test comprising three questions. The results have indicated two students’ misconceptions concerning propagation of light in vacuum. The first one is that the light does not propagate in a vacuum. The second is that the light propagates according the horizontal direction (new misconception). The possible origins of these misconceptions are discussed and suggestions for how to prevent them are given. Also, our results suggest that university students who had a higher level of physics knowledge than their counterparts who studied only geometrical optics, they still held of the same misconceptions. Formal or traditional teaching seems helpless to facing these misconceptions