Publications Scientifiques

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Author: search.filters.author.Azrar, A.

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    Gain improvement of CPW-Fed monopole antenna over dual-band AMC structure
    (IEEE, 2017) Mouhouche, Faiza; Azrar, A.; Dehmas, M.; Djafri, K.
    A CPW rectangular-ring antenna over an Artificial Magnetic Conductor (AMC) is presented in this work. The AMC is designed as a dual-band structure having an array of unit cells and operates at 2.45GHz and 5.20 GHz. A CPW antenna uses this dual-band AMC structures as a back-plane. Performance comparison is carried out with and without the incorporation of AMC. The simulated and measured results show that the combination of the AMC reflector and the antenna provide directional properties at both frequency bands. It has been found that the antenna gain increases by about 5 dB
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    Compact dual-band reject UWB monopole antenna using EBG structures
    (IEEE, 2017) Mouhouche, Faiza; Azrar, A.; Dehmas, Mokrane; Djafri, K.
    In this paper, a compact dual band notched UWB monopole antenna is presented for WiMAX and X-band satellite applications. Dual band rejection characteristics are achieved by engraving the complementary hexagonal spit ring metamaterial on the radiating element and two modified mushrooms-like EBG structure above the ground plane on the vicinity of feed line. The antenna prototype is fabricated and tested. A good agreement between the simulated and measured results. The radiation pattern and time domain of the proposed design are relatively stable
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    Compact dual-band fractal hexagonal ring monopole antenna for RFID and GSM applications
    (wiley, 2018) Djafri, Kahina; Challal, Mouloud; Azrar, A.; Dehmas, Mokrane
    A novel compact dual‐band fractal antenna suitable for radio frequency identification (RFID) and GSM 1800 applications is developed and presented in this paper. This is achieved by adequate combination of three slotted hexagonal fractal rings which resulted in a significantly reduced size structure that can operate in the frequency ranges [0.895‐0.962 GHz] and [1.706‐1.856 GHz] that cover the frequency bands allocated to the intended applications. The proposed antenna has been fabricated and its reflection coefficient measured where a good agreement is observed with the simulated results.
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    Design a Compact UWB Monopole Antenna with Triple Band-Notched Characteristics Using EBG Structures
    (2018) Mouhouche, Faiza; Azrar, A.; Dehmas, Mokrane; Djafri, K.
    in this paper, a compact ultra-wideband (UWB)monopole antenna with triple band-notched characteris-tics is presented. These triple band rejections are pro-duced by inserting the Complementary Co-directionalSplit-Ring Resonator (CC.SRR) on the radiating elementfor WiMAX/WLAN (3.4–3.95 GHz/5.35–5.9 GHz) andElectromagnetic Band Gap (EBG) structure in the vicinityof transmission line for X-band satellite communications(6.7–7.7 GHz). The proposed antenna with a total size of18 × 20.9 × 1.63 mm3has been constructed and tested. Anequivalent RLC circuit model is proposed and investi-gated. The simulated and measured results show thatthe proposed antenna has an impedance bandwidth(VSWR < 2) extanding from 3.05 GHz to 14 GHz with triplenotched bands of [3.3–3.9 GHz], [5.25–5.86 GHz] and [6.7–7.7 GHz]. The triple band notched characteristics and thegood radiation patterns make the proposed antenna agood candidate for the UWB applications
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    A compact superformula based ultra-wideband antenna shape with two notched bands
    (wiley, 2018) Mouhouche, Faiza; Azrar, A.; Dehmas, Mokrane; Djafri, Kahina
    In this paper, a compact superformula ultra‐wideband (UWB) monopole antenna with dual band notches is proposed. The developed structure achieves UWB performance as well as a compact size of 20 × 26 × 1.62 mm3. Furthermore, to avoid interferences with WiMAX and satellite communication systems, dual notched band is obtained by engraving two co‐directional triangular split ring defects on the radiating element. The simulated and measured results show that the proposed antenna has an impedance bandwidth extending from 3.05 to 20 GHz with dual notched bands at [5.15‐5.68 GHz], and [7.15‐7.65 GHz] used in WiMAX and satellite communication, respectively. The proposed design realizes omnidirectional radiation pattern in H‐plane, and a dipole‐like pattern in E‐plane. The antenna exhibits an acceptable gain in the whole UWB range except at notched bands.
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    Analysis of a printed X-Shaped monopole antenna
    (IEEE, 2017) Dehmas, Mokrane; Hamza, A. A.; Challal, Mouloud; Benmahdjoub, I.; Azrar, A.; Djafri, K.; Mouhouche, Faiza
    This paper presents a study of a printed X-shaped monopole antenna. The analysis has started from considering a strip fed conventional single band Rectangular Microstrip Antenna (RMSA) resonating at 2.45 GHz commonly used in WLAN applications. The antenna has been transformed to a monopole structure that has yielded a larger bandwidth. In the second part, triangular slots were introduced to the RMSA to obtain an X-shaped antenna and their effects were investigated. An X-shaped monopole structure presenting a bandwidth of 3.39 GHz (1.96-5.35 GHz) has been obtained. The analysis suggested a possibility of performing size reduction. This part resulted in a final X-shaped monopole printed structure with an enhanced bandwidth of 6.2 GHz (1.8-8.0 GHz) and a significant external size reduction of 55.48 %. The final antenna which can be used in various applications (WLAN, Wi-Fi, Wi-Max, LTE 4G, surveillance systems, medical imaging, etc.) has been fabricated and its reflection coefficient measured. Good agreement was noticed between the simulated and measured results.
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    Compact dual band slotted triangular monopole antenna for RFID applications
    (Wiley, 2017) Dehmas, Mokrane; Azrar, A.; Mouhouche, Faiza; Djafri, K.; Challal, Mouloud
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    Dual band monopole antenna using metamaterials
    (IEEE, 2017) Mouhouche, Faiza; Azrar, A.; Djafri, K.
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    Wide stopband microstrip bandpass filter based on a compact slotted ground structure
    (Polish Academy of Sciences, 2015) Challal, Mouloud; Dehmas, Mokrane; Azrar, A.; Aksas, R.; Trabelsi, M.
    A new concept for implementing a bandpass filter by employing a discontinuity in the feed microstrip line in the upper layer and modified dumbbell-shaped slots etched in the ground plane is proposed. The effect of the slot area on the bandpass filter performance is examined. The proposed bandpass filter showed wide stopband and low insertion loss. To further verify the new concept, the structure is implemented and the measurement results are found to be in good agreement with the simulation ones. The proposed structure can be used in various microwave circuits
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    Microstrip design of low noise amplifier for application in narrowband and wideband
    (IEEE, 2008) Challal, Mouloud; Azrar, A.; Bentarzi, Hamid; Janvier, D.V
    A low-noise amplifier (LNA) is presented in this paper. The LNA is designed and optimized for narrowband and wideband operations along with minimum noise figure around 24 GHz (K-Band). The designed LNA employs microstrip input and output matching networks; it achieves a noise figure of 3.85 dB and 10.55 dB of gain along with 10.27 dB and 17.83 dB of input and output return losses, respectively for its narrow band. Where as for its wideband it accomplishes a gain of 6.5 dB with ±0.3 dB flatness from 24 to 25.25 GHz wideband frequency range, the noise figure obtained for the presented LNA is in close proximity to the minimum noise figure over 23 - 24.5 GHz frequency range