Browsing by Author "Dehmas, Mokrane"

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Analysis and synthesis of a K-band microstrip patch antenna array
(IEEE, 2009) Challal, Mouloud; Azrar, Arab; Dehmas, Mokrane; Recioui, Abdelmadjid
Analysis of a fractal Ultra Wide Band monopole antenna with reconfigurable notches
(2021) Abbad, Mohammed; Habtiche, Nabil; Dehmas, Mokrane
This work describes the design and analysis of a fractal Ultra-Wide Band (UWB) coplanar fractal antenna with triple reconfigurable notch rejection bands. The investigation considers three successive configurations: coplanar monopole circular UWB antenna – Fractal coplanar monopole UWB band antenna with improved bandwidth – Slotted UWB structurewith reconfigurable notches. Reconfigurability is achieved by opening / short-circuiting appropriate slots to select the rejected band(s). This study has ended with three reconfigurable notches bands covering the frequency bands: [4.50 ?????? , 5.35 ??????] , [6.30 ?????? , 7.15 ??????] and [8.15 ?????? , 8.60 ??????] including Wi-Max and WLAN applications and X band. The Developed structure was printed on a 21x25x1.63 mm 3 glass epoxy FR-4 substrate. The input reflection coefficient has been measured where an agreement was observed betweensimulated and experimental results. The simulations concerning the input reflection coefficients, current distributions and radiation patterns were carried out using the CST Microwave Studio.
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.
Analysis of a reconfigurable multi-Band monopole antenna
(2021) Gharbi, Abdelhamid; Belgacem, Abdelmalek; Dehmas, Mokrane
This work deals with analysis of a monopole and frequency reconfigurable E-shape patch antenna using FR-4 substrate. The first step concerns modification of a published reconfigurable antenna due to difference in physical properties of the used substrate and the one at our disposal. These appropriate modifications have been performed on the antenna dimensions and on the stripline width so that the modified structure fits the original antenna band characteristics. In the second step, which concerns the main contribution of this work, a parametric analysis of the first structure focusing on the slot positions is achieved. The analysis ended up with nine (9) antenna geometrical configurations each one operating in four (4) reconfigurable modes. These antennas fulfill and satisfy various applications. One of these antenna configurations -operating in one single-band and three dual band reconfigurable modes- has been considered for further analysis. Prototypes of the modified original antenna as well as the one selected in the second part have been fabricated and their reflection coefficients in open switch positions mode measured where good agreements with simulated results have been obtained.
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, Mohamed
In 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 ECM
Combating multiple access interference in wireless communication systems employing smart antennas
(IEEE, 2009) Recioui, Abdelmadjid; Bentarzi, Hamid; Azrar, Arab; Dehmas, Mokrane; Challal, Mouloud
Smart 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 array
A compact ACS-fed tri-band microstrip monopole antenna for WLAN/WiMAX applications
(Advanced Electromagnetics, 2018) Djafri, Kahina; Challal, Mouloud; Dehmas, Mokrane; Mouhouche, Faiza; Aksas, Rabia
This paper proposes a novel small asymmetric coplanar strip (ACS) fed tri-band monopole antenna for WLAN and WiMAX applications. To tune and create multiple resonant frequencies, the exciting strip of monopole antenna is connected to two different arms which are a J-shaped directed toward the asymmetric ground plane and an open stub. The proposed monopole antenna with a total size of 14.6 x17.5 mm2 is fabricated and tested. The measured results indicate that the antenna has impedance bandwidths for 10-dB return loss reach about 500 MHz (2.01-2.52 GHz), 230 MHz (3.48-3.71 GHz) and 1.2GHz (5.59-6.72 GHz) which cover widely the 2.4/5.8 GHz WLAN bands and the 3.5GHz WiMAX band. The simulated radiation patterns of the proposed antenna at the three resonant frequencies have a dipole-like radiation pattern in both E-and H-Planes. The compact size, the simple structure and good radiation performances of the proposed antenna makes it well-suited forthe intended applications
A compact double-inverted Ω-shaped dual-band patch antenna for WLAN/WiMAX applications
(Frequenz : journal of RF-engineering and telecommunications, 2022) Djafri, Kahina; Mouhouche, Faiza; Dehmas, Mokrane; Challal, Mouloud
In this study, a new compact dual-band antenna with overall size of 11 × 14.46 × 1.6 mm3 has been designed, fabricated and tested. The proposed antenna consists of two inverted Ω-shaped strips loaded with two different comb structures. The fist comb of six elements connected to the first Ω-shaped radiating branch is used to decrease the second band lower cut-off frequency and cover the intended WLAN and WiMAX applications. In order to cover the 2.45 GHz WLAN band and further reduce the antenna dimensions, a second comb structure of 14 elements is attached to the upper radiating branch. The fabricated antenna covers the frequency bands from 2.42 to 2.6 GHz and from 4.25 to 6.77 GHz with a reflection coefficient of |S 11| ≤ −10 dB. The antenna shows an omnidirectional radiation pattern in the H-plane and a monopole-like radiation pattern in the E-plane. The measured results agree well with the simulated ones which indicate that the proposed antenna is suitable to be used in the WLAN/WiMAX applications
Compact Down-Conversion mixer design employing a wide and deep Stop-Band DGS-LPF
(2016) Challal, Mouloud; Dehmas, Mokrane; Azrar, Arab; Aksas, Rabia; Trabelsi, Mohamed
This 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 literature
Compact dual band slotted triangular monopole antenna for RFID applications
(Wiley, 2017) Dehmas, Mokrane; Azrar, A.; Mouhouche, Faiza; Djafri, K.; Challal, Mouloud
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.
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
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 ones
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.
Compact, low insertion loss and Ultra-Wide rejection bandwidth microstrip Low-Pass filter
(2013) Challal, Mouloud; Boutejdar, Ahmed; Dehmas, Mokrane; Azrar, Arab
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, Arab
In 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 GHz
Contribution to the analysis of small microstrip patch antennas
(2020) Dehmas, Mokrane
In this thesis, three compact microstrip antennas based on the defected microstrip (DMS) and the shorting post insertion techniques are developed. The first is a single-band operating in the radar 3 GHz frequency. It achieves a miniaturization ratio of around 77 % compared to a conventional rectangular structure. The second is a dual-band monopole covering UHF radio frequency identification bands. A size reduction of nearly 44 % is achieved compared to a reported structure. The third is a multi-band antenna operating in six frequency bands suitable for different applications involving commercial ones. A size reduction of nearly 60 % with respect to the original antenna has been obtained. Prototypes of the proposed antennas have been fabricated and their input reflection coefficients
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
Determination of potential profile in planar electronic structures using a semi-analytical technique
(2010) Bourdoucen, H.; Dehmas, Mokrane; Yallaoui, E.-B.
Extension of the method of lines for the analysis of semiconductor devices
(1996) Dehmas, Mokrane
The method of lines is semianalytique for numerical simulation of partial differential equations. Although the various advantages of this method such as simplicity in concept, efficiency, and reduced computer memory space and requirements, its application is still confined in the field of integrated microwave structures...