Browsing by Author "Challal, Mouloud"

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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 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.
Band-notched ultra-wideband bandpass filter design using multiple-mode resonator and stepped impedance stub loaded
(IEEE, 2017) Louazene, Hassiba; Challal, Mouloud; Boulakroune, M'Hamed
A novel ultra-wideband (UWB) bandpass filter (BPF) with notched band is proposed in this paper. The filter is consisting of two symmetrical multiple-mode resonators (MMRs) connected to quarter-wavelength interdigital lines. This filter provides, in the passband, an insertion loss of 0.19 dB and a return loss greater than 22.6 dB. Furthermore, the filter occupies an area of 11.54 × 3.11 mm 2 . In this filter design, besides obtaining a uniform in-band transmission response, a notch band centered roughly 5.2 GHz is created by modifying one of two arms in the coupled-line sections. The simulation results are in satisfactory agreement with the measurement ones reported elsewhere. The proposed UWB-BPF presents good performance in terms of insertion loss, return loss, fractional bandwidth and compact size than those reported in the literature
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
Compact CPW-fed Antenna with Controllable WLAN Band-rejection for Microwave Imaging
(Advanced Electromagnetics, 2024) Mokhtari, Mokhtar; Oussaid, Rachid; Mansoul, Ali; Challal, Mouloud
This work presents the design and experimental validation of a compact frequency-reconfigurable coplanar waveguide (CPW)-fed ultra-wideband (UWB) antenna for application in microwave imaging systems with a capability to switch between UWB modes, with and without WLAN band-notched features. The suggested topology and design process are used to achieve an enhancement in the bandwidth using T-shaped slots between the feedline and the ground plane of the antenna, whereas the WLAN band is rejected using an open loop resonator (OLR) placed on the antenna backside. Switching between UWB with and without WLAN band-notched modes is performed using a single PIN diode. The simulation results corroborate well with the experimental data and clearly show an interesting frequency reconfigurable behavior for use in microwave imaging applications. The antenna performance simulation and analysis model is presented for breast tumor detection.
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.
A Compact Dual-Band Planar Monopole AntennaUsing Fractal Rings and A Y-Shaped FeedingTransmission Line
(DE GRUYTER, 2018) Djafri, Kahina; Challal, Mouloud; Romeu, Jordi
This paper presents a novel design approach ofa compact dual-band monopole antenna with an overallsize of 18.9x13x1.6mm3. The proposed antenna is com-posed of a fractal ring shaped patch fed by a Y-shapedtransmission line on the top side of the substrate and asecond fractal ring along with a U-shaped ground planeon the bottom side. The second fractal ring, identical tothe radiating ring, is loaded and a rectangular slot isetched at the top side of the ground plane respectively,to achieve dual-band characteristic and improve theimpedance matching. The effect of standard ground-plane (SGP) of a laptop computer is incorporated in thedesign; the antenna is mounted on a SGP in order toinvestigate its performance. The antenna covers widelythe frequency bands of the WLAN 2.4 GHz (2.2–2.52 GHz)and WiMAX 3.5 GHz (3.32–4.35 GHz), and exhibits anomnidirectional radiation pattern in the H-plane and amonopole like radiation pattern in the E-plane. A goodagreement between the simulated and measured resultsindicates that the proposed dual-band antenna design issuitable for WLAN/WiMAX applications.
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 Slot-Antenna with Tunable-Frequency for WLAN,WiMAX, LTE, and X-Band Applications
(2020) Fertas, Fouad; Challal, Mouloud; Fertas, Khelil
In this paper, a new monopole compact antenna with tunable frequency fed by a coplanarwaveguide (CPW) for WiMAX, WLAN, LTE bands, and X-band satellite communication system ispresented. This is achieved by adequate combination of a new radiating patch element along with slotsand switches. The simulation and measurement results show that depending on ON/OFF states, theproposed reconfigurable antenna, printed on an FR4 substrate, can operate in four applicable frequencybands, i.e., [2.37–2.75 GHz], [3.15–4.08 GHz], [4.48–5.92 GHz], and [6.69–8.31 GHz]. Very interestingresults for the reflection coefficient, current distribution, and radiation pattern of the antenna arepresented and discussed. The measured results are in good agreement with the simulated ones
Compact UWB BPF with notch-band using SIR and DGS
(Inderscience, 2018) Louazene, Hassiba; Challal, Mouloud; Boulakroune, M'hamed
Compact UWB monopole antenna with WiMAX/ITU band notch characteristics
(IEEE, 2017) Guichi, Fella; Challal, Mouloud
A compact ultra wideband (UWB) antenna with dual band-notched characteristics is proposed and investigated in this article. The antenna is composed of a V-shaped patch with a stair case defect fed by a 50 Ohm microstrip line and a semicircular defected ground plane printed, respectively, on the top and bottom layer of the substrate. The dual band-notch function at WiMAX (3.17-3.85 GHz) and ITU (7.9-9.1GHz) bands are achieved using two parasitic stubs that are attached to the patch, and an inverted U-shaped slot that is etched on the transmission line, respectively. The proposed structure is printed on FR4 material and operates over the frequency range between 2.57-11.3 GHz with WiMAX and ITU dual notched bands characteristics. The measured results of the proposed antenna with overall size of 23×32 mm 2 show acceptable performance and good agreement with the simulated results
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
Design and analysis of a compact dual‐band bandpass filter using V‐ and W‐shaped microstrip open lines
(Wiley, 2019) Lahmissi, Ahmed; Challal, Mouloud
Design and evaluation of an antenna applicator for a microwave colonoscopy system
(IEEE, 2019) Guardiola, Marta; Djafri, Kahina; Challal, Mouloud; Gonzalez Ballester, Miguel A.; Fernandez-Esparrach, Gloria; Camara, Oscar; Romeu, Jordi