| Manuscript Title: | W-Band Linear Array of Planar Antennas and Chiral Metamaterial Cover |
| Manuscript Id: | IJMOT-2014-8-621 |
| Abstract: | This work presents the development of a W-band planar antenna array, starting from the study of a single element, evaluating the effect of a chiral cover on it, then incrementing to the design, fabrication and measurements of a W-band linear array of three planar antennas. Each radiating element is a patch fed by slots. This technology is cheap and affordable. Simulation fits quite well with measurements. Metamaterial may enhance the radiation properties, particularly, the directivity. The chiral metamaterial cover is made of two layers of mutually twisted planar metal rosettes in parallel planes. |
| Authors: | Jéssica Gutiérrez, Óscar Fernández, Juan Pablo Pascual, Álvaro Gómez, Antonio Tazón, Ángel Vegas, Ángel Mediavilla |
| Submitted On: | 10/09/2014 |
| Pages: | 384-393 |
| Action: | [Full Paper]
No. of Downloads: 107 |
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| Manuscript Title: | A Novel Design of A Microstrip 3dB Coupler |
| Manuscript Id: | IJMOT-2014-8-622 |
| Abstract: | This paper presents a novel design of branch 3dB coupler, it is designed and simulated by using FR4 substrate at the operating frequency 2.45 GHz in the ISM "Industrial Scientific Medical" band. The design is based on two different models, the T-model and combinational-model (T- and p-model) in order to reduce the size and improve the performances. After a theoretical study on the use of open stubs, we present the simulation results of this branch line coupler by using ADS from Agilent technologies and CST Microwave Studio. Good agreement is found between simulated and measured results. |
| Authors: | A. Sardi, J. Zbitou, A. Errkik, L. El Abdellaoui, A. Tajmouati, M. Latrach |
| Submitted On: | 10/09/2014 |
| Pages: | 394-399 |
| Action: | [Full Paper]
No. of Downloads: 65 |
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| Manuscript Title: | New Compact Antennas Structures with a slot shaped and a Stub Tuning for Ultra Wide Band Applications |
| Manuscript Id: | IJMOT-2014-8-623 |
| Abstract: | This paper presents the design of new compact printed broadband antennas for Ultra Wide Band applications. The antenna structures are based on the CPW-fed combined with a slot and a stub line to increase the bandwidth. The proposed antennas have been successfully designed, optimized and simulated by using Momentum software integrated into ADS "Advanced Design System" and CST Microwave Studio. The measured input impedance bandwidth of the final broadband antennas ranging from 2.1-7.3 GHz and 2.1-11 GHz. The design considerations for achieving broadband antennas and both simulated, experimental results are presented and discussed. |
| Authors: | R. Dakir, J. Zbitou, A. Mouhsen, A. Tribak, A. M. Sanchez, M. Latrach |
| Submitted On: | 10/09/2014 |
| Pages: | 400-408 |
| Action: | [Full Paper]
No. of Downloads: 63 |
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| Manuscript Title: | Novel Ridged Waveguide Differential Phase Shifter for Satellite Application |
| Manuscript Id: | IJMOT-2014-8-624 |
| Abstract: | A compact differential phase shifter structure that exhibits both full-band operation and easy mechanical manufacture is presented. It consists of a rectangular waveguide loaded with single ridge sections terminated by a unique H-plane step widening to standard waveguide dimensions. Two prototypes of 90º and 180º differential phase shifters with reference to an empty waveguide of the same length were designed and tested for the WR75 waveguide band. In both cases the differential phase shifter exhibits a maximum measured phase error of ±2.5º and ±3.5º respectively, with return losses better than 24 dB and insertion losses lower than 0.06 dB over a >40% bandwidth, which represents state-of-the-art achievement for non-dielectric loaded waveguide circuits. Furthermore, this structure is well suited for H-plane millimetre-wave integration. |
| Authors: | Abdelwahed Tribak, Angel Mediavilla, Jamal Zbitou, Juan Luis Cano |
| Submitted On: | 10/09/2014 |
| Pages: | 409-414 |
| Action: | [Full Paper]
No. of Downloads: 30 |
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| Manuscript Title: | Novel Design of Miniaturized Broad Stopband Bandpass Filter using Defected Ground Structure |
| Manuscript Id: | IJMOT-2014-8-625 |
| Abstract: | In this paper, a new compact microstrip bandpass filter (BPF) employing two identical modified dumbbell-shaped defected ground structure (DGS) patterns and a pair of 50 O end-coupled microstrip lines is suggested. The proposed BPF has small size, a bandwidth of 0.52 GHz and an insertion loss of 3 dB. Furthermore, it has around – 28 dB suppression level up to 6 GHz. Experimental data and simulation results are in good agreement. |
| Authors: | Mouloud Challal, Mokrane Dehmas, Arab Azrar, Rabia Aksas, Mohamed Trabelsi |
| Submitted On: | 10/09/2014 |
| Pages: | 415-420 |
| Action: | [Full Paper]
No. of Downloads: 38 |
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| Manuscript Title: | Hybridization Approches of Metaheuristics for\r\nOptimal Analog Circuit Design |
| Manuscript Id: | IJMOT-2014-8-627 |
| Abstract: | The analog circuit design is a hard complex and time consuming task. Recently, Ant Colony Optimization algorithm (ACO) has emerged as a powerful and useful method for optimal design of analog circuits, based on the finding of the good compromise between the most important performances or merits figure of a given circuit. As a drawback it needs longer time execution when compared for instance to the genetic algorithm (GA) or to the simulated annealing (SA) one. In order to improve execution speed, we propose to combine the ACO to both the GA and SA algorithms to build up two new hybrid algorithms (SA-ACO) and (GA-ACO). The main idea is first, to use the GA or SA algorithm to explore the promising search space and secondly, to exploit the best solutions by the ACO algorithms to rapidly achieve the optimal solution. The obtained hybrid algorithms (SA-ACO) and (GA-ACO) are finally used for the sizing of a CMOS second generation current conveyor (CCII) and an operational amplifier (Op-Amp). The performances of the proposed algorithms will be highlighted in terms of computing time, convergence rate and the optimum quality. |
| Authors: | Bachir Benhala |
| Submitted On: | 10/09/2014 |
| Pages: | 421-428 |
| Action: | [Full Paper]
No. of Downloads: 21 |
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| Manuscript Title: | Realization of a dedicated bench for reliability and robustness studies of high Si-LDMOS power transistors |
| Manuscript Id: | IJMOT-2014-8-628 |
| Abstract: | We present in this paper the conception and realization of a dedicated ageing workbench to study and evaluate power microwave transistors performances. This bench has the particularity to address high power RF (radio frequency) transistors reaching one kWatt over the L-band, in operational conditions for radar applications. In-situ electrical measurements can be achieved, thus avoiding a calibration of the bench. Considering three kinds of stresses, we present results regarding the performance and reversible damage of a high power commercial Si-LDMOS transistor. |
| Authors: | Pascal Dherbécourt, Olivier Latry, Eric Joubert, Karine Dehais-Mourgues, Hichame Maanane2, \r\nJean-Pierre Sipma, Philippe Eudeline |
| Submitted On: | 10/09/2014 |
| Pages: | 429-436 |
| Action: | [Full Paper]
No. of Downloads: 21 |
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| Manuscript Title: | Channel Capacity Maximization in Multiuser Large Scale MIMO-Based Cognitive Networks |
| Manuscript Id: | IJMOT-2014-8-630 |
| Abstract: | This paper proposes an adaptive multi-user Multiple Input Multiple Output (MIMO)-Space Division Multiplexing Access (SDMA) technique for uplink access in broadband wireless cognitive networks with multiple primary users (PUs) and secondary users (SUs) sharing the same spectrum. The proposed algorithm uses gradient search of the channel capacity to seek, iteratively, the optimal transmit weight vectors that maximize the MIMO channel capacity for each cognitive user, while controlling the interference levels to the PUs. Simulation results show that the symbol error rate (SER) performance and the capacity of cognitive MIMO systems using the proposed adaptive MIMO-SDMA algorithm is substantially higher than the one based on conventional approaches such as eigen-beamforming. The paper also investigates the performance of large scale MIMO-SDMA system and shows that as the number of base station antennas becomes larger, the constraints imposed by the primary network could be relaxed and the performance of SUs is improved without harming the Pus performance. |
| Authors: | Mostafa Hefnawi, Ahmed Abubaker |
| Submitted On: | 10/09/2014 |
| Pages: | 437-444 |
| Action: | [Full Paper]
No. of Downloads: 25 |
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| Manuscript Title: | Spectral Management for a Cognitive Radio Application with Adaptive Modulation and Coding |
| Manuscript Id: | IJMOT-2014-8-631 |
| Abstract: | Cognitive Radio allows Software Defined Radio terminal to perceive its environment and then interact with it. In other words, cognitive radio can collect information from its surroundings, model them and try to adapt its behavior according to them. The main aim of this paper is to shed light on the concept of spectrum sensing and adaptive cognitive radio and propose an application implemented on Small Form Factor (SFF) Software Defined Radio (SDR) development platform. This application includes both a spectrum sensing algorithm based on Fast Fourier Transform which is basically insensitive to noise level and an Adaptive Modulation and Coding (AMC) scheme. The validation of the proposed cognitive radio application and the efficiency of the AMC and the spectrum sensing algorithms are shown through experiments and measurement results. |
| Authors: | Mohammed Amine Azza, Ali El Moussati, Slimane Mekaoui, Kamal Ghoumid |
| Submitted On: | 10/09/2014 |
| Pages: | 445-452 |
| Action: | [Full Paper]
No. of Downloads: 20 |
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| Manuscript Title: | Effective Fermi Level Modulation of Coupled Graphene-Metal Surface Plasmon Polaritons at Sub-THz Frequency Range |
| Manuscript Id: | IJMOT-2014-8-626 |
| Abstract: | In this paper we investigate how one can take additional advantage of coupled metal graphene plasmons. The dispersion relation for coupled metal graphene plasmons is presented here for a proposed multilayer structure. Graphene and couple metal graphene modes supported by this structure are shown below, these modes can depend very strongly on Fermi energy level values in the graphene layer at the sub-THz frequency range, which eventually can be used in a wide range of applications. |
| Authors: | Hameda Alkorre, Gennady Shkerdin, Johan Stiens, Youssef Trabelsi, Roger Vounckx |
| Submitted On: | 10/09/2014 |
| Pages: | 453-459 |
| Action: | [Full Paper]
No. of Downloads: 20 |
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| Manuscript Title: | Performance Evaluation of Radio over Fiber System Model in Multipath Fading Channel at 60 GHz |
| Manuscript Id: | IJMOT-2014-8-629 |
| Abstract: | Providing high data rates and wide bandwidth applications are the most important challenges that mobile systems and radio networks are trying to accomplish. Radio over Fiber (RoF) system is a promoting research field since it benefits of Passive Optical Network (PON) advantages and unlicensed large bands in 60 GHz millimeter band (57-64GHz). In this study, we consider a complete downlink RoF system from the central office to the end-user passing by the base station and we study the impact of the propagation environment on the whole system performance and the radio coverage. Different scenarios for multipath propagation are considered (Line of Sight-LOS, Non Line of Sight-NLOF). In particular, we have been interested in Rayleigh and Rice propagation models for both indoor and outdoor environments. Optisystem/ADSCo-simulationhas been investigated to simulate RoF network coverage for indoor and outdoor environments while considering IEEE 802.15.3C application classes and assuming 16-QAM, Q-PSK and B-PSK modulation formats. |
| Authors: | Sarra Rebhi, Rim Barrak, Mourad Menif, Ali El Moussati |
| Submitted On: | 10/09/2014 |
| Pages: | 460-467 |
| Action: | [Full Paper]
No. of Downloads: 29 |
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