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by Ehab K. I. Hamad, Adel A. A. Abdel-Raheem

Vol. 3. n. 1, pp. 1-8

Abstract - In this paper, the performance of a square microstrip patch antenna is improved using planer Left-Handed Metamaterial (LHM) layer composed of 2-D periodic structure of rectangular Split Ring Resonator (SRR) and Thin Wire (TW). The microstrip antenna is fed by a coaxial probe and then incorporated with the LHM layer, which is suspended above the patch through a nylon spacer. Based on the negative refractive index (NRI) of the LHM perfect lens, the radiated electromagnetic beam is focused and the beam area is reduced. As a result, the gain and the directivity of the patch antenna as well as the radiation efficiency increase. The optimized radiation properties of the proposed antenna are achieved using a finite-element-method-based 3D full-wave electromagnetic simulator. A parametric analysis is carried out to design and optimize the SRRs/TWs-based LHM layer with NRI in a specific frequency range to be matched with the original patch antenna bandwidth. The results demonstrate that an enhancement in the gain and directivity by 3.5 dB, in the radiation efficiency by 11% of its original value withoutt MTM layer, and a reduction in the beam area by 15 %.

Keywords: Microstrip Patch Antenna, Left-Handed Metamaterials, Double Negative Materials, Negative Refractive Index, Split Ring Resonators, Thin Wires.

by Majed Omar Al-Dwairi, Dmitriy E. Skopin

Vol. 3. n. 1, pp. 9-15

Abstract - This paper investigates multilevel amplitude shift keying (M-ASK), M-ASK combined with differential phase shift keying (M-ASK-Bipolar), Quaternary Amplitude Shift Keying (QASK) and Quaternary Polarization-ASK (QPol-ASK) at a total bit rate of 107 Gbps. The aim is to find a cost-effective very high speed transport solution. Numerical investigation was performed using Monte Carlo simulations. The obtained results indicate that the proposed modulation formats can be operated at 100Gbps in optical communication systems with low implementation effort and high spectral efficiency.

Keywords: Optical Communication, Multilevel Amplitude Shift Keying (M-ASK), Differential Phase Shift Keying (DPSK), Quaternary Amplitude Shift Keying (QASK), Quaternary Polarization-ASK (Qpol-ASK).

by A-K. Hamid

Vol. 3. n. 1, pp. 16-20

Abstract - An exact solution is presented to the problem of scattering of a plane wave by a chiral semi-elliptic-cylindrical boss located on an infinite perfectly conducting ground plane. The problem is formulated by expressing the incident, reflected, scattered as well as the transmitted electromagnetic fields in terms of appropriate angular and radial Mathieu functions and sets of expansion coefficients. The unknown expansion coefficients can be determined by imposing the appropriate boundary conditions on the surface of the chiral semi elliptical cylinder. Numerical results are presented for normalized backscattering widths of semi-elliptic-cylindrical bosses of different chiral material, to show the effects of these on it.

Keywords: Chiral Material, Elliptical Boss, Co and Cross Polarizations, Mathieu Functions, Scattering.

by Houriyeh Shadmehr, Francesco Grimaccia, Giambattista Gruosso, Marco Mussetta, Riccardo E. Zich

Vol. 3. n. 1, pp. 21-26

Abstract - In this paper, an equivalent model based on two identical loop wire antennas separated by an air gap are studies in order to design an optimized antenna for Wireless Power Transfer (WPT) to improve the wireless link performance of WPT. The optimization method was utilized in this work, named Genetic Swarm Optimization (GSO). GSO has been already successfully applied to the optimization of antennas, wireless systems and energy harvesting devices, usually allowing to reduce the number of iterations, and thus the computational effort, required to optimize complex electromagnetic problems. Simulation is done byMoMMatlab code; and then the power efficiency is calculated for optimal antennas in order to show the impact of the designing optimal antennas. Furthermore, the results are verified by comparison with FEKO Lite.

Keywords: Wireless Power Transfer, Optimization.

by Priya Rahul

Vol. 3. n. 1, pp. 27-32

Abstract - In the proposed paper, a planar monopole antenna with modified patch and truncated ground plane for Ultra wideband (UWB) applications is presented. The radiating element of the proposed antenna is fed by a 50 Ω microstrip line. Truncation in the ground plane is made for better impedance matching. It is found that by making steps in the ground plane, return loss characteristics and hence the VSWR is improved. The antenna parameters and performances have been investigated by using commercially available CST Microwave Studio software. Simulation and measurement results show that the proposed antenna provides an ultra wide bandwidth, completely covering the range set by the Federal Communication Commision (FCC) for UWB operations (3.1 GHz to 10.6 GHz).The antenna is of low profile and exhibits omnidirectional radiation pattern and high gain for the entire bandwidth.

Keywords: UWB, Planar Monopole Antenna, Microstrip Fed, Truncated Ground Plane.

by S. Mazer, C. Algani, M. El Bekkali

Vol. 3. n. 1, pp. 33-36

Abstract - In Ultra WideBand (UWB) High Data Rates(HDR) communications, two modulations schemes are in competition. The first one is an impulse-based BPSK modulation (IR, Impulse Radio). The second one is a Multi-Band Orthogonal Frequency-Division Multiplexing (MB-OFDM). A third modulation scheme has been proposed by Mitsubishi. It is an Impulse Radio Multi-Band On-Off Keying modulation (MB-OOK), which combines the advantages of the first two modulation schemes. This paper deals with the modeling of a complete UWB MB-OOK link under the Agilent-ADS (Advanced Design System). The focus will be on the receiver’s performance based on non coherent energy detection.

Keywords: UWB, Impulse Radio, Generator Circuit,OFDM, MB-OOK, Correlator, Filters.

by M. A. Mebrek, L. H. Abderrahmane

Vol. 3. n. 1, pp. 37-41

Abstract - In this paper, we will do a study which consists in simulation and configuration of a parabolic antenna embedded in the payload of a geostationary satellite in Ka-band; this antenna is responsible to ensure the communication between the satellite and receptor or earth station for multimedia service. First, we will study the parabolic antenna because it’s this type of antenna who interest us in our application, and we will study their different characteristics, after we will study the different types of parabolic antenna to choose the most appropriate model, in our study the parabolic antenna mounted in offset is the most appropriate. Finally, we will use specific software to simulate the antenna for arriving to determinate the different parameters that can give us the best performances practically.

Keywords: Telecommunication Satellite, Offset Parabolic Antenna, Payload, Gain, Beam Width, Aperture Efficiency, Ka Band.

by Shuvashis Dey, Nandita Saha

Vol. 3. n. 1, pp. 42-50

Abstract - In this paper the design of textile antennas for materials with three different substrate permittivity εr =3, 2.12, 2.22 are realized. Different textile substrates having different permittivity affect the antenna performance in various ways. Here, Microstrip Patch Antenna is designed for narrow band WBAN (Wearable Body Area Network) at the frequency level of 2.45GHz & also a design of circular disc monopole textile antenna with the operating frequency of 2.5GHz to 5GHz for UWB (Ultra Wide Band) is realized. For all design, Dacron fabric, denim jeans fabric and thick fleece fabric are used as antenna substrates & woven copper threads are used as the conductive part of the antenna patch. This paper demonstrates the effects of antenna bending at three different angles for both the antennas with denim jeans substrate. Here, resonance frequency fluctuations due to impedance matching as well as effects of radiation pattern deformation due to bending for different textile material substrates are focused. Several antennas have been tested on different substrates with acceptable performance. But this paper concentrates on textiles substrates rather than others. However here, with what extent the antenna will manage to give better performance with flexibility of textile material are mainly observed.

Keywords: Microstrip Patch Antenna, Narrow Band, Antenna Bending, Permittivity, WBAN, Circular Disc Monopole Antenna, Ultra Wide Band.

by Anselm Mathias, Sajid M. Sheikh, Morgan Richomme, Annah M. Jeffrey

Vol. 3. n. 1, pp. 51-55

Abstract - Radio is defined as communication of audible signals encoded in electromagnetic waves. Web Radio makes use of the internet to both transmit audio signals and to listen to the radio. This paper presents the results from a market research that was carried out to explore the radio industry in Botswana and the technology used. The objective of the study was to find out the implication of radio on the society, the impact of the web on traditional FM radio that is, how it has been affected, the types of applications that are currently being use, and the interaction with the open source community. A census survey methodology approach was adapted and information was acquired through site visits and interview sessions. Study results show that current media is heavily dependent on the web (social media's like Facebook and Twitter) and that traditional FM Broadcasters in Botswana are also moving towards online broadcasting with sophisticated technology. Furthermore, most applications that are used are not open source.

Keywords: Radio, Web-radio, Open Source, Internet.

by Abu Bakar Md. Sultan, Abubakar Diwani Bakar, Hazura Zulzalil, Jamilah Din

Vol. 3. n. 1, pp. 56-60

Abstract - Background: Trustworthiness takes an important attention in software development paradigm. It is one of the important aspects in software adaptation. This confidence characteristic works more closely in OSS development paradigm where development practice is more abstract. Aims: This paper is set out to examine the factors in the evaluation of trustworthiness of open source software Method: This systematic literature review surveyed the articles published between 2007 and 2012 in five most repository of research paradigm. The results: The study identified the reliability and interoperability as the top most important factors for the OSS practitioners to take into consideration in their software adaptation. Conclusion: The study discusses the systematic literature review on how to identify the trustworthiness of the open source software and find out that reliability is the highest ranking factors that is needed to be considered in the adoption of the software. Further theoretical and empirical research is still needed on this area. Researchers can work more in this area by validating these findings empirically to gain more facts about this area.

Keywords: Trustworthiness, Open Source Software, Reliability, Interoperability, Trustworthiness.

by M. Houssini, M. El-Khatib, A. Hamié, P. Blondy, K. Abou-Saleh, A. Ghaddar, H. Alaeddine

Vol. 3. n. 1, pp. 61-67

Abstract - This paper represents a new and original design of a Metamaterial circuit based on matrix of resonator cells using variable analog MEMS capacitors ‘varactors’, periodically distributed in some way to fulfill a multiple applications circuit, whose one is a tunable pass band-filter. The cells are connected together with lumped elements computed using hybrid circuit EM simulation and allow precise computation of the frequency shift for every changing of the capacitive load. The design is extremely dynamic and can be used for numerous applications due to the agility in controlling the varactors. Those later, are actuated in some manner to achieve a tunable 2-pole pass-band filter, its center frequency is analogically and then digitally tuned from 11 to 12.6 GHz. Return losses less than 15 dB and insertion losses better than 1 dB over the whole operation band. The circuit has been conceived on a 525 µm-thick quartz substrate and it occupies a total area of 1.48x0.79 cm². Finally, we discuss the challenging and opportunities in the field of Metamaterials based on RF MEMS.

Keywords: RF MEMS, Metamaterial, Hybrid Simulation, Pass-Band Filter.

by Hamze Haidar Alaeddine, El Houssain Baghious, Gilles Burel

Vol. 3. n. 1, pp. 68-76

Abstract - This paper is about an efficient implementation of adaptive filtering for echo cancelers. Recently a fast converging algorithm called Robust Proportionate Normalized Least Mean Squares (RPNLMS++) against double-talk has been proposed. This paper presents a realization of an improved version of the previous RPNLMS++ adaptive filter using block structure in which the filter coefficients are adjusted one per each output block. Then, an efficient implementation of the block filtering process is proposed using Number Theoretic Transforms (NTT) which can significantly reduce the computation complexity of filter implantation on Digital Signal Processor (DSP). Analyses of convergence properties, during single and double-talk, and complexity show that the new block adaptive filter permits fast implementations while maintaining performance equivalent to that of the widely used RPNLMS++ adaptive filter.

Keywords: Adaptive Filters, Echo Canceller, Robust Proportionate Normalized Least Mean Squares (RPNLMS++), Fermat Number Transform.

by R. Sharma, M. Kumar

Vol. 3. n. 1, pp. 77-82

Abstract - A dual band printed microstrip patch antenna consisting of double square patch with 2-bridges is designed and proposed in this paper. The antenna operates at two resonating frequencies of 2.4GHz and 9.7GHz. FR-4 substrate is used for designing the antenna which has a dielectric constant of 4.4 and thickness of 1.6 millimeter (mm). The antenna has a compact size of 40×40 mm² including the ground plane whose size is same as that of substrate. It is fed with 50Ω coaxial feed line. The proposed antenna has bidirectional radiation characteristics with good simulated return loss lower than -10dB. The electromagnetic (EM) simulation software is used for the simulation. The antenna has ease of designing, low manufacturing cost and small size which can be easily integrable in portable communication devices. Two square patches are aimed to obtain dual band operation. The larger patch resonates at 2.4GHz and the smaller patch resonates at 9.7GHz respectively. This antenna can be used for wireless local area networks (WLAN) and radio navigation or radio location applications in S-band and X-band respectively at low powers. Simulation results are in good agreement with the measurement results.

Keywords: Dual Band Antenna, Microstrip Antennas, Patch Antenna.