Jamel Belhadj Tahar

Meta-materials applications in thin- film sensing and sensing liquids properties.

This paper is devoted to study one of the most important applications of metamaterials based on Split Ring Resonator (SRR) which is thin-film sensing and sensing liquids properties. We provide a broad overview of thin film deposition methods, depositing the substance material in the gap, under the rings or on the rings. The sensor allows to extract various information about the dielectric properties and the loss from the resonant frequency. The analyses process consists of comparing the resonant shift to characterize the liquid type and the resonant dip to examine the impurities induced in the liquid. Split rings accommodate a wide range of individual preferences and sensing abilities. We demonstrate sensing features of rectangular split rings designed to resonate in the frequency range of 8-12 GHz.

Heuristic inspired search method for fast wedgelet pattern decision in 3D-HEVC

The 3D High Efficiency Video Coding (3D-HEVC) is the latest 3D extension of the HEVC video coding standard. It supports multi-view videos plus depth (MVD), which is a sophisticated format for enhanced 3D content. Depth modeling modes (DMM) are adopted in the 3D-HEVC for better sharp edge encoding. However, employing DMM causes important computational complexity. In this paper, we propose a new method for fast wedgelet pattern decision in 3D-HEVC. In order to avoid unnecessary evaluation of the DMMs, a new early termination based on the smoothness of the current block is adopted. Besides, based on the shuffled frog leaping algorithm, a new heuristic method to search the optimal wedgelet pattern for DMM1 Depth mode is introduced. The proposed algorithm outperforms the HTM16.0 implemented scheme in terms of encoding time with similar coding efficiency.

Clustering-based fast intra prediction mode algorithm for HEVC

The High Efficiency Video Coding (HEVC) is the next generation video coding standard. The HEVC provides equivalent perceptual quality with bit-budget saving greater than 50% compared to the H.264/AVC. In this paper, we propose a new fast intra prediction mode decision algorithm for the HEVC. We apply an early termination method based on the statistics of the resulted IPMs from both rough mode decision and most probable mode stages. The resulted IPMs are clustered into a K cluster by means of the K-medoid clustering algorithm, and each IPM cluster center represents all the IPMs within a cluster for the RDO process. The sugeested algorithm has been evaluated on high resolution test video sequences. Compared with the current HM16.0 and state-of-the-art scheme in all intra high efficiency configuration cases, the proposed algorithm outperforms the state-of-the-art scheme in terms of encoding time with similar coding efficiency.

Investigation of capacity loss and mean effective gain in multiple antenna systems

This paper presents the evaluation of Multiple Input Multiple Output (MIMO) systems by analyzing essentially the Capacity Loss, Mean Effective Gain, Effective Diversity Gain and Multiplexing Efficiency. The proposed antenna consists of a pair of folded L-shaped strips patch antenna which are placed side by side and printed on a dielectric substrate for Wireless Local Area Network (WLAN) application at 5.2 GHz. The distance between the two radiating elements is very small and equal to 3.6mm. By including Squared Split Ring Resonators (SSRRs) in the partially removed part of the substrate, the characteristics of the new design have been ameliorated.

Low complexity intra prediction mode decision for 3D-HEVC depth coding

Abstract The 3D High Efficiency Video Coding (3D-HEVC) is the latest 3D extension of the HEVC video coding standard. It supports multi-view videos plus depth (MVD), which is a sophisticated format for enhanced 3D content. Depth modeling modes (DMM) are adopted in the 3D-HEVC for better sharp edge encoding. However, employing DMM causes important increase of computational complexity. In this paper, we propose a three steps scheme for fast intra depth coding in 3D-HEVC. Based on the kirsch edge detection algorithm, a fast angular mode decision algorithm is performed. In order to avoid unnecessary evaluation of the DMMs, a new early termination approach (ET) based on the smoothness of the processed block is adopted. Besides, based on the enhanced shuffled frog leaping algorithm (E-SFLA), a new heuristic method to search the optimal wedgelet pattern for DMM1 Depth mode is introduced. The proposed algorithm is implemented on the top of four different versions of HTM. It outperforms HTM-16.0, the latest used version, and four different work from the literature, in terms of encoding time with similar coding and quality efficiency.

Optimization of 60 GHz MIMO antenna by adding ground stub to reduce mutual coupling for WPAN applications

In this paper a novel 60 GHz printed antenna with defected ground structure is proposed for MIMO application. The antenna consists of a pairs of folded L-shaped strips patch printed on silicon subtract for wireless personal area network (WPAN) at 60 GHz. The two radiating elements are separated by distance equal to 1.25 mm. The performance of the proposed antenna has been evaluated after adding the cone ground stub especially the mutual coupling. Proposed antenna is resonating at 60 GHz. Return loss of −17.85 dB is achieved for 60 GHz band. The mutual coupling is less than −15 dB throughout the bandwidth (56 GHz–64 GHz). The simulation results indicate that the antenna can provide spatial diversity and enhance isolation.

Perceptually-adaptive quantization for stereoscopic video coding

In this paper, we present a novel perceptually-based optimization for the improvement of stereoscopic video coding efficiency. The main idea of this proposed scheme is to adaptively adjust the quantization parameter by taking into account the Human Visual System perceptual characteristics. For this, a saliency map is generated from both views and then segmented into salient and non-salient regions. To make the proposed scheme effective, and inspired from the binocular suppression theory, the asymmetry is ensured by altering the saliency map and not the view. As a result, the proposed perceptual coding scheme effectively reduces the bit-budget without affecting the perceptual quality based on an optimization approach with asymmetric video coding taking into account the saliency map of each view. Experimental results on HEVC-MV show that the proposed algorithm can achieve over 20% bit-rate saving while preserving the perceived image quality.

Four-element MIMO antenna with refined isolation thanks to spiral resonators

To relieve the performance degradation of a 4×4 Multiple-Input Multiple-Output system caused by the strong mutual coupling among the four patch elements, a metamaterial spiral resonator (SR) is proposed as an effective solution. Applying the proposed periodic structure in the substrate and between the patches is simulated and studied. This design could be used to develop a more compact multi-antenna Wi-Fi (IEEE 802.11n) system at 5.5 GHz.

Improved antenna diversity system by low correlation between elements exploiting Single-Negative Metamaterials

In this paper, we propose a two-element diversityantenna array at the worldwide interoperability for microwave access WiMAX band 3.5 GHz (3.4-3.6GHz) for the MultipleInput Multiple-Output (MIMO) applications. Each element is a coplanar waveguide (CPW) fed wide rectangular slot antenna with a widened tuning stub. An insulator which consists of Single-Negative Metamaterials (SNG) is added between the two elements (back to back) in order to enhance the isolation characteristic for the designed MIMO antennas. Antenna characteristics such as, scattering parameters, envelope correlation and diversity gain with and without the presence of SNG are provided. The proposed technique achieved a 17.09 dB reduction in mutual coupling at 3.5 GHz.

New design of antenna array using left handed meta-material “LHM” based on circular Split Ring Resonator “SRR”

In the first part of this paper, we explain the basic concept of left-handed material and we will look at the history of implementing LHM materials at high frequency. In this part we have investigated the characterization process of metamaterials, the effective dielectric and magnetic properties are retrieved from the scattering parameters. Moreover, we provide a detailed study about the effective parameters such as the refractive index, permeability, permittivity and the group delay. For this purpose we have designed special LHMs that resonate in X-band frequency which is around 8GHz–12GHz. In the second part of this paper, a new topology for designing a circularly polarized 2 × 4 linear antenna array composed of circular Split Ring Resonator SRR for X-band is discussed. The design of metamaterial antenna array based Circular Split Ring Resonator operating at about 10.75 GHz and present a gain of 5.2 dB and the aperture at −3dB is 58°.