Patch antenna is a low-profile antenna that has a number of advantages, low cost, light weight,easy to feed and their attractive radiation characteristics. For aWiMAX communication system, a ...microstrip patch antenna which operates at 2.76 GHz frequency band was presented in this work. The hybrid system solar cell antenna allows energy recovery as well as RF Transmission. A simulation process, withMATLAB, is used to determine the electrical power collected by the studied system as a photovoltaic cell. As a antenna, parameters such as gain, directivity, radiation pattern and radiated power were studied. Simulation results, showed a resonance frequency of the antenna at 2.76 GHz with an effective return loss of -18.64dB and a gain of 6.58dBi. Thereafter, an optical rectenna based on a solar cell antenna was proposed and studied.
This paper describes a new multi-resolution approach for the blind separation of convolutive image mixtures in transform domain. The proposed method uses an Adaptive Vectorial case of Quincunx ...Lifting Scheme (AVQLS), based on wavelet decomposition, and a geometric unmixing algorithm. It proceeds in three steps: first, the mixed images are decomposed by AVQLS. Then, the unmixing algorithm is applied to the more relevant component to get a transformed estimate of the original images. An inverse transform is, thereafter, applied to obtain an estimate of the original images. Experiments carried out on medical images showed that the proposed method yields better separation results than many widely used blind source separation algorithms.
E-commerce security is very important especially nowadays but internet is entrusted due to the attacks and hackers exploitations. To improve the security of electronics transactions, many protocols ...are developed. SSL/TLS is the most commonly used, although many dangerous attacks were found. So, developers have to upgrade SSL/TLS to avoid these attacks and enhance security. To achieve their goals, hackers exploit flaws and errors found in SSL/TLS protocol implementations, it is necessary to verify and validate the security of the entire software code. Therefore, to improve the security of SSL/TLS protocol, researchers try to find solutions; protocols must therefore be tested and validated before their launch. In this paper, we will focus on analyzing SSL/TLS protocol with automated formal verification tool AVISPA. We study the renegotiation attack and try to detect it using AVISPA. We use formal models for automatic verification of security protocol to discover new attacks, to prevent similar attack in the future and also to increase the tool efficiency.
Three efficient infrared‐printed dipole nano‐antennas are designed on a dielectric substrate for infrared energy harvesting. The three printed dipoles have different shapes, namely, rectangular, ...curved bowtie, and elliptical. These antennas are designed in to collect maximum electric field in the gap between the two poles in the frequency band of 28to 29THz, which is chosen because the received infrared power is maximum at 28.3 THz. A parametric study of the three proposed dipole shapes is performed to increase the localized electric field as well as modify to achieve resonance frequency at 28.3 THz. A parametric study is carried out to determine the dipole length, width, gap size, substrate thickness, and ground plane thickness. Next, the three dipoles are exposed to different polarizations incident plane waves in order to study the effect of the polarization of the incident wave on the electric field induced in the gap and to compare the performances of the three designs. The comparison study shows that at 28.3 THz, the curved bowtie dipole shape collects a larger electric field than the rectangular and elliptical shapesdo.
This paper presents a contribution to the study of the effectiveness of the electromagnetic shielding (a metal enclosure integrating a ventilation aperture for the internal circuit). The employed ...analysis method is based on the concept of wave (Fast Wave Concept Iterative Process-FWCIP). This method is easy to implement and always convergent, using the Fourier modal transform "FMT" which considerably reduces the calculation time. It was applied to characterize the effect of the upper cover box's height on the shielding effectiveness. The results were compared with those obtained by the HFSS software from Ansoft. They are in good agreement and show the effectiveness of the proposed method for the study of such problems.
In this article an efficient algorithm based on the wave concept iterative process is formulated and applied in order to investigate the electromagnetic scattering by a set of conducting arbitrarily ...shaped objects placed in the free space. In this approach, the cylindrical coordinates system is used as a modal base in order to develop the modal coefficients of the diffraction operator. This operator models the reaction of the environment expressing the electromagnetic coupling between each two pixels of the discretized surface. A study of electromagnetic coupling between two pixels positioned and oriented somehow in the free space is highlighted so as to determine the coupling operator for different positions and orientations of the emitted and received waves. Twelve coupling operators are developed. For a complex geometric shape structure, the determination of these characteristics involved the determination of interactions between each pixel and the others that constitute the discretized surface. This interaction involves the wave formulation already highlighted for each couple of pixels which implies a higher calculation time. In order to optimize the calculation time, the artificial neural networks are adopted with the feed‐forward architecture. The supervised learning has been chosen with the use of the resilient backpropagation algorithm.
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