Analyze of Frequency Selective Surfaces By Hybrid MOM-PO-GTD Method

The intent of this article is to analyze the Diraction phenomena of the incoming waveand provide a new Approach for analyzing the frequency selective surface (Fss) by usinga hybrid method combining Moment Method (MoM), optical physics (PO) with Generaltheory of Diraction (GTD). the frequency selective surface (Fss) is a periodic surfacewith identical two-dimensional arrays of elements arranged on a substrate dielectric. Anincoming plane wave will either be transmitted (bandwidth) or re ected (stopband),completely or partially, depending on the nature of the array element. This happenswhen the frequency of the electromagnetic (EM) wave correspond with the resonantfrequency of the FSS elements. Hence, in free space, and for a certain frequency range,an FSS is capable of transmitting or blocking EM waves; therefore, identied as spa-tial lters. Today, FSSs have been extensively studied and there is tremendous growthin its design and implementation for dierent applications at the microwave to opticalfrequency ranges. In this review article, we present a new hybrid method form on Mo-ment method and GTD for analyzing dierent categories of FSS based on the design ofthe structure, the array elements used, and applications. We also focus on the eectsof diraction, methodology, experimental verications of design examples, as well ason prospects and challenges, particularly in the microwave regime. We highlight theirimportant performance metrics, especially with regard to progress in this area couldfacilitate advanced electromagnetic innovation

Analysis the effect of Diffraction Phenomena by Complex Shapes with Hybrid MOM-GTD Method

This article deals with a hybrid method combining the method of moments (MOM) with the general theory of diffraction (GTD). This hybrid approach is used to analyze antennas located near perfectly Bodies of arbitrary curved shape. Some examples, e.g. an antenna mounted near a perfect conductor cylinder with two plates, demonstrates that the hybrid approach is the most suitable technique for modeling large-scale objects and arbitrary shapes. This approach allows us to resolve the problem, that the other methods can’t solve it alone. Generally, random radiation locates on or near an arbitrary form, can be solved using this technique hence the strong advantages of our method

Enhanced thresholding-based wavelet noise filtering in optical fiber communications

Nowadays, the growing requirement of higher data transmission rates for real-time applications of communication systems. The capacity of data transmission increased with the higher carrier frequency. Optical Fiber Communication (OFC) systems gained a significant interest of researchers due to its capability of enhancing the data-carrying capacity. The optical waves in OFC systems operate in the range of THz those results in the increased capacity of data-carrying. The OFC systems achieved a high data rate, however, suffered from the challenges of various noises. The presence of noises in OFC may degrade the transmitting signal quality & increases the error rates. The OFC systems design by considering the noise in optical communication links recently received great interest from researchers. In this paper, we first presented the OFC design with noises such as white Gaussian noise, shot noise, & thermal noise. Secondly, the impact of noises in OFC analyzed through simulation results by performing optical communications with & without noises. Third, to suppress the noise effects on optical communications, we propose the enhanced thresholding-based wavelet Denoising approach called Wavelet Denoising using Enhanced Thresholding (WDET). The aim of WDET for optical communications is to improve the signal quality & minimize the signal errors effectively in the presence of various noises. The design of WDET is based on the properties of hard & soft thresholding of wavelet Denoising. The simulation results show that the proposed Denoising approach improves the signal quality factor with reduced Bit Error Rate (BER) & Mean Square Error (MSE) compared to existing filtering methods

Transmission Control of Electromagnetic Waves by Using Quarter-Wave Plate and Half-Wave Plate All-Dielectric Metasurfaces Based on Elliptic Dielectric Resonators

We present the design of all-dielectric Quarter-Wave Plate (QWP) and Half-Wave Plate (HWP) metasurfaces based on elliptic dielectric resonators (EDRs) for the transmission control of electromagnetic waves over the frequency band 20–30 GHz. First, an extensive numerical analysis was realized by studying the effect of the resonators geometry (thickness and ellipticity) on the transmission of both x- and y-polarized waves. Then, based on the numerical analysis, we have realized and characterized experimentally both QWP and HWP all-dielectric metasurfaces

Etude et realisation d'un dispositif original pour traitement de surfaces par plasma micro-ondes

SIGLEINIST T 74830 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Multiscale Auxiliary Sources for Modeling Microwave Components

This chapter presents multiscale auxiliary sources mainly used to solve complex electromagnetic problems, especially those that insert localized elements into circuits. Several equivalence relations (field-circuit) are established to simplify and make more accurate electromagnetic calculations by changing some characteristics of the localized elements known by their field representation as “voltage-current” representation and vice versa. Various examples are illustrated to show the effects of auxiliary sources in planar circuits containing localized elements (dipoles, diodes, transistors) in the millimeter and terahertz bands. An example of a graphene or Gold dipole is demonstrated in this approach. Another typical example of a diode integrated in a radiating structure is also simulated

Intuition and Symmetries in Electromagnetism: Eigenstates of Four Antennas

Symmetries play an essential role in the field of physics. In this paper, we examine the relationship between the eigen-amplitudes of four (2 × 2) symmetrical antennas and the symmetry of the amplitudes of their sources (excitations) using mirroring effects. In our case, we find that changing mirrors using symmetry is identical to the point group theory. By exploiting the symmetry problem, we can show the advantage of reducing the size of the analysis domain, at least by a factor of two or more (2, 4, and 8…etc.) (depending on the problem). Several simulation examples have been developed by the MoM-GEC and HFSS to validate this approach

Radiation Pattern Synthesis of the Coupled almost Periodic Antenna Arrays Using an Artificial Neural Network Model

This paper proposes radiation pattern synthesis of almost periodic antenna arrays including mutual coupling effects (extracted by Floquet analysis according to our previous work), which in principal has high directivity and a large bandwidth. For modeling the given structures, the moment method combined with the generalized equivalent circuit (MoM-GEC) is proposed. The artificial neural network (ANN), as a powerful computational model, has been successfully applied to antenna array pattern synthesis. Our results showed that multilayer feedforward neural networks are rugged and can successfully and efficiently resolve various distinctive, complex almost periodic antenna patterns (with different source amplitudes) (in particular, both periodic and randomly aperiodic structures are taken into account). An ANN is capable of quickly producing the synthesis results using generalization with the early stopping (ES) method. Significant advantages in speed and memory consumption are achieved by using this method to improve the generalization (called early stopping). To justify this work, several examples are shown and discussed

Radiation Pattern Synthesis of the Coupled almost Periodic Antenna Arrays Using an Artificial Neural Network Model

This paper proposes radiation pattern synthesis of almost periodic antenna arrays including mutual coupling effects (extracted by Floquet analysis according to our previous work), which in principal has high directivity and a large bandwidth. For modeling the given structures, the moment method combined with the generalized equivalent circuit (MoM-GEC) is proposed. The artificial neural network (ANN), as a powerful computational model, has been successfully applied to antenna array pattern synthesis. Our results showed that multilayer feedforward neural networks are rugged and can successfully and efficiently resolve various distinctive, complex almost periodic antenna patterns (with different source amplitudes) (in particular, both periodic and randomly aperiodic structures are taken into account). An ANN is capable of quickly producing the synthesis results using generalization with the early stopping (ES) method. Significant advantages in speed and memory consumption are achieved by using this method to improve the generalization (called early stopping). To justify this work, several examples are shown and discussed