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Abstract-A rigorous semi-analytical solution is presented for electromagnetic scattering from an array of circular cylinders due to an obliquely incident plane wave. The cylinders are illuminated by either TM z or TE z incident plane wave. The solution is based on the application of the boundary conditions on the surface of each cylinder in terms of the local coordinate system of each individual cylinder. The principle of equal volume model is used to represent cylindrical cross-sections by an array of circular cylinders for both dielectric and conductor cases in order to proof the validity of the presented technique.

Abstract-This paper presents a hybrid technique, which combines the desirable features of two different numerical methods, finite difference frequency domain (FDFD) and the method of moments (MoM), to analyze large-scale electromagnetic problems. This is done by dividing the computational domain into smaller sub-regions and solving each sub-region using the appropriate numerical method. Once each sub-region is analyzed, independently, an iterative approach takes place to combine the sub-region solutions to obtain a solution for the complete domain. As a result, a considerable reduction in the computation time and required computer memory is achieved.

Abstract-A rigorous semi-analytical solution is presented for electromagnetic scattering from an array of parallel-coated circular cylinders of arbitrary radii and positions due to an obliquely incident TM z plane wave excitation. In order to check the validity of this technique, the radar cross-section of a single coated cylinder, a linear array of cylinders, and an arbitrary position array of cylinders are calculated and compared with available data in the literature. Furthermore, the near field is calculated to prove the validity of the boundary conditions on the surface of any cylinder with obliquely incidence wave. As an application, circular metamaterial cylinders are used to show the effect of metamaterial characteristics in altering the forward and backward scattering and in focusing the near field around the objects. 286Henin, Al Sharkawy, and Elsherbeni

Abstract-The electromagnetic scattering from a 2D chiral circular cylinders, illuminated by either a TE z or a TM z plane wave, is investigated using an iterative scattering procedure. The developed formulation and the implemented code simulate different types of cylinders, where the cylinders can be made of anisotropic chiral material with uniform or non-uniform chiral admittance distribution, homogeneous isotropic dielectric material, perfectly conducting material or a combination of all of them. The technique applies the boundary conditions on the surface of each cylinder in an iterative procedure in order to solve for the field expansion coefficients. Numerical verifications are presented to prove the validity of the formulation before presenting the scattering from an array of chiral cylinders showing significant RCS reduction in forward or backward directions based on the selection of the chirality parameter.

A semi-analytical solution is presented to the problem of electromagnetic scattering from an incident plane wave on a rectangular strip. The strip is simulated by parallel circular cylinders, illuminated by either a TE or a TM incident plane wave.The solution is based on the application of the boundary conditions on the surface of each cylinder in terms of the local coordinate system of each individual cylinder. This technique is used to predict the radar cross-section of strips composed of dielectric, conducting, and chiral material with uniform or nonuniform chiral admittance distribution.

In this work, an iterative approach using the finite difference frequency domain method is presented to solve the problem of scattering from large-scale electromagnetic structures. The idea of the proposed iterative approach is to divide one computational domain into smaller subregions and solve each subregion separately. Then the subregion solutions are combined iteratively to obtain a solution for the complete domain. As a result, a considerable reduction in the computation time and memory is achieved. This procedure is referred to as the iterative multiregion (IMR) technique. Different enhancement procedures are investigated and introduced toward the construction of this technique. These procedures are the following: 1) a hybrid technique combining the IMR technique and a method of moment technique is found to be efficient in producing accurate results with a remarkable computer memory saving; 2) the IMR technique is implemented on a parallel platform that led to a tremendous computational time saving; 3) together, the multigrid technique and the incomplete lower and upper preconditioner are used with the IMR technique to speed up the convergence rate of the final solution, which reduces the total computational time. Thus, the proposed iterative technique in conjunction with the enhancement procedures introduces a novel approach to solve large open-boundary electromagnetic problems including unconnected objects in an efficient and robust way.

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