International Journal of Applied Electromagnetics and Mechanics - Volume 32, issue 2

Authors: Angiulli, G. | Tringali, S.

Article Type: Research Article

Abstract: In this paper a technique to protect the Method of Moments solution of the E-Field Integral Equation (EFIE) for the scattering by conducting body from effects of its internal resonances, is presented. This method is based on the evaluation of the numerical null space K of the discretized EFIE operator. In order to verify its effectiveness, results for the plane wave scattering from a perfect conducting cube are presented. It is shown that the proposed method …is able to give the correct value of the RCS even in presence of the interior resonances. Show more

Keywords: Electromagnetic scattering, boundary integral equations, interior resonances

DOI: 10.3233/JAE-2010-1065

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 32, no. 2, pp. 63-72, 2010

Authors: Pa, P.S.

Article Type: Research Article

Abstract: An intelligent design system was created that efficiently uses a magnetic force to assist in the discharge of the dregs from the electrode gap during electrochemical finishing of cylindrical surfaces. In the current experiment, the author used a cylinder-shape electrode supplied with a continuous and pulsed direct current in the electrochemical finishing. This study used Taguchi's Method to analyze the combination of optimal parameters. The experimental parameters use four factors and three levels to measure the …surface roughness of the magnetic-assistance in the electrochemical finishing. These four factors include electric current density, magnetic strength, distance between the two magnets, and rotational speed. For the design system, a high electric current density coupled with electromagnetic-assistance reduces the finishing time and mitigates the issues associated with dreg discharge. A small distance between two electromagnets or a large electromagnetic field produces a larger electromagnetic force enhancing the dreg discharge and subsequently improves the finish. A small tool-electrode diameter enhances electromagnetic-assisted electrochemical finishing. The average effect of the magnetic assistance was greater than the pulsed current while the machining time did not need to be prolonged by the off-time. Show more

Keywords: Electromagnetic-assistance, electromagnetic force, surface finishing, electrochemical finishing, system design, Taguchi's method

DOI: 10.3233/JAE-2010-1067

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 32, no. 2, pp. 73-83, 2010

Authors: Oussaid, Rachid

Article Type: Research Article

Abstract: In this paper, we present a theoretical study of plane waves in chiral media. We are particularly interested in designing and analyzing chiral devices to quantify their shielding effectiveness as a function of frequency. The typical shielding materials used in this study are copper, aluminium and steel. We have also conducted a comparative study between these different types of materials. Due to chirality, there is magnetoelectric coupling. The electric and magnetic shielding effects are shown to …be function of the three material parameters (ε, μ, κ). We found that, at normal incident angle, reflection occurs similar to that of isotropic medium. The cross-polarization effects caused by the chirality appear at oblique wave incidence. Show more

Keywords: Chirality, material, shielding effectiveness, electromagnetic compatibility

DOI: 10.3233/JAE-2010-1069

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 32, no. 2, pp. 85-95, 2010

Authors: Yang, Jiashi | Jiang, Shunong | Hu, Yuantai

Article Type: Research Article

Abstract: We propose to use attached end masses to introduce more design parameters and possible improvement of the performance of Rosen piezoelectric transformers operating with extensional vibration of rods. A one-dimensional model developed in a previous paper is used for a theoretical analysis to verify the concept. Numerical results based on the theoretical analysis are presented, showing the effects of the end masses.

DOI: 10.3233/JAE-2010-1071

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 32, no. 2, pp. 97-110, 2010

Authors: Chien, Wei | Huang, Chung-Hsin | Chiu, Chien-Ching | Li, Ching-Lieh

Article Type: Research Article

Abstract: This paper presents an image reconstruction approach for a 2-D homogeneous cylinder with arbitrary cross section in free space. The computational method combines the finite difference time domain (FDTD) method and non-uniform steady state genetic algorithm (NU-SSGA) to determine the shape and location of the scatterer with arbitrary shape. The subgirdding technique is implemented for modeling the shape of the cylinder more closely. The inverse problem is reformulated into an optimization problem and the global searching …scheme NU-SSGA with closed cubic-spline is then employed to search the parameter space. A set of representative numerical results is presented for demonstrating that the proposed approach is able to efficiently reconstruct the electromagnetic properties of homogeneous dielectric scatterer even when the initial guess is far away from the exact one. In addition, the effects of Gaussian noises on imaging reconstruction are also investigated. Show more

Keywords: Index terms – time domain inverse scattering, microwave imaging, FDTD, subgridding FDTD, NU-SSGA

DOI: 10.3233/JAE-2010-1070

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 32, no. 2, pp. 111-123, 2010