International Journal of Applied Electromagnetics and Mechanics - Volume 47, issue 1

Authors: Xu, Chunhua | Deng, Zhengdong | Xiong, Run | Deng, Feifan

Article Type: Research Article

Abstract: When using sub-cell algorithms to model the coupling of apertures with finite depth in the finite-difference time-domain (FDTD) method, time-step size is required to be reduced to avoid instability. In this work, a time-step program is proposed for the stable modeling of apertures with finite depth using sub-cell algorithms. A sub-cell area related time-step reduction coefficient is introduced to ease the steady reduction of the time-step size firstly. Then a modified algorithm is given for sub-cells …whose area is extremely distorted. Numerical results demonstrate that the proposed time-step program is an accurate and stable modeling of aperture coupling without resulting in significant time-step reduction. Show more

Keywords: Aperture coupling, FDTD method, stability, time-step program

DOI: 10.3233/JAE-140047

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 47, no. 1, pp. 255-262, 2015

Authors: Kumar, Jitendra | Gupta, Navneet

Article Type: Research Article

Abstract: In this paper, a theoretical and practical investigation on microwave dielectric materials for wideband dielectric resonator antennas (DRAs) is presented. Due to the variety of materials available to antenna designers, a proper technique to select the best possible material is required. In this paper Ashby's material selection methodology is used for dielectric material based antenna systems. Four primary performance indices, impedance bandwidth (BW), the size of the antenna (λ), radiation efficiency (η) …and resonance frequency (f_{0} ), are used to obtain the desired performance. The selection chart shows that Roger TMM10, (ε_{r} = 9.8) is the most suitable material followed by "Roger's TMM10i and RO3010" for DRAs to provide the best performance for wideband applications. Performances of antenna are verified with rectangular and hybrid design of DRA in terms of reflection coefficients, radiation pattern, gain and efficiency. Theoretical work is compared with the simulation and the close agreement between the two, confirm the validity of this study. Show more

Keywords: Ashby's methodology, material selection, dielectric materials, wideband, dielectric resonator antenna, wireless communication

DOI: 10.3233/JAE-140051

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 47, no. 1, pp. 263-272, 2015

Authors: Xi, Neng | Yang, Jia-Jun

Article Type: Research Article

Abstract: The severe drawback of slotted permanent magnet linear synchronous motor (PMLSM) is the detent force, particularly when accurate positioning and constant low speed is required for numerically controlled machine tool. In this paper, a novel short-armature slotted type multi-segment permanent magnet linear synchronous motor (MSPMLSM) is proposed and constructed to reduce the detent force. It consists of a proper shift of the multiple segments of iron core relative to the PMs. The detent forces of MSPMLSMs …with different number of segment are analyzed and simulated by finite element method (FEM). The proposed structure has been proved to be a very effective approach for the reduction of detent force. Then this paper presents the statistical and mathematical optimum design of a 3-segment PMLSM using response surface methodology (RSM) together with FEM to minimize the detent force. Full factorial design and steepest ascent method, one of the iterative search method, is proposed to establish optimal design area for applying RSM. Finally, the global optimal design is predicted and the optimally designed one is manufactured, and the numerical results and measured results are reported to validate the effectiveness of this proposed method. Show more

Keywords: Multi-segment permanent magnet linear synchronous motor, detent force, optimal design, response surface methodology, steepest ascent method

DOI: 10.3233/JAE-140069

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 47, no. 1, pp. 273-282, 2015

Authors: Zhang, Qi | Zhou, Bihua | Yang, Bo | Wang, Jianbao

Article Type: Research Article

Abstract: By applying the Crank-Nicolson (CN) scheme to the divided two parts of Maxwell's equations, an efficiency-improved hybrid implicit-explicit finite-difference time-domain (HIE-FDTD) method is proposed to analyze the electromagnetic problems with fine-scale structure. Numerical formulations of the proposed HIE-FDTD algorithm for a 2D TE wave are analytically derived. The HIE-FDTD method, although conditionally stable, allows for larger time-step size than the conventional FDTD method. Moreover, the numerical performance of the proposed method is …verified to be quite good by comparing it against the existing HIE-FDTD method. Show more

Keywords: Finite-difference time-domain (FDTD) method, hybrid implicit-explicit FDTD (HIE-FDTD) method, leapfrog, stability condition

DOI: 10.3233/JAE-140118

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 47, no. 1, pp. 283-291, 2015