AbstractHaving published two Special Issues on Optics in 2013 the Journal of Microwaves, Optoelectronics and Electromagnetic Applications is publishing another Special Issue on Modelling, Characterization and Application of Materials in Electromagnetism this year 2014. This reflects the growing importance and often key role of new materials for practical applications in science and industry and the need of an appropriate formulation of their sometimes very complicated but useful characteristics. It can also be seen that Brazilian research groups working on these topics, in high frequency as well as in low frequency areas have enormously matured during the last 25 years and can be on a par with internationally high ranked groups of other countries. In this context I want to mention that the highly accepted International Conference on the Computation of Electromagnetic Fields (COMPUMAG) Â took place already two times in Brazil.Â In detail this Special Issue highlights some selected topics. So in one paper some characteristics of a magnetostrictive material (Terfenol-D) using Fiber Bragg Grating to determine the strain of the material are presented, showing that they have to be taken into account in the development of magnetostrictive sensors. Another paper is on the highly important metamaterials, deriving a corrected version of the Maxwell-Garnett model for the homogenization of magnetic material structured with cylindrical nanorod inclusions. The way of solution shows that it can be sometimes more effective to introduce new formulations dedicated to the special problem than applying a standard method of Computational Electromagnetics. In another paper a simulator of nonuniformities in twisted-pair cables is presentedÂ whichÂ reproduces how electrical quantities like impedance or frequency response are affected by nonuniformities due to handling and imperfections of the manufacturing process. As shown by comparison with measurements the simulator accurately predicts effects like resonances and increase in impedance. Directional Coupling is accounted for by a paper on aÂ new design of an optical fiber coupler constituted by two and three cores based on Step Index Holey Fiber (SIHF) Â Â and analyzed by an efficient Vectorial Beam Propagation Method (VBPM) in conjunction with Genetic Algorithm (GA). Some phenomenon with materials can be described by Computational Electromagnetics, some better by measurements and some by both. The latter is shown by a workbench beingÂ able to evaluate the quality ofÂ the stator core in terms of the magnetic material, dimensions, as well as manufacturing faults as short-circuit on laminations. This new tester submits the sample to magnetic flux closer to a real machine than traditional testers.Â Â The evaluation of hysteresis losses remains a topic for further research, particularly in electromagnetic devices under non sinusoidal induction wave-forms. The originality ofÂ one of the related papers lies on the fact that it is not necessary to perform Fourier Transform of the applied waveforms,as it is usually presented in the literature to calculate the hysteresis losses with simplified methods. The needed parameters are extracted automatically from the original applied induction waveform using a cycle counting algorithm developed by the authors. I would like to thank to all authors for submitting papers, to the reviewers and in particular to the JMOe Editor, Renato Mesquita, for having invited me to organize this Special Edition.
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How to Cite
Arnulf Kost. (2014). FOREWORD. Journal of Microwaves, Optoelectronics and Electromagnetic Applications (JMOe), 13(SPECIAL IS), -. Retrieved from http://www.jmoe.org/index.php/jmoe/article/view/450