Electromagnetic Waves Excitation by Thin Impedance Vibrators and Narrow Slots in Electrodynamic Volumes

Linear vibrator and slot radiators, i.e., radiators of electric and magnetic type, respec‐ tively, are widely used as separate receiver and transmitter structures, elements of an‐ tenna systems, and antenna-feeder devices, including combined vibrator-slot structures. Widespread occurrence of such radiators is an objective prerequisite for theoretical analysis of their electrodynamic characteristics. During the last decades, re‐ searchers have published results which make it possible to create a modern theory of thin vibrator and narrow slot radiators. This theory combines the fundamental asymptotic methods for determining the single radiator characteristics, the hybrid an‐ alytic-numerical approaches, and the direct numerical techniques for electrodynamic analysis of such radiators. However, the electrodynamics of single linear electric and magnetic radiators is far from been completed. It may be explained by further devel‐ opment of modern antenna techniques and antenna-feeder devices, which can be characterized by such features as multielement structures, integration, and modifica‐ tion of structural units to minimize their mass and dimensions and to ensure electro‐ magnetic compatibility of radio aids, application of metamaterials, formation of required spatial-energy, and spatial-polarization distributions of electromagnetic fields in various nondissipative and dissipative media. To solve these tasks, electric and magnetic radiators, based on various impedance structures with irregular geo‐ metric or electrophysical parameters and on combined vibrator-slot structures, should be created. This chapter presents the methodological basis for application of the gen‐ eralized method of induced EMMF for the analysis of electrodynamic characteristics of the combined vibrator-slot structures. Characteristic feature of the generalization to a new class of approximating functions consists in using them as a function of the cur‐ rent distributions along the impedance vibrator and slot elements; these distributions are derived as the asymptotic solution of integral equations for the current (key prob‐ lems) by the method of averaging. It should be noted that for simple structures similar to that considered in the model problem, the proposed approach yields an analytic solution of the electrodynamic problem. For more complex structures, the method may be used to design effective numerical-analytical algorithms for their analyses. © 2015 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The demonstrative simulation (the comparative analysis of all electrodynamic charac‐ teristics in the operating frequencies range) has confirmed the validity of the pro‐ posed generalized method of induced EMMF for analysis of vibrator-slot systems with rather arbitrary structure (within accepted assumptions). Here, as examples, some fragments of this comparative analysis were presented. This method retains all benefits of analytical methods as compared with direct numerical methods and allows to expand significantly the boundaries of numerical and analytical studies of practi‐ cally important problems, concerning the application of single impedance vibrator, in‐ cluding irregular vibrator, the systems of such vibrators, and narrow slots.