Lastly, a parallel FDTD method was also used to model another interesting coordinate transformation based device, an optical black hole, which can be characterised as an omnidirectional broadband absorber. In this paper it is shown that the enhancement factor of the local electric field in metal covered ellipsoidal nanoparticles embedded in a dielectric host. cylindrical shell of inner radius b, as shown in Figure 5.2.4. ![]() The finiteness of such a nano-device and its impact on the system dynamic behaviour was numerically exploited. The outer shell was similar to the target solid solution composition, slightly enriched in Bi, Sc and Ta, whilst the core approximated to (Na, K, Li)NbO3 and was responsible for the additional. The device has its potential in subwavelength imaging at optical frequencies. Furthermore, a parallel three-dimensional dispersive FDTD method was introduced to model a plasmonic nanolens. These new devices demonstrate super-absorptivity over a moderate wideband range, suitable both for microwave and optical applications. It was found that, by utilising inherent electric and magnetic losses of metamaterials, as well as additional lossy materials, perfect wave absorption can be achieved. Several ways to control and manipulate the loss in the electromagnetic cloak based on transformation electromagnetics were examined. Finally, more useful cloaking structures were proposed, which can operate over a broad frequency spectrum. (1.55) for a charge interaction with an independent (external) field, and a similarly structured formula (1.60), but with an additional factor 12, for the field induced by the charges under consideration. In Chapter 1, we have obtained two key results for the electrostatic energy: Eq. The limitations of all these devices were thoroughly studied and explored. 3.5: Electric Field Energy in a Dielectric. With a few modifications the method is able to simulate general media, such as concentrators and rotation coatings, which are produced by means of coordinate transformations techniques. ![]() It was demonstrated that perfect ``invisibility'' from electromagnetic cloaks is only available for lossless metamaterials and within an extremely narrow frequency band. Cylindrical shells have structural applications in many fields of engineering, and the loading is often symmetrical, especially in pressure-vessel applications. ![]() The proposed method can accurately model both lossless and lossy cloaks with ideal or reduced parameters. The subject of this chapter is the behaviour of thin elastic circular cylindrical shells when they are loaded by forces which are symmetrical about the axis of the cylinder. A novel radially-dependent dispersive FDTD algorithm was proposed and applied to simulate electromagnetic cloaking structures. During this PhD study, several finite-difference time-domain (FDTD) methods were developed to numerically investigate coordinate transformation based metamaterial devices.
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