Analysis of Essential Structures

In this section, the higher order FDTD methods are applied to basic three-dimensional (3-D) radiation and scattering problems that involve simple dipole antennas. As performed in Chapter 7, whenever possible numerical results are compared to reference data, alternative formulations are also taken into account. 

Let us examine a radiation problem involving a perfect electric conducting (PEC) sphere of radius rs centered in a free and lossless space. The structure is excited by an electric dipole source at (0, 0, z = Zo rs) and is polarized along the z-direction. Its temporal profile is given by the smooth function of 

FIGURE 8.1 (a) Transverse cut of the computational space with the PEC scatterer terminated by a spherical PML. (b) Normalized electric field Er component of the z-polarized electric dipole 

Finally, numerical verification investigates an elliptical structure. Specifically, a 3-D domain in the presence of an elliptical-cylindrical lossy scatterer with a height of 0.75 m and 

FIGURE 8.2 (a) Numerical reflection coefficient versus frequency for a two-cell scatterer-PML distance. (b) Convergence of global error versus grid resolution 

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