Numerical modeling of a spherical array of monopoles using FDTD method

In this paper, the spherical-coordinate finite-difference time-domain method is applied to numerical analysis of phased array of monopoles distributed over a sphere. Outer boundary of the given problem is modeled by accurate spherical- coordinate anisotropic perfectly matched layer. The problem of increased cell aspect ratio near the sphere poles causing degradation of results is solved by dispersion optimization through artificial anisotropy. The accuracy of the approach is verified by comparing a model case with an exact solution. Finally, radiation patterns obtained by frequency-domain near-to-far-field transform and s-parameters of the array elements are presented and validated by comparing with measurement data.