== Simulating a Larger Parabolic Reflector ==
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[[Image:ART PARAB Fig29.png|thumb|left|640px| Geometry setup for the parabolic reflector with a pyramidal horn feed in EM.Tempo.]]
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This is a very large computational problem with a domain size of about 17λ<sub>0</sub> × 17λ<sub>0</sub> × 11λ<sub>0</sub>. The computational domain is terminated in convolutional perfectly matched layers (CPML) from all six sides. To keep the simulation manageable, a mesh density of 15 cells per effective wavelength is adopted. [[EM.Tempo]]'s mesh generator uses an initial tessellation of the physical structure to accelerate the Yee mesh generation. To get a smooth mesh of the curved surface of the paraboloid, a curved edge angle tolerance of 10° is used. A very large FDTD grid (550 x 548 x 350) is generated. The Yee mesh of the reflector-horn combination is shown in the figure below.
The FDTD simulation was run on the same ASUS laptop computer. The simulation involved a total of 105,490,000 Total cells and converged after 8,850 time steps. The total simulation time was 155 minutes including both the FDTD time marching loop and computation of the full 3D far-field radiation pattern at a resolution of 1° along both the azimuth and elevation directions.