FavoriteSimulation Antenna Magus CST Studio Suite 

My favorite simulation would be that of the Luneburg lens. I did the simulation while developing the design algorithm for a Luneburg with rectangular horn feed in Antenna Magus.

The Luneburg lens is a spherical symmetric gradient-index (GRIN) lens. GRIN lenses are characterized by a gradual variation in the refractive index of the lens. Luneburg’s solution for the refractive index ensures that any ray emanating from a point on the surface of the lens will emerge at the opposite side as a parallel beam. The theory requires the permittivity to vary continuously from the centre to the surface of the spherical lens. Since continuous variability is difficult to realize in practice, manufactures use multiple (between 6 and 9) concentric shells with discretely varying permittivities.

Due to its symmetry, multiple beams in arbitrary directions can be formed.

The reason I like this simulation is that you can visually confirm that the design is working. You can see how the spherical E-field radiating from the horn is focused as it moves through the lens and exits as a plane wave.

If you have Antenna Magus, make your own design, export the model to CST Studio Suite, add an E-field monitor and see for yourself!

​​​​​​​
​​​​​​​