RL-GO for a Gradient-Index (GRIN) Lens

Hi Torben,

In the attached I am trying to model a Gradient-Index (GRIN) lens using RL-GO ray tracer as the MoM-MLFMM surface equivalence solver can't model this lens due to memory constraints. The diameter of the lens is greater than 20 lambda which should be ideal for ray methods. The lens is defined using many volumetric regions with a unique dielectric constant. The lens is illuminated by a spherical wave expansion source. In order to validate the accuracy of the RL-GO solver the permittivity of the lens was set to be equal to free space and near field data was computed on a planar grid.    

TThe RL-GO near field data must match the FEKO simulation with no lens case, but there is a huge discrepancy in the RL-GO result. I have attached both the .sph file and cadfeko model for your reference.  I tried adaptive ray launching accuracy option high but there is nno significant improvement in the accuracy of the solver.

Can you have a look at the model and let me know if the GO solver can handle these type of lens.