While that CPU mode existed in that discontinued API, it’s meaningless to be used in GPU vs. CPU benchmark comparisons because it’s far from optimal.
You should just not use OptiX Prime anymore and definitely not on RTX boards.
For radio transmission ideas see this comment.
https://forums.developer.nvidia.com/t/sphere-intersection-with-ray-distance-dependent-radius/60405/6
Ignore what I said about the “cone spread angle” there. That should work without such a differential approach when considering the full reflection hemispheres. It’s just like a direct lighting algorithm with the receiver’s being the lights.