Where to put excitation to find a radar cross section for an object?

Hi,

I want to find the radar cross section for an object. I set the excitation to a planewave excitation but the problem is that I do not know where I should put it.
Should it be in the far field or near field of the object. Does this incident field impact the RCS?

Thanks

Hello,

What program do you use?

I expect that you only have to specify direction (for the incident wave), as a plane wave implies infinite distance.

To make sure that everything goes well, first simulate a structure with known RCS.

I am using HFSS

I am not familiar with HFSS, hoping somebody else will have an answer.