Reply To: What theory uses Lumerical to compute farfield ?

[Kirill]

Hello Paul,

The FDTD far-field approach is based on the radiation integral; see the article Far field projections in DGTD overview. Although the article focuses on DGTD, the principle of far-field projection remains the same.
For more details on the method, you can refer to the following chapter: Chapter 14: Far-Field Transformations.

Best regards,
Kirill