Time and frequency domain transformation to the far field with FDTD

Thefinite-difference time-domain (FDTD) algorithm could only calculate the fields offinite region. To get the far zone scattered fields, it needs transformation from near zone. In this paper the details of such a method are presented. The transformation technique can be applied to time domain or frequency domain. When transient or broadband frequency domain results are required, the time domain transformation is used. When the far fields at all observation angles are required, the frequency domain transformation is used.