To predict the radiation patterns of the antenna using the finite
difference time domain (FDTD) method, the cell sizes were defined as
Ax = Ay = 0 615 mm and Az = 0.4 mm.
The perfectly matched layer
(PML) introduced by Berenger [5] was applied as the absorbing
boundary conditions (ABCs) located 10 cells far from the antenna
structure.
The frequency-domain near-field to far-field (FD-NFFF)
dansformation [6] was used to obtain the far-field pattern at the
design frequency The near-field to far-field transformation surface
was five cells from the antenna structure