An Efficient cascaded filter form of a 3D-FDTD TF/SF and a Mixed FFT/circulation convolution

In this paper we will propose an efficient 3D Total-Field Scattered-Field (TF/SF) to resolve the memory storage issue facing the existing AFP (analytic field propagator) methodology. We solve this challenge by first proposing an optimized AFP grid derivable from the rational angle propagations. This optimized grid, in turns, allows us to construct an efficiently FFT to circular convolution conversion using a cascaded filter formation, hence reducing the memory storage without seriously damaging the computational complexity. We also introduce complex projection angles and avoid computing both E^rarr and H^rarr in frequency to show that the incident field appearing at the SF region can be suppressed by -300 dB.