It can be concluded from the above experiments that compared with both the AIM and IE-FFT, both the FG-FFT and P-FFT are more accurate and not sensitive to the Cartesian grid spacing size.
It is again seen from Figure 8 and Table 3 that the accuracy of both the FG-FFT and P-FFT is higher than that of both the IE-FFT and AIM.
The bistatic RCS curves obtained by the FG-FFT and P-FFT for different discretization granularities are all shown in Figure 9, and the preprocessing time for the FG-FFT and P-FFT is recorded in Table 4.
It can be known from Table 4 that the preprocessing time of the FG-FFT is obviously less than that of the P-FFT for different discretization granularities.
Besides, the preprocessing time of the VIE-FG-FFT is obviously less than that of the P-FFT for inhomogeneous nonmagnetic dielectric objects.