An Efficient FG-FFT With Optimal Replacement Scheme and Inter/Extrapolation Method for Analysis of Electromagnetic Scattering Over a Frequency Band

In this paper, the replacement values to the singularity of fitting Green’s function are intensively researched in Fitting Green’s function Fast Fourier Transformation (FG-FFT) for different frequency points. As is shown in the research, the different replacement values caused the different accuracy of fitting Green’s function. The experiments show that an universal appropriate replacement value can improve the accuracy of the fitting Green’s function over the entire frequency band, and it is called the optimal wide-band replacement value in this paper. In the case of application of the optimal replacement scheme to FG-FFT, the number of the near correction elements is significantly reduced. Meanwhile, FG-FFT with the proposed scheme and interpolation method herein is used for wide-band analysis of electrically large objects to overcome the obvious error in FG-FFT with traditional replacement scheme and interpolation method. The near correction matrix elements can be interpolated over the entire frequency band with the new scheme, thereby achieving effective combination of the FG-FFT with matrix inter/extrapolation method, which greatly improved the computational efficiency for wide-band analysis.