A New Efficient FDTD Time-to-Frequency-Domain Conversion Algorithm

The time-to-frequency-domain conversion is often required in many applications of the finite-difference time-domain (FDTD) method.This paper presents a new FDTD time-to-frequencydomain conversion algorithm based on the optimization of nonuniform fast Fourier transform (NUFFT) with several redundancy-reduction techniques.The proposed algorithm can perform the FDTD conversion at multiple desired frequencies without the limitation of uniformly spaced frequencies in the fast Fourier transform (FFT).In addition, with a very low storage cost, the algorithm can be much more efficient than other FDTD conversion techniques if a moderate number of frequencies or more are of interest.This algorithm is very useful for some FDTD applications.