Fast FDTD/TDPO Hybrid Method Based on Spatiotemporal Sparse Sampling

Based on a hybrid method of finite-difference time-domain (FDTD) and time-domain physical optics (TDPO), this study employs a sparse sampling technique in near-to-far-field calculations to improve the efficiency of electrical large target computation. In the conventional hybrid method, the transformation from the near-field of the FDTD region to the far-field of the TDPO region involves the largest amount of computation, which can be reduced by applying the sparse sampling optimization method jointly in spatial and time domain. Compared to the conventional method, our proposed algorithm significantly reduces computation time while maintaining a negligible increase in error. Several examples are provided to demonstrate the accuracy and efficiency of our approach. In particular, a large parabolic antenna whose aperture size is 100 wavelengths is computed. The computation time is decreased by up to 91.52% of the conventional method while the maximum relative error is -21.56 dB. Compared with results of CST software, the method proposed in this work has smaller errors and excellent applicability.