Applications of transformed‐space non‐uniform PSTD (TSNU‐PSTD) in scattering analysis without the use of the non‐uniform FFT

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AbstractIn this work, we extend the transformed‐space, non‐uniform pseudo‐spectral time domain (TSNU‐PSTD) Maxwell solver for a 2D scattering analysis. Prior to implementing the PSTD in this analysis, we first transform the non‐uniform grids {xi} and {yj} sampled in the real space for describing complex geometries to uniform ones {ui} and {vj}, in order to fit the dimensions of practical structures and utilize the standard fast Fourier transform (FFT). Next, we use a uniform‐sampled, standard FFT to represent spatial derivatives in the space domain of (u, v). It is found that this scheme is as efficient as the conventional uniform PSTD with the computational complexity of O(N log N), since the difference is only the factors of du/dx and dv/dy between the conventional PSTD and the TSNU‐PSTD technique. Additionally, we apply an anisotropic version of the Berenger's perfectly matched layers (APML) to suppress the wraparound effect at the open boundaries of the computational domain, which is caused by the periodicity of the FFT. We also employ the pure scattered‐field formulation and develop a near‐to‐far‐zone field transformation in order to calculate scattered far fields. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 16–21, 2003