Shifted equivalent sources and FFT acceleration for periodic scattering problems, including Wood anomalies

JOURNAL OF COMPUTATIONAL PHYSICS

卷:378

Article

Bruno, Oscar R.¹  Maas, Martin^2,3 

[1] Caltech, Comp & Math Sci, Pasadena, CA 91125 USA

[2] Univ Buenos Aires, Buenos Aires, DF, Argentina

[3] Consejo Nacl Invest Cient & Tecn, Buenos Aires, DF, Argentina

关键词: Wood anomaly;    Quasi-periodic Green function;    Rough-surface scattering;    Diffraction grating;    Boundary integral equations;    Ewald summation method;   

DOI  :  10.1016/j.jcp.2018.10.044

来源: Elsevier

【 摘 要 】

This paper introduces a fast algorithm, applicable throughout the electromagnetic spectrum, for the numerical solution of problems of scattering by periodic surfaces in two-dimensional space. The proposed algorithm remains highly accurate and efficient for challenging configurations including randomly rough surfaces, deep corrugations, large periods, near grazing incidences, and, importantly, Wood-anomaly resonant frequencies. The proposed approach is based on use of certain shifted equivalent sources which enable FFT acceleration of a Wood-anomaly-capable quasi-periodic Green function introduced recently (Bruno and Delourme (2014) [4]). The Green-function strategy additionally incorporates an exponentially convergent shifted version of the classical spectral series for the Green function. While the computing-cost asymptotics depend on the asymptotic configuration assumed, the computing costs rise at most linearly with the size of the problem for a number of important rough-surface cases we consider. In practice, single-core runs in computing times ranging from a fraction of a second to a few seconds suffice for the proposed algorithm to produce highly-accurate solutions in some of the most challenging contexts arising in applications. (C) 2018 Elsevier Inc. All rights reserved.

【 授权许可】

Free