Two alternative approaches to the spatial spectral integral equation method are proposed. The first enhancement comprises a Hermite interpolation as the set of basis functions instead of the Gabor frame. The continuity, differentiability, equidistant spacing, and small support of these basis functions allows for an efficient and accurate numerical implementation. The second approach encompasses a method to transform between the spatial domain and the deformed path in the complexplane spectral domain. This method allows for more general path shapes, thereby removing the need to decompose the complex-plane spectral-domain path into distinct straight sections. Both enhancements are implemented for the case of TE polarization, and the results are validated against the finite element method and the rigorous coupled-wave analysis.
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