Study on Spectral-Domain Formulation of Electromagnetic Scattering by Periodic Strip Array with Period Modulation

This paper considers the two-dimensional electromagnetic scattering from strip gratings with period modulation, and shows a spectral-domain technique based on the rigorous coupled wave analysis (RCWA). The RCWA is one of the most commonly used numerical analysis method for the perfectly periodic structures in optics. The present formulation introduces the pseudo-periodic Fourier transform to make the RCWA possible to apply to the problem of imperfectly periodic structure.