Numerical analysis of scattering from echelette grating - Smoothing process on mode-matching method
Abstract
The mode-matching method is a general numerical method for diffraction problems in which the modal expansion of electromagnetic fields is matched to the boundary condition, as in the case of Dirichlet-type boundary condition. However, the difficulty arises in deriving an accurate solution for Neumann-type problems where the electric vector is polarized in the direction perpendicular to grooves (H-polarization). An infinitely long grating consisting of a perfect conductor with an arbitrary cross section is considered, assuming that the grating has a period one in the x-direction and is uniform in the z-direction. A smoothing procedure is proposed in which the modal expansion is matched to the boundary condition via an indefinite integral. This procedure is able to suppress the spectral spread and to analyze the problem of diffraction from an echelette grating. Numerical results indicate the problem of diffraction from a grating can be analyzed with sufficient accuracy even for the H-polarization by adopting the new smoothing technique.
- Publication:
-
Electronics Communications of Japan
- Pub Date:
- March 1977
- Bibcode:
- 1977JElCo..60...82Y
- Keywords:
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- Echelette Gratings;
- Electromagnetic Scattering;
- Numerical Analysis;
- Propagation Modes;
- Smoothing;
- Boundary Conditions;
- Boundary Value Problems;
- Diffraction;
- Dirichlet Problem;
- Electromagnetic Fields;
- Neumann Problem;
- Polarization (Waves);
- Physics (General)