METHODS AND APPARATUS FOR CALCULATING ELECTROMAGNETIC SCATTERING PROPERTIES OF A STRUCTURE AND FOR RECONSTRUCTION OF APPROXIMATE STRUCTURES

摘要

A method of calculating electromagnetic scattering properties of a structure, the structure including materials of differing properties and the structure being periodic in at least one lateral direction and extending in a vertical direction, comprises: numerically solving a volume integral equation for electromagnetic scattering for a plurality of modes in the at least one lateral direction, by performing, for each respective mode, integration (1350) of a pseudo-spectral polynomial (Chebyshev) expansion in the vertical direction multiplied by a ID Green's function using the same sample points in the orthogonal direction for all of the plurality of modes. The integration is performed by solving a regularized linear system of equations between first (1116) and second (1120) discrete transformation steps to compute (1118) values of a regularized Chebyshev expansion coefficient vector (γ). Electromagnetic scattering properties of the structure are calculated using the results of the numerical solution.

主权项

1. A method of calculating electromagnetic scattering properties of a structure, the structure including materials of differing properties and the structure being periodic in at least one lateral direction and extending in a direction orthogonal with respect to the at least one lateral direction, the method comprising:
numerically solving a volume integral equation for electromagnetic scattering for a plurality of modes in the at least one lateral direction, by performing, for each respective mode, integration of a pseudo-spectral polynomial expansion in the orthogonal direction multiplied by a 1D Green's function using the same sample points in the orthogonal direction for all of the plurality of modes, wherein the integration is performed by solving a regularized linear system of equations; and calculating electromagnetic scattering properties of the structure using results of the numerical solution.