APPLICATION OF FINITE-DIFFERENCES TO THE ANALYSIS OF DIFFRACTION GRATINGS EMBEDDED IN AN INHOMOGENEOUS AND LOSSY DIELECTRIC

Diffraction of plane monochromatic radiation by an infinite array of perfectly conducting cylinders is analyzed by a finite-difference coupling technique. The cylinders have arbitrary cross-section and are embedded periodically in an inhomogeneous and lossy dielectric. The obliquely incident radiation is of linear polarization with either of its fields parallel to the axis of the cylinders. The method is simple in nature and involves no unchecked approximations. Numerical results are obtained for gratings with circular elements embedded in inhomogeneous and/or lossy dielectric. The power of the method for handling the problem is demonstrated. Some transmission and reflection characteristics of the gratings are brought out and their applications discussed.