Theoretical reflection coefficient of metal grid reflectors at a dielectric interface

Reflection properties of square apertures metal mesh mirrors are studied th eoretically with the Finite-Difference Time-Domain (FDTD) method associated to Floquet Boundary Conditions. The reflector is illuminated by a normally incident plane wave and is located at an interface between two semi infini te low loss dielectric materials. Reflectivity and phase of the reflection coefficient are given in the non diffraction region for a wide range of squ are apertures, and for the four situations corresponding to an interface be tween free space and fused quartz.