Analysis and optimization of doubly periodic matching dielectric structures with longitudinally nonuniform elements

The problem of plane electromagnetic wave scattering by doubly periodic structures with pyramidal and conical dielectric elements arranged on a homogeneous dielectric half-space modeling the surface of a lens antenna is considered. A hybrid projective method involving the method of coupled waves, method of projective mathing of fields on the boundaries of partial regions, and one-dimentional method of finite elements is proposed. The method avoids using excessive number of unknown coefficients of expansion taking place in the previous versions. Some numerical results characterizing both the effectiveness of the method itself and the properties of periodic dielectric structures with elements optimized for providing match of lens surfaces to free space are presented and discussed.