A SURFACE INTEGRAL-EQUATION APPROACH TO THE SCATTERING AND ABSORPTIONOF DOUBLY PERIODIC LOSSY STRUCTURES

The scattering and absorption of a doubly periodic array of absorbers, either placed in free space, backed by a perfect conductor or by a ha lf-infinite space with the same material properties as the elements fo rming the array, is analyzed with a surface integral equation approach (SIE). The use of a suitable periodic Green's function as kernel of t he SIE reduces the formulation of the problem to a single absorber. A set of equivalent electric and magnetic currents on the surface of the absorber is discretised using Glisson functions and the SIE is solved with Galerkin's method. The validity and flexibility of the SIE appro ach is exemplified by comparing numerical results with measurement dat a for a family of commercially available absorbers.