Analysis of the shielding performance of 2-D periodic screens against near sources

The objective of this paper is to investigate the use of periodic artificial materials for shielding high-frequency high-impedance near fields produced by electric dipoles. The problem is handled numerically by applying the Array Scanning Method that reduces the problem of an aperiodic source close to a periodic screen to a superposition of phased-dipole-array problems (where the array periods are the spatial periods of the shield). As a result, the Floquet theory can be applied and the scattering problem is solved in the unit cell by means of a periodic space-domain Method of Moment, which employs the Ewald transformation to compute the involved Green´s functions with accelerated performance. The exact solutions are compared with those derived by a spectral-domain approach with the use of homogeneous models and by the classical transmission-line approximation.