Analysis of a periodic dielectric layer loaded with metallic strips by FD-MEI technique

The analysis of frequency selective surfaces (FSS) is of great importance in theory and practice. The finite difference (FD) method with the measured equation of invariance (MEI) is first applied to the electromagnetic scattering analysis of a periodic dielectric layer loaded with metallic strips. The FD equations are used at the interior nodes of the mesh for a unit cell, and the MEI is applied at the upper and lower truncated boundary nodes. Equivalent currents on the surfaces of the periodic structure are assumed as the metrons in terms of the Floquet-type modes, which are used for measuring the undetermined coefficients in the MEI. The MEI may absorb not only the dominant Floquet´s mode but also the high order modes, so the truncated boundaries may be very close to the surface of the periodic structure. The geometry dealt with can involve an arbitrarily shaped cross-section for the periodic dielectric layer and a random starting allocation for the loaded metallic strips. The numerical results are in good agreement with the results in the available references.