Design of circularly polarized reflectarray antennas based on MoM analysis of multilayered periodic structures involving split rings

Abstract

An efficient software has been implemented for the analysis of the scattering by multilayered periodic structures containing concentric metallic split rings in the unit cell. The software is based on the Method of Moments (MoM) in the spectral domain. Edge singularity basis functions are used in the approximation of the current density on the split rings, which makes it possible a fast convergence of MoM with respect to the number of basis functions. Since the 2-D Fourier transforms of the basis functions cannot be obtained in closed form, judicious tricks are proposed for their efficient computation. The software has been used in the design of circularly polarized reflectarray antennas under the local periodicity assumption. The results obtained in the analysis of the antennas with our in-house software have been compared with results provided by CST, and good agreement has been found. Our software has proven to be around 25 times faster than CST.