Analysis of single layer multiple concentric ring elements in reflectarray antennas

In this paper, multiple concentric rings are considered as phase elements in reflectarrays and the benefits of these single layer rings are compared to conventional reflective structures (multi and single layer, rectangular or elliptical printed patches) when applied to the design of reflectarrays. These ring-shaped structures have got, as the main advantages, the ease of manufacture and the wide range of phase obtained, exceeding easily 1000 degrees. The analysis of the structures is made by means of the CG-FFT method. The simulations are carried out in the Ku band, the one commonly used in Direct Broadcast Satellite applications (DBS). In order to determine the effect of the manufacturing tolerances, results of a test carried out with a simulated reflectarray are included, using a PSO based algorithm to perform the phase synthesis.