Design of Multiband Unit Cell for Binary Reconfigurable Intelligent Surfaces

This paper introduces a novel unit cell able to provide dual band operation for binary Reconfigurable Intel-ligent Surfaces (RIS). The operating bands are at 1.67 and 4.28 GHz with narrow bandwidths of 100 MHz approximately. The proposed cell shows stability with respect to variation in the incidence angle up to 30 deg for the TE polarized waves. To assert the wave control function, simulations are done for a full surface with size 12λ × 16λ and the deflected beams are calculated at the two bands.