The single sided MS was modeled using master-slave periodic boundary conditions in the x and y directions of the unit cell of Fig. 1. The periodic boundaries enforce a linearly progressive phase shift between the master and slave boundary pairs with uniform amplitude to enable beam scanning in the required directions. Two Floquet ports were used to illuminate both sides of the MS, one located at the top face and the other at the bottom face of the model’s air box. The length of the airbox was chosen to ensure that all higher order modes other than the two propagating zeroth-order Floquet modes experience at least 70 dB of attenuation.