Optimization of Reconfigurable Intelligent Surfaces via a Polarization Consistent Path Loss Model for Sidelobe Level Reduction

In this work, we design a reconfigurable intelligent surface (RIS) through an analytical path-loss (PL) model, which describes its behaviour in both near- and far-field regimes. At first, we reconsider the well established path loss model for intelligent reflecting surfaces, which has been recently presented in the literature, in terms of polarization. In particularly, we introduce a piecewise function for the radiation element pattern, which varies according to the polarization of the incident field. Next, we combine an optimization algorithm and PL simulations for designing a RIS with reduced sidelobe level that is valid for both polarizations. By adding nulls in specific angles of the farfield scattering pattern we demand reduced lobe level over a wide range of angles.