Array Scattering Synthesis for Anomalous Deflection Using Passive Aperiodic Loadings

Large-scale anomalous reflectors in reconfigurable intelligent surface applications require a scanning capability to deflect the beam to an arbitrary angle without incurring parasitic scattering. In this study, we propose a design methodology for linear loaded antenna arrays by synthesizing the scattering characteristics with respect to impedance loads to attain perfect anomalous reflection. It relies on accurate prediction of the induced element port currents and their associated scattering behavior for any given set of load impedances. We develop a linear array with a fixed half wavelength spacing for scanning into extreme deflection angles. Using continuous and discretized load reactances, the tunability prospect of high-efficiency anomalous reflection is demonstrated.