A General Method for Designing Highly Efficient Reflective Metasurface under Arbitrary Incidence

This letter presents a generalized method for designing highly efficient perfect anomalous reflective metasurfaces (PARMs) under arbitrary incident angles for 6G wireless communication. Being conventionally designed using gradient-phase method, these metasurfaces rely on the assumption of local periodicity and normal incidence. However, their performance can degrade at oblique incident angles due to angular dispersion and violation of phase-matching conditions. To address this, a theoretical framework that incorporates the angular dependence of both phase gradients and structural periodicity is established. In this work, the statistical deviations of the responses of local unit cells is modeled using the von Mises distribution, deriving the predistorted phase profiles that compensate for mutual coupling and structural perturbations. The proposed method is validated via design, simulation, fabrication, and measurement of four different PARMs at 155 GHz, achieving reflection efficiencies exceeding 88% with varying incident and reflection angles. The results confirm that this method generalizes metasurface design to a wider spectrum of configurations while substantially reducing the computational cost for arbitrary incident wavefronts, thereby facilitating efficient and scalable implementations in future reflective reconfigurable intelligent surfaces. © 2026 IEEE.