Terahertz complicatedly curved 3D propagation phase metasurface with high aperture efficiency

The curvature of a metasurface (MTS) induces the diverging local normal vectors (DLNVs), which consequently lead to radiation pattern distortion. This study investigates the impact of DLNVs on the radiation characteristics of curved propagation phase (PP) MTSs. To the best of the authors’ knowledge, this is the first systematic exploration of DLNV effects in this context, and a robust correction technique is proposed to mitigate the resulting pattern distortion. Three curved PP MTSs with x- polarization are designed to validate the proposed technique, and the calculated, simulated, and measured results agree well. The simulated AEs for MTS-1 and MTS-2 are estimated at 16.1% and 21%, respectively. For the cylindrical MTS-3, the aperture efficiencies (AEs) reach 52.8% in simulation and 29% in measurement. The proposed design framework is versatile and can be extended to various arbitrarily curved 3D surfaces, providing promising solutions for high-speed aerospace platforms, wearable electronics, and next-generation conformal communication systems.