Direction-Selective Wavefront Engineering with Asymmetric Metagratings

Bi-directional metagratings integrate direction-selective ("two-faced") wavefront engineering with the high-efficiency diffraction control of conventional metagratings. By loading two microstrip-based structures—each with independently engineered impedance—on opposite faces of a subwavelength dielectric slab, we achieve asymmetric electromagnetic responses: absorption under forward illumination and reflection under backward illumination. Full-wave simulations validate the design framework, exhibiting excellent agreement with theoretical predictions. The proposed bi-directional metagrating offer a versatile platform for asymmetric wave propagation and multifunctional communications in future systems.