Single-Layer 1-Bit Prephased Single-Beam Metasurface Using True-Time Delayed Unit Cells

A single-layer prephased 1-bit reflective metasurface is proposed to achieve single-beam radiation patterns under normally incident plane waves. By integrating the true-time delay lines with the prephase technique, the proposed design resolves the inherent symmetric beam issue of the conventional 1-bit reflective metasurface design in a single-layer design. To verify the proposed design, three 1-bit reflective metasurfaces comprising 20 × 20 unit cells with single beams pointing separately at $-15^{\circ }$, $15^{\circ }$, and $30^{\circ }$ are designed and measured over frequencies of 35.0–43.0 GHz. Simulated and measured results show that the proposed prephased 1-bit reflective metasurface can achieve single-beam patterns under normally incident plane waves using only one layer.