Dual-Layer Coupling Enhanced Complementary Metasurfaces for 1-bit Terahertz Beam Steering

In addressing the challenges of independent control and low efficiency in single-layer structures for terahertz (THz) electrically-controlled encoding metasurfaces, this paper presents a novel 1-bit independently-controlled reconfigurable intelligent metasurface integrated with high electron mobility transistor (HEMT) heterostructures. By modulating dual-layer coupling on complementary hexagonal ring resonators by HEMT, the reflection efficiency and phase shift bandwidth are effectively enhanced. Within the frequency range of 0.32-0.37 THz, the metasurface exhibits unit insertion loss of less than 5 dB within a phase shift range of 180±30 °, and a beam scanning range exceeding 120°. The proposed dual-layer complementary coupling-enhanced THz HEMT reconfigurable metasurface offers an effective technological approach for realizing large-scale, highly integrated THz reconfigurable intelligent surfaces (RIS), holding significant application value in THz wireless communication, imaging, and radar detection systems empowered by RIS.