Highly Efficient Decoupled Triple‐Channel OAM Generation with a Single‐Layer Shared Aperture Reflective Metasurface

Abstract

physical degrees-of-freedom (Dof ) for EM wave. [2] Accordingly, OAM technology has attracted much attention in the fields of optics, [3] terahertz, [4] millimeter-wave, [5] and microwave [6] communications. However, the conventional OAM generation devices (e.g., spiral phase plates, [7] phased array [8] ) are difficult to integrate multiple Dof of EM waves, which cannot meet the demand of high information capacity for satellite communication [9] (SatCom) on-the-move, [10] supermassive multipleinput multiple-output (SM-MIMO), [11,12] and physical layer security in 6G. [13,14] Metasurfaces show great flexibility in manipulating the amplitude, phase, and polarization state of EM waves, making them excellent platforms for vortex beam generation, [15] holography imaging, [16] beam convergence, [17] beam scanning, [18] etc.. In recent years, metasurface-based highly integrated multichannel multiplexing (e.g., frequency-polarization multiplexing) is the general trend for modern wireless communication to realize high information capacity. [19] Many metasurface-based OAM generator have been proposed, which are realized by singlepolarization frequency multiplexing, [20,21] single-band polarization multiplexing, [22,23] dual-linearly polarized (LP) dual-band techniques, [24,25] dual-circularly polarized (CP) dual-band techniques, [26,27] as well as active components loading. [28,29] Nevertheless, these metasurfaces are limited by LP-only or CP-only modulation, which neglect the joint multiplexing of LP-OAM and CP-OAM to further enhance channel capacity. Subarray, [30] radial stitching, [31] and multilayer [19] techniques have been used to achieve independent multiplexing of LP and CP in two different bands. Nonetheless, the commonly used Pancharatnam-Berry (PB) phase meta-atoms for CP channel rely on dynamic rotation to manipulate wavefront, which tend to compress the available space of the lattice and are prone to footprint collisions with LP subunits. The last two year studies on noninterleaved metasurface [32] and chiral-assisted geometric-phase metasurface [33] also have the unavoidable dynamic rotational properties of the meta-atoms. So, the CP and LP subunits of current multifunctional metasurfaces can only be staggered on a single-layer lattice to avoid collision with each other, which is Metasurface is extensively studied for generating multicharacteristic orbital angular momentum (OAM) beams. However, designing a highly integrated and independent polarization-frequency multiplexing metasurface for efficient multiscenario OAM-related applications is still a challenge. Here, a triple-band single-layer shared aperture reflective metasurface for triple-polarization channels independent OAM modulations is proposed. The specific frequency quantitative customization resonance phase and quasi-static geometric phase are utilized to manipulate the dualband (Ku-and K-band) orthogonal linearly polarized (LP) channel and C&Xband right-handed circularly polarized (RHCP) channel. An isolation ring is introduced for eliminating t...

Single-Layer Programmable Metasurface for Manipulating Both Linearly and Circularly Polarized Electromagnetic Waves

“…Metasurfaces, a kind of two-dimensional artificially structured materials, − are engineered to obtain properties that have not yet been found in nature and have emerged as promising candidates for electromagnetic wave manipulations. − Owing to the unprecedented opportunities to manipulate electromagnetic characteristics, a variety of metasurfaces with different functions have been investigated and realized, such as absorber, , polarization converter, , OAM generation, − and wireless power transfer . However, the functionalities of these metasurfaces rely on the variations of the physical structures of meta-atoms, which are typically fixed once designed or fabricated.…”