Anisotropic and nonlinear metasurface for multiple functions

Abstract

We present a novel anisotropic and nonlinear metasurface integrated with multiple functions of diffuse scattering, beam splitting, and normal reflection, which can be switched in real time by tuning the polarization state or power level of the incident microwave. The key lies in the two judiciously designed anisotropic nonlinear particles in subwavelength scales that possess opposite reflection phases under one polarization and the same nonlinear power-dependent reflection phases under the orthogonal polarization. These properties are demonstrated comprehensively via comparisons between their reflection responses, receiving abilities, and nonlinear circuitry behaviors. In addition, both the spatial arrangement and the electrically enabling strategy of the particles are underpinned to pursue the proposed functions, which are verified through numerical simulations and measurements. When the metasurface is illuminated by plane waves coming from the direction perpendicular to it, a significant beam splitting effect is achieved with strong x-polarized incidence, which is switched to a specular reflection when the incoming power decreases. Under y-polarization, a diffuse scattering phenomenon is obtained, which is not dependent on the incident intensity. The study is expected to offer new solutions to many electromagnetic scenarios involving energy transmissions and protections.

Compact Design of a Transmission‐Type Reconfigurable Intelligent Surface System for Beam‐Steering Applications

“…[5][6][7][8] Because they can be easily integrated with tunable components, reconfigurable features can thus be developed, making it possible to combine digital controlling techniques and realize reconfigurable intelligent surfaces (RISs). So far, a wide range of advanced applications have been propelled by the RIS, such as beam manipulations, [9,10] smart imaging, [11,12] wireless communications, [13][14][15] backscattering communications, [16] wireless power transfer, [17] target tracking, [18] nonreciprocity, [19,20] to name a few.…”

Reprogrammable Nonlinear Transmission Controls Using an Information Metasurface

“…The metamaterial has unique and novel characteristics, which provide a new way to realize the nonlinearity in the microwave field, including frequency mixing, [19,20] nonreciprocal transmission, [21][22][23] harmonic generation, [24][25][26][27] resonant tuning, [24,[28][29][30][31] and polarization conversion. [32] In recent years, significant progress has also been made in nonlinear metasurfaces by employing active devices, such as nonreciprocal transmission, [33][34][35][36] intensity dependent nonlinear reflection, [37,38] nonlinear absorption, [39,40] intensity dependent beam scanning, [41] energy selective surface, [42,43] new frequency generation using time encoding. [27,[44][45][46][47] However, combining metasurfaces with amplifiers and utilizing controllable nonlinear characteristics of the amplifiers to achieve editable nonlinearities of the metasurfaces have not yet been presented.…”

Amplification and Manipulation of Nonlinear Electromagnetic Waves and Enhanced Nonreciprocity using Transmissive Space‐Time‐Coding Metasurface

“…[42] Another advanced nonlinear manipulation of EM waves via transistor-based metasurfaces has been reported. [43][44][45] Combining metasurface with amplifiers could bring new physical characteristics, nonreciprocity, which has the advantage of lower volume compared with conventional magnet devices. Moreover, this makes it possible to integrate with semiconductor technology, appropriate in the microwave and millimeter-wave regime.…”