Wavefront manipulation based on mechanically reconfigurable coding metasurface

Abstract

In this paper, we propose a mechanically reconfigurable coding metasurface for wavefront manipulation to modulate the scattering beams as desired. The phase pattern on the coding metasurface can be harnessed by mechanically adjusting the thickness of the air substrate using four precise stepper motors. When the coding metasurface is illuminated with a plane wave, the magnitude of the scattering beams can be manipulated as desired. In addition, by applying specific coding series, different radiation modes of the coding metasurface can be realized by mechanical manipulation. To realize these functionalities, a square patch unit cell with an air substrate is employed here. The metallic patterns of metasurfaces are fabricated via Flexible Printed Circuit (FPC) technology, whose inherent property is conformality, implying a broader range of potential applications. To demonstrate our schemes, three metasurface patterns are designed and simulated. Two of them are fabricated and measured, showing good agreement with our simulations. Compared with other methods of tunable coding metasurfaces, the mechanically coding metasurface yields lower system complexity, lower cost, and easier fabrication. Besides, flexibility, the intrinsic specialty of FPC, enables the proposed metasurface unparalleled applications, such as security imaging, medical sensing, and various wearable devices.