一种编码式宽带多功能反射屏

A wideband coding reflective metasurface with multiple functionalities

提出了一种可控的宽带多功能反射屏.通过将射频微机电系统技术与反射屏设计相结合,首先设计了可编码式工作的单元,该单元具有工作频带宽、损耗小、控制简单的特点.由该单元基于不同编码矩阵构成的反射屏可以实现不同的功能.文中展示了多功能反射屏的极化旋转和捷变散射场性能.仿真结果表明:设计的反射屏在8.9—13.2 GHz频段范围内极化转化率高达90%以上,且在8.9—13.1 GHz频段范围内可实现10 d B以上的雷达散射截面减缩.实测结果与仿真结果基本一致.

A controllable wideband multifunctional reflective metasurface is presented.First of all,a polarization-rotating unit cell is proposed by combing micro-electromechanical system（MEMS） technology with reflective metasurface design.The proposed unit cell is characterized by wideband,low loss and controllable properties.Each unit cell is integrated with two MEMS switches.When the two switches operate in different states,the unit cell shows different responses to plane wave incidence,and the corresponding working states can be denoted by ＂0＂ or ＂1＂.It is worth noting that a 180 degree reflection phase difference is generated for the two working states.Then,the proposed unit cell is periodically arranged to construct a metasurface.Based on different coding matrixes,multiple functionalities can be obtained by using the proposed metasurface.When all the unit cells are controlled to operate in on-or off-state,polarization-rotating function is obtained.Besides,the agility scattering field performance is also presented by using ＂chessboard＂ and ＂random＂codings.A series of equations is derived to reveal the relationship between reflection coefficient of the unit cell and radar cross section（RCS） reduction of the chessboard reflective surface,which is also verified by full-wave simulations.Finally,four prototypes consisting of 576-cells,which correspond to the ＂all 0＂,＂all 1＂,＂chessboard＂ and ＂random＂ coding,are fabricated and measured.The measured results demonstrate that the proposed reflective metasurface shows polarizationrotating performance in a frequency range of 8.9–13.2 GHz when all unit cells operate in ＂0＂ or ＂1＂ state.The measured results of the ＂chessboard＂ and ＂random＂ coding metasurface manifest remarkable RCS reduction compared with the same size metal plane.Good agreement between simulations and measurements is obtained.Owing to the ability to control polarization and beam shape of the reflected wave dynamically,the proposed reflective metasurface has potential applications in the field of intelligent stealth.