基于手性超构表面的双频带极化转换器设计

Design of dual-band polarization converter based on chiral metasurface

摘要:

为满足宽频带、高极化转换率(polarization conversion ratio,PCR)和小型化极化转换器的应用需求,本文设计一种基于手性超构表面的双宽频带、高PCR的透射型极化转换器,其由顶层、底层开口环和中间介质基板的三层复合结构组成。仿真结果表明,该超构表面在6.21—7.05 GHz和8.74—9.73 GHz频率范围内均可实现线极化波的转换,PCR均超过90%,相对带宽分别为12.70%和10.72%。通过分析谐振频率处的表面电流,揭示其高PCR和双频带极化转换机理。此外,探讨超构表面的几何参数、介质层厚度、入射波极化方式和极化角度等参数对双频带极化调控特性的影响规律。所提出的基于手性双频带极化转换超构表面具有结构简单、极化不敏感等优点,在微波通信、显微成像、隐身技术等领域具有潜在的应用价值。

Abstract:

To address the application requirements of wideband,high polarization conversion ratio (PCR) and miniaturized polarization converters,a dual- wideband and high PCR transmissive polarization converter based on chiral metasurface is designed in this paper.The proposed polarization converter consists of a three-layer structure:open rings at the top and bottom layers and a dielectric layer.The simulation results show that the metasurface uniformly achieves linear polarization conversion in the frequency ranges of 6.21—7.05 GHz and 8.74—9.73 GHz with the PCR value all exceeding 90%,and the corresponding relative bandwidths are 12.70% and 10.72%,respectively.The mechanism of high PCR and dual-band polarization conversion is revealed by analyzing the surface currents at the resonant frequencies.In addition,the influence of geometric parameters,thickness of the dielectric layer,polarization mode and polarization angle of the incident wave on the polarization manipulated characteristics of the dual-band are also studied.The proposed chiral dual-band polarization conversion metasurface possesses the advantages of simple structure and polarization insensitivity,which has potential application values in microwave communication,microscopic imaging and stealth technology.