Frequency Reconfigurable and Multifunctional Metastructure Regulated by Nematic Liquid Crystal: Broadband Circular to Linear Polarization Converter

With the tunability of the nematic liquid crystal (NLC), a broadband frequency reconfigurable and versatile metastructure (MS) is proposed and theoretically investigated in this paper, combining circular-to-linear (CTL) polarization conversion (PC) and circular-to-circular (CTC) PC simultaneously. The MS is composed of two via-coupled modules, which can respond differently to the incident waves. Each module is connected utilizing a metal via a column, thus exceedingly enhancing the energy transmission and reducing the loss when transmitting. When the applied bias voltage (V-bias) is 0 V, the NCL molecules follow the initial orientation. The MS converts the incident right circular polarized (RCP) waves into linear polarized (LP) waves within 8.11-9.95 gigahertz (GHz) with a relative bandwidth of 20.38% and achieves the PC of left circular polarized (LCP) into RCP waves. As the V-bias reaches 20 V, the original operating interval reconfigures and shifts overall toward a lower frequency. The bandwidth of CTL is 7.66-9.02 GHz, and the CTC PC is broadened to 20.20%. Meanwhile, the structure justification is verified, and the inducing mechanism of PC is expounded. Possessing the merits of versatile collaborative processing and wide operating bands, such an MS is promising to be a polarization-controlled application candidate and enrich multifunctional designs.