A tunable encoder with circular dichroism and polarization encoding function based on a layered metastructure in the GHz range

(a) The schematic diagrams of the presented encoder, where Structure 1 is the absence of the MDL, and Structure 2 is the addition of the MDL. (b) the electric field ( E ) of the incident EWs, being at 45°to the - y -axis, is decomposed into the components E y and E x , where E x represents the TM waves, and E y denotes the TE one. • The designed encoder is capable of CD and polarization encoding based on a layered metastructure. • The designed encoder researches the effects of HO on MP and YIG. • The encoder can simultaneously implement CDs at a single frequency point and PCs from LPWs to RHCPWs or other polarization waves within a certain frequency bandwidth. • The encoder supplements the traditional polarization encoders, focusing on the polarization encoding within a certain frequency range. • The designed encoder provides excellent support for the precise control of PC with high application possibilities and few operational difficulties. In this paper, based on a layered metastructure, a tunable encoder capable of circular dichroism (CD) and polarization conversion (PC) is researched, which contains one common medium, magnetized plasma, and yttrium iron garnet (YIG). The linear polarization waves (LPWs) are elected as incident waves. The incident angle and external magnetic field intensity are θ and H O . A modulable dielectric layer (MDL), composed of YIG, is optionally added to the preceding item of the given metastructure, which owns a certain thickness. By adjusting the proper θ , H O , and adding the MDL, the CD can be obtained at a certain frequency point, where the right-handed circular polarization waves (CPWs) and left-handed CPWs have different reflections. Meanwhile, the LPWs can be converted to CPWs or other polarization waves in a specific frequency band. Furthermore, the θ and addition of the MDL are considered as the first and second logic levels, respectively, to form four logic codes, which can realize the PC from LPWs to CPWs or LPWs within the same specific frequency band. Hence, the designed encoder has a promising potential in the precise control of PC in the special bandwidth, which can provide excellent support for the research of tunable and diverse polarization splitters and selectors.