Electromagnetic Resonance Modification Technique for Optimization of Polarization Conversion Performance in Metastructures

Electromagnetic resonance modification (EMRM) is a promising method for upgrading and optimizing metastructures (MSs) that convert polarization states. The present study offers comprehensive theoretical work to demonstrate that appropriate hole columns and slit structures can be effectively employed to improve the performance of polarization conversion MS, which, in turn, enhances polarization conversion rate (PCR) in defective bands. The variation of PCR at each step is calculated and investigated through the usage of reflection amplitude and phase; furthermore, the inferior resonant frequencies (IRFs) are discussed in detail. The equivalent circuit model and nonlinear coupling mode theory are used to systematically summarize the implementation mechanism of EMRM technology. We observe that the EMRM technique is capable of inducing and re-exciting the directivity, density, and intensity of the surface currents, which is supported by the electromagnetic (EM) field energy distribution. Our findings not only shed light on the operating mechanism of EMRM technology but also offer new avenues for designing ultrawideband and highly efficient polarization conversion MSs.