Investigation of the influence of dielectric material properties on a magnetically actuated MEMS-based THz metasurface

Abstract

This paper presents a device sensitive to dielectric material properties, based on a square shaped split-ring resonator (SRR) metasurface operating in the terahertz (THz) frequency band. In the proposed structure, most of the single resonant element is anchored in a silicon substrate, while the remaining part is movable (a magnetic-material-based free-standing cantilever) and can be deformed by an external magnetic field. Owing to its variable geometry, these micro-electro-mechanical systems (MEMS) constitute a reconfigurable resonant element. The structure is designed and analyzed using finite element method (FEM) numerical modeling. The analytical model is presented using an equivalent electrical circuit model. The resonance behavior (at 0.38 THz and 1.13 THz under zero-deflection conditions) is investigated for dispersive, non-dispersive gaseous and liquid material sweep, and a parametric analysis is performed for various deflection levels. This model-based analysis shows that frequency shift of the tunable metasurface sensor, under external material influence and different deflection levels, has potential for sensing (based on detecting changes in the effective permittivity ( ε _eff )) and non-destructive testing applications. This analysis makes the path for future fabrication and experimental validation.