Harmonic-assisted electromagnetically induced transparency-like with multiband polarization insensitivity on metamaterials

In this work, we present the design and analysis of a dual-layered metamaterial structure exhibiting multi-band, polarization-insensitive electromagnetically induced transparency (EIT)-like effects. Through a combination of full wave simulations and multipole scattering theory, the underlying physical mechanism is identified as the coherent coupling between bright (dipolar) and quasi-bright (higher order harmonics) eigenmodes, facilitated by the generation and interference of higher order harmonics. A comprehensive parametric study elucidates the correlation between geometric dimensions and the spectral positions and quality factors of the resulting EIT-like windows. Experimental verification conducted in a microwave anechoic chamber confirms the simulated transmission spectra demonstrating agreement. Furthermore, the structure’s performance as a refractive index sensor is quantitatively assessed, revealing sensitivity and figure of merit. These findings demonstrated the potential of the proposed metamaterial for advanced applications in multi-frequency filtering and integrated photonic sensing.