Plasmonic hybridization in symmetric metamaterial for broadband negative refractive index: simulation, experiment and characterization

This work demonstrates a broad-band negative refractive index (NRI) by using the hybridization effect of dish-net dimer metamaterials (MMs), in the GHz frequency regime. Two symmetric layers of dishnet structure are expected to realize a wideband of negative refractive index with a high transmitted power of 88%, a high figure of merit of 26 at 15.2 GHz and to make the MM insensitive for polarization/wide-incident angle of electromagnetic wave. By adjusting the distance between these layers and their dielectric thickness, the NRI bandwidth are flexibly controlled. Further study indicates that the refractive index strongly depends on tangent loss of the dielectric substrate and number of hybridized modes. Also, we numerically investigate the hybridization characteristic in various operational frequency ranges. The performance of the proposed metamaterial is numerically, theoretically and experimentally demonstrated. This paper strengthens the novelty and computation of NRI metamaterials.