A Novel Design of Ultrathin Metasurface Structure for Terahertz Time-Domain Spectroscopy (THz-TDS) Applications

In this paper, an ultrathin metasurface structure is proposed for terahertz time-domain spectroscopy (THz-TDS) applications. The proposed structure consists of an inverted Tshaped strip surrounded by a rectangular-shaped split ring resonator (SRR) structure on a high-resistance silicon substrate. By inserting an inverted T-shaped strip inside the SRR, the coupling between the strip and SRR is improved and the sensitivity (refractive index unit (RIU)) of the proposed unit cell is increased. The proposed unit cell can provide an acceptable transmission characteristic around 0.6 THz. In addition, by using biological analyte, in this study brain Glioma, we are able to detect this material's concentrations by calculating the sensitivity in the range of 65 GHz/RIU. The proposed metasurface structure has small size and high sensitivity characteristics. Simulation results of the transmission coefficients and radiation characteristics show the effectiveness of the proposed design for biomedical applications.