A Dual-Band Terahertz Metamaterial Absorber Using an All-Metal Aluminum Hexagonal Metasurface Structure for Sensing of Cancerous Cells

This article proposes a dual-band terahertz metamaterial absorber (TMA) where all components of the designed structure are made of aluminum (optical) material. Unlike the metal-dielectric-metal structures typically found in the literature, the proposed structure has a lightweight material that does not contain a sandwich structure. Thus, the structure greatly simplifies the production process and reduces the cost. The results of electromagnetic and equivalent circuit simulations are compared based on the S₁₁ parameters (in dB), resulting in good agreement of findings by CST and ADS, respectively. The proposed TMA operates in dual frequency bands at 1.902 THz (f₁) and 1.976 THz (f₂), with strong absorption of 98.17% and 99.05%, respectively. The quality factors (Q-factors) corresponding to these resonant frequencies are 240.15, (f₁) and 181.61, (f₂). When the refractive index (RI) of the medium surrounding the TMA varies, the absorption peaks shift accordingly. The detection properties of the proposed TMA are examined as the RI of the surrounding medium is varied primarily between 1.34 and 1.39 with an increase of 0.01 for biomedical applications. The corresponding sensitivities of two resonance peaks are 0.794 THz/RIU and 0.971 THz/RIU, respectively. Since many samples, such as human blood, basal/breast/cervical cells, and cancerous cells, are found in this RI range, the proposed TMA sensor can be used as a viable biosensor in the identification of biological samples for real-world applications.