A Graphene Metasurface-Based Narrowband THz Biosensor for Non-Invasive Early Cancer Detection

Abstract

Terahertz spectral region, as a part of the electromagnetic spectrum, is an emerging field of technology for a future generation biomedical sensing applications thanks to the strong sensitivity to water, and its non-ionizing nature that guarantees safety for repeated uses on biological tissues. In this work, we propose a dual-band, tunable metasurface biosensor based on graphene that could be used for early in-vivo skin cancer detection. The sensor is designed to operate at two resonance frequencies: 1.092 THz and 3.18 THz. The double Debye framework was used to model optical properties of basal cell carcinoma (BCC). The sensor’s performance on the test sample showed a full width half maximum (FWHM) of 48 GHz and a resonance shift of 36 GHz. The sensitivity, figure of merit (FOM), detection limit and quality factor (Q) are found to be 0.2389 THz/RIU, 4.93 RIU-1 , and 21.7, 0.19 RIU respectively. Tunability of the sensor is obtained by varying graphene’s chemical potential or Fermi voltage from 0.8 to 1 eV. The design of biosensor was simulated in CST Microwave Studio, and its equivalent circuit model was developed. Thus, the numerically simulated results of the biosensor under sample testing confirm that the proposed design can be considered a label free promising candidate for THz biosensing applications.