Terahertz Electromagnetic (EM) Wave Absorber Based Biological Sensor for Cancer Detection Application

This work presents a terahertz metasurface absorber-based biomedical sensor for cancer cell detection applications. The proposed metasurface structure is designed using the metallic split annular ring on GaAs substrate, which offers more than 97% absorption at 3.77 THz with the FWHM absorption bandwidth and Q factor of 110 GHz and 34.27, respectively. The absorption mechanism inside the THEMWA is exploited with the help of a normalized input impedance $(\mathrm{Z}_{\text{eff}})$ plot and electric and magnetic coupling. Four-fold symmetry inside the resonator makes this structure's polarization insensitive. This study further uses this proposed structure as a sensor where cancer cells are detected by the shift of resonance frequency caused by variations (changes) in the refractive index of biological samples placed on top of the absorbers. The simulation's output demonstrates that the proposed structure's resonance frequency shifts from 3.608 THz to 3.59 THz with a change in refractive index from 1.35 to 1.40. This TEMWA-based sensor offered high sensitivity and FOM of 360 GHz/RIU and 3.273, respectively, which make this proposed structure a good candidate for refractive index-based biomedical sensors for cancer detection applications.