Ultrathin High Q-Factor Perfect Metamaterial Absorber for Sensing Applications

This paper presents a simple ultrathin near-perfect metamaterial absorber with a high Q-factor in the microwave frequency range for refractive index sensing applications. The absorber is composed of an 8-point star ring with arrow extensions engraved over the grounded FR4 substrate. The designed absorber has an extended advantage of polarization stability and also has wide oblique incidence angle acceptance. The numerical simulation results reveal that the absorber has a narrow absorption band at the frequency of 4.62 GHz with an absorbance of 99.73%, and FWHM of 180 MHz. The Q-factor of this absorber is evaluated as 25.68 with average Sensitivity and average FoM of 0.47 GHz/RIU and 2.88, respectively. Herein, the absorbance of the designed absorber is also validated using the equivalent circuit modeling. The numerical analysis of the suggested absorber as a refractive index sensor shows enhanced parameters of sensitivity, linearity, and output variations, thus making this absorber a potential choice for various other sensor applications as well.