Highly sensitive circle enclosed D-pad resonator-based narrowband Metamaterial Absorber for biosensing applications

Abstract

This paper presents the development of an ultra-thin metamaterial-based absorber, meticulously engineered to exhibit nearperfect narrow-band absorption characteristics, specifically for sensing within the C band. The absorber consists of a copper ground, copper resonator, and Rogers RO4350B substrate, which incorporates a sophisticated metallic structure configured as a D-pad absorber. The overall size of the unit cell structure is 10x10 mm². Through rigorous simulations and empirical measurements, the absorber achieves a highly concentrated absorption peak at 6.6 GHz, attaining a peak absorbance efficiency of 99.99%, with a full width at half maximum (FWHM) bandwidth of 260 MHz. The quality factor of the proposed sensor is analytically determined to be 253.85, with the sensitivity quantified at 1.47 GHz/RIU, and the figure of merit is calculated to be 38.8. Furthermore, this D-pad metamaterial absorber can be adapted for detecting various proteins, leveraging its high sensitivity and specificity. Through the absorber’s surface functionalization with specific binding agents, it is capable of identifying and quantifying different proteins, making it a versatile tool for applications in medical diagnostics, environmental monitoring, and food safety. This multifunctional capability highlights the absorber’s potential as a highly effective sensor in diverse scientific and industrial domains.