Design of a Graphene Based Terahertz Perfect Metamaterial Absorber With Multiple Sensing Performance

In this article, the graphene-based metamaterial perfect absorber was investigated in the terahertz region. Due to the geometrical symmetry of the proposed absorber structure, it is insensitive to changes in polarization and its angle, and the absorption value is almost the same over angles from 0 to 90 degrees. According to the configuration of the proposed structure, it is sensitive to changes in the refractive index. Placing graphene on top of the structure improves important sensing parameters, including sensitivity, due to good interaction with the analyte. The proposed structure is being investigated for medical applications including the diagnosis of malaria infection, cancer cells, and hemoglobin identification. The obtained results show the values of sensitivity, figure of merit, and quality coefficient as 2.63(THz/RIU), 175.3(1/RIU), and 523.35, respectively. The accuracy and correctness of the simulation results are checked using the method of equivalent circuit model and transfer matrix method, and there is good agreement between the simulation results and the mentioned methods.

I. Introduction

Graphene is a two-dimensional carbon allotrope that has received much attention due to its special properties and multi-purpose applications in the field of biosensors [1], [2]. Graphene has certain advantages that make it special compared to other materials. Firstly, the high electrical conductivity of graphene enables rapid detection of biomolecules, which leads to accurate and real-time monitoring of biological processes [3]. Secondly, due to the high density of graphene, the level of interaction with biomolecules increases, which leads to improved sensor sensitivity. Thirdly, it is possible to make strong and flexible biosensors due to their high mechanical strength and flexibility, making them suitable for use in biosensors [4], [5]. On the other hand, in the terahertz region, graphene is very popular due to its compatibility with biological molecules increased accuracy, and high sensitivity [6], [7]. The terahertz (THz) region has attracted considerable attention due to various applications including sensing, imaging, and communications [8], [9], [10].