Design of a multiband graphene-based absorber for terahertz applications using different geometric shapes

Abstract

By integrating multiple graphene-based geometric shapes, a unique absorber is proposed in this research, which achieves absorption peaks at 10 resonant frequencies, with an average absorption rate of 97.23% at terahertz frequency. The proposed structure consists of circular, triangular, square, pentagonal, and hexagonal ring-shaped absorbers to achieve multiband absorption. The proposed absorber is polarization-insensitive and has a wide incidence angle tolerance. Furthermore, increasing the graphene chemical potential value increases absorption while also tuning the resonance frequency. Additionally, this proposed configuration provides ultrawideband response at first band, with an absorption bandwidth percentage of 88.52. Two graphene-based absorbers are designed: one with geometric shapes that are in contact with one another and the other with geometric shapes that are not in contact with one another. Several investigations are exhibited on these two models to find the perfect combination of absorbers. The unique feature of this research is its novel, to the best of our knowledge, design and modeling, which provide absorption peaks at 10 resonant frequencies and also tuning of resonant frequency. All of these characteristics and findings distinguish the proposed multiband graphene-based absorber, which is well suited for terahertz applications.

Graphene-based ultra-wideband absorber for terahertz applications using hexagonal split ring resonators

“…The m c can be altered by providing a DC bias voltage to the graphene layer as shown in figure 1(e). An ion-gel layer with a permittivity of 1.852 and height of h g is placed over the graphene layer, allowing all of the periodically structured unit cells to be biased together [19,38,49,50]. In the fabrication process, Chemical vapor deposition (CVD) method can be used to grow two graphene layers, one of which is then transferred to the other side of the polyimide substrate.…”

“…The large size of these nanostructures, however, increases the system size due to the large variation in the band gap of the components, and manufacture of these nanostructures is a complex procedure [18]. Moreover, the performance of metal-based systems is limited by their poor electrical characteristics and temperature sensitivity over a wide frequency ranges [19][20][21][22]. Furthermore, due to the use of silver or gold at higher frequencies, metal-based devices are more expensive, and their lifetime is restricted due to oxidation and corrosion in metals [18].…”

VO2-Graphene Ultrathin Films: Enabling Wideband Switchable and Tunable THz Absorption

“…This phase transition behavior makes VO 2 -based absorbers highly versatile and suitable for a wide range of THz applications, including dynamic switching devices, adaptive camouflage systems, and temperature-sensitive sensors [13], [14], [15], [16]. Graphene-based absorbers also hold promise, with graphene's unique properties enabling efficient THz absorption and tunability [17], [18]. The fusion of graphene and VO2 offers unparalleled tunability, with dynamic adaptation enabled by VO 2 's phase transition and enhanced functionality, including durability, flexibility, and compatibility with emerging THz technologies.…”

A Compact Metamaterial Biosensor for Multi-Virus Detection With Tunability and High Incidence Angle Absorption

“…Additionally, metals are susceptible to degradation and rusting, rendering devices highly sensitive to temperature fluctuations and imposing constraints on their operational lifespan [17]. To address these challenges, some absorbers are designed using metal-free materials, such as graphene, which not only offers tuning capabilities but also mitigates these shortcomings [7], [18], [19]. Furthermore, certain dielectric-based absorbers are tailored for biosensing applications, and characterized by relatively greater thickness compared to typical metamaterial absorbers [12], [20]- [22].…”