Graphene disks for frequency control of terahertz waves in broadband applications
- PDF / 2,414,926 Bytes
- 14 Pages / 595.276 x 790.866 pts Page_size
- 64 Downloads / 210 Views
Graphene disks for frequency control of terahertz waves in broadband applications Sahar Borzooei1 · Ehsan Rezagholizadeh2 · Mohammad Biabanifard2
© Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract The terahertz (THz) gap lying between the microwave and optical parts of the electromagnetic spectrum has attracted immense attention due to its applications between radiofrequency (RF)/microwave and photonic systems. A structure consisting of a graphene sheet sandwiched between two graphene disks is introduced herein to control the reflection, absorption, and transmission of THz waves. The proposed metamaterial structures are designed analytically using transmission line theory. Also, the dimensions of the structure and the electrical gating of the graphene are optimized utilizing a genetic algorithm. The structure is simulated using two different methods: (1) a circuit model based on transmission line theory and (2) commercial full-wave software based on the finite element method, which are verified by the agreement between their results. Finally, the proposed method is used to design a THz filter and THz wave absorber, which are in great demand for application in modulators, sensors, detectors, and imaging systems. Keywords Absorber design · Impedance matching · Graphene · Circuit method · Resonator · Genetic algorithm · Coupling effect
1 Introduction Engineering has achieved cutting-edge solutions through salient advancements in nanotechnology, leading to appropriate methods for the fabrication of electronic devices for particular applications. Such procedures can dramatically enhance sustainability and energy efficiency by improving the productivity and quality of manufacturing processes. In recent years, metamaterial structures have been subject to increasing study due to their undeniable role in a varied range of applications. These artificial subwavelength composite materials play a significant role in numerous basic structures and devices that are utilized in imaging, biosensing, communications, and medical applications [1–5]. Due to its photonic and optoelectronic properties, graphene has attracted a great deal of attention for use in devices at THz frequencies (roughly from 0.1 to 10 THz) * Sahar Borzooei [email protected] 1
Department of Electrical and Electronics Engineering, Malek Ashtar University of Technology, Tehran, Iran
Department of Electrical Engineering, K. N. Toosi University of Technology, Tehran, Iran
2
[2, 3, 6–9]. Moreover, it has been illustrated that graphene, a two-dimensional one-atom-thick densely packed sheet in which atoms form a honeycomb lattice, outperforms silicon materials, being one of the preferred materials for the design of basic building blocks such as wave absorbers and filters due to its capability to support plasmon polariton-based absorption at THz frequencies [8, 10]. Furthermore, in the mentioned region of the spectrum, due to its zero bandgap, this material benefits from lower losses compared with noble metals such as gold
Data Loading...
