Ultra-wideband terahertz graphene absorber using circuit model

Biabanifard, Mohammad; Abrishamian, Mohammad Sadegh

doi:10.1007/s00339-018-2248-3

Cited by 38 publications

(26 citation statements)

References 38 publications

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“…[6][7][8][9][10][11][12] However, the requirement of some applications is tunable narrowband THz absorbers, 13 while the requirement of the others is ultra-broadband absorbers, 14,15 and research in this area is ongoing. [16][17][18] Various geometrical structures including circular patches, 19 ring arrays, 20 graphene stacks, 21,22 rectangular fish-scale, 23 cascade metal-dielectric pairs, 24 and specific ring resonator 25 have been proposed to achieve ultra-wideband or broadband absorption. However, with all the works that have been down, providing a simple design approach to increase bandwidth along with fabrication issues is still challenging.…”

Section: Introductionmentioning

confidence: 99%

“…In application point of view, THz metamaterial absorbers, the artificial sub‐wavelength composite materials, play a key role in various types of devices, and the THz spectra have the potential of realizing these devices; some of the branches of these applications are indoor communications, sensing, biosensing, filtering, imaging, and medical applications . However, the requirement of some applications is tunable narrowband THz absorbers, while the requirement of the others is ultra‐broadband absorbers, and research in this area is ongoing . Various geometrical structures including circular patches, ring arrays, graphene stacks, rectangular fish‐scale, cascade metal‐dielectric pairs, and specific ring resonator have been proposed to achieve ultra‐wideband or broadband absorption.…”

Section: Introductionmentioning

confidence: 99%

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Circuit modeling of ultra‐broadband terahertz absorber based on graphene array periodic disks

Aghaee

Orouji

2019

Int J Numerical Modelling

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The realization of broadband absorption in the terahertz spectra is of significant interest in advanced terahertz applications. In this work, a novel ultrabroadband absorber based on the periodic array of graphene disks and graphene continues sheet is proposed. A developed transmission line theory besides the analytical circuit model of graphene disks and graphene continues sheet are exploited to describe the absorber structure by its circuit model. By using three graphene layers and considering impedance matching concept, the normalized bandwidth of 90% absorption is extended up to 121% of the central frequency. Also, the dependence of the absorption spectra on the structure parameters is investigated and analyzed. Moreover, the performance of the device under possible fabrication errors is discussed. In pursuit of evaluating the efficiency, accuracy, and validity of the proposed method, full-wave numerical modeling is performed by the finite element method. The results show that the proposed circuit approach, in addition to having advantages in terms of computing time and the need for memory resource, is in a good agreement with the full-wave simulations. Furthermore, the structure of the absorber is relatively simple, and it can be manufactured by chemical vapor deposition techniques.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Circuit modeling of ultra‐broadband terahertz absorber based on graphene array periodic disks

Aghaee

Orouji

2019

Int J Numerical Modelling

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“…In this article, a temperature of T = 300 K (room temperature) and τ = 0.5 ps are assumed. [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] Here in this work, a modified circuit model approach is used to describe layers exploiting developed circuit representation in Reference 26. According to References 26-30, periodic arrays of Nano-disks can be modeled via passive circuit elements while physical features and technology dependents parameters are embedded in-circuit elements.…”

Section: Proposed Configurationmentioning

confidence: 99%

“…So, the surface conductivity of graphene (with the assumption of exp[ jωt ] as the time‐harmonic dependency) can be written as:

σ_{g} ((),,,, ω, μ_{c}, τ, T) = - j \frac{e^{2} k_{B} T}{π h^{2} ((), ω - j τ^{- 1})} \times ([], \frac{μ_{c}}{k_{B} T} + 2 \ln ([], \exp ((), - \frac{μ_{c}}{k_{B} T}) + 1))

where e is the electron charge, k B is the Boltzmann constant, ℏ is the reduced Planck constant, τ is the relaxation time of electrons, μ c is the chemical potential, and T is the temperature. In this article, a temperature of T = 300 K (room temperature) and τ = 0.5 ps are assumed 11‐25 …”

Section: Proposed Configurationmentioning

confidence: 99%

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Highly tunable multi‐band THz absorber with circuit model representation using multi‐bias scheme

Aghaee

Orouji

2020

Int J Numerical Modelling

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Utilizing a double bias scheme for graphene patterns as a single layer, a THz meta-surface structure is proposed. The structure includes two dual bias layers and a graphene continuous sheet on top. So five possible biases are available which lead to a highly tunable absorption response. All consisting parts are modeled via passive circuit elements to obtain whole device input impedance. Then impedance matching theory is used to investigate potential frequencies for perfect absorption. Also, ample simulations are performed to show the validity and accuracy of theoretical descriptions. According to the simulation results in the conventional finite element method as a reference approach is in acceptable agreement with the developed circuit model approach. The proposed structure shows nearly perfect absorption in 5, 6, 7, and 8 THz with absorption rate over 90%. Such a tunable reaction is in incredible requests in optical systems and has various applications in structuring sensors, modulators, and photonic functions.

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Ultra‐Wideband Integrated Graphene‐Based Absorbers for Terahertz Waveguide Systems

Campion

Xenidis

Smirnov

et al. 2022

Adv Elect Materials

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This article presents novel graphene‐based absorber materials which can be directly integrated in terahertz waveguide systems. A simple, low‐cost integration method is developed, allowing graphene augmented inorganic nanofibers to be embedded inside a metallic waveguide. In contrast to existing absorbers, the ability to embed such materials in a metallic waveguide allows them to be integrated into complete terahertz systems for large‐scale applications. The electromagnetic properties of such materials are then examined using standard network analysis techniques. A wideband measurement setup is developed to enable measurement of a single sample from 67 to 500 GHz, eliminating the need to fabricate multiple samples. The porosity of the integrated material leads to excellent electromagnetic performance across a wide range of frequencies. The samples are found to have a reflection coefficient less than −10 dB for frequencies above 200 GHz, while their attenuation per unit length exceeds 35 dB mm−1. The low reflectivity of the material allows it to be used in systems applications where undesired reflections must be avoided. The electromagnetic shielding effectiveness of the material is assessed, with a total effectiveness of 20–45 dB observed for 0.84 mm thick samples.

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Ultra-wideband terahertz graphene absorber using circuit model

Cited by 38 publications

References 38 publications

Circuit modeling of ultra‐broadband terahertz absorber based on graphene array periodic disks

Circuit modeling of ultra‐broadband terahertz absorber based on graphene array periodic disks

Highly tunable multi‐band THz absorber with circuit model representation using multi‐bias scheme

Ultra‐Wideband Integrated Graphene‐Based Absorbers for Terahertz Waveguide Systems

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