Highly tunable multi‐band <scp>THz</scp> absorber with circuit model representation using multi‐bias scheme

Aghaee, Toktam; Orouji, Ali A.

doi:10.1002/jnm.2777

Cited by 29 publications

(13 citation statements)

References 31 publications

(84 reference statements)

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“…According to the transmission line method, shown impedances in Figure 5 are presented by equations (5)–(8). It should be noted that Z 1 in equation (5) is calculable from Aghaee and Orouji (2020a, 2020b, 2020c). where:…”

Section: Structure and Transmission Line Methodsmentioning

confidence: 99%

A tunable broadband THz absorber using periodic arrays of graphene disks

Khani

Aghaee

Mazloum

et al. 2022

COMPEL

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Purpose A wide band perfect THz absorber is presented in this work. The structure includes two layers of graphene disks on the silicon dioxide dielectric layer while a golden plate is placed at the bottom to act as a fully reflecting mirror against THz waves. According to the simulations, the device is robust enough to show independent operation versus layers thicknesses variations, chemical potentials mismatches and changing of electron relaxation time. The designed THz absorber in this work is an appropriate basic block for several applications in THz optical systems such as sensors, detectors and modulators. Design/methodology/approach The layers in the proposed device are modeled via passive circuit elements and consequently, the equivalent circuit of the device is calculated. Leveraging the developed equivalent circuit model (ECM) and impedance matching concept, the proposed device is designed to perfect absorption with 4.7 THz bandwidth that possesses over 90% absorption. Ample simulations are performed using MATLAB (ECM) and CST (finite element method) to verify the superior performance of the device. According to the simulations, the device is robust enough to show independent operation versus layers thicknesses variations, chemical potentials mismatches and changing of electron relaxation time. Findings This work reports a wideband THz absorber, composed of two graphene layers. This paper considers the circuit model representation for two different layers of the device. For a unique structure, a highly tunable response versus chemical potential is obtained. The circuit model approach and impedance matching theory are exploited to reduce computational time regarding conventional approaches. Originality/value A wide band absorber in THz band is presented. Leveraging circuit model approach and impedance matching theory, the design procedure is simplified regarding CPU time and memory requirements compared to conventional methods. Detailed calculations and ample simulations verify the performance excellency of the device to absorb THz incident waves in 2–6.5 THz frequencies. Also, the robustness of the device is investigated versus parameters mismatches like layers thicknesses and chemical potentials values. According to the simulations and absorption response, the proposed device is an appropriate block to be used in THz optical systems such as detectors, imaging systems and optical modulators.

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Section: Structure and Transmission Line Methodsmentioning

confidence: 99%

A tunable broadband THz absorber using periodic arrays of graphene disks

Khani

Aghaee

Mazloum

et al. 2022

COMPEL

Self Cite

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“…According to [14], bias equalities can force patterns to experience different periods, and consequently, a degree of freedom is provided to adjust device reactions in desired frequencies. In addition, based on [12][13][14][15], [35][36][37], circuit representation of graphene patterns is reported with excellent accuracy compared to full numerical simulations. According to Fig.…”

Section: Proposed Devicementioning

confidence: 99%

A graphene-based THz wave duplexer and filter: Switching via gate biasing

Khani

2022

Optik

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This work introduces a Graphene-based multi-layer reconfigurable device as a wave duplexer in the THz frequency range. Adjusting transmitting and reflecting parts of incident waves alongside controlling absorption provides the interesting capability to select target waves in different frequencies. The proposed device includes periodic graphene patterns on both sides of silicon dioxide as substrate. Additionally, the patterns are biased differently compared to conventional patterns which makes it possible to achieve two distinct behaviors versus frequency. Exploiting equivalent circuit models (ECM) for graphene and dielectric, the whole device is modeled by passive RLC circuits.According to simulation results, the proposed device can transmit and reflect incident THz waves at desired frequencies in 0.1 THz to 30 THz which makes it an ideal candidate for manipulating THz waves in terms of transmission and reflection.

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“…The presented structure in this work is highly insensitive to polarity while benefits from wide angle absorption. Moreover, the developed equations to model graphene-based absorbers for graphene nano-disks are provided from [22] and [23].…”

Section: Introductionmentioning

confidence: 99%

Graphene-based THz absorber: adjustability via multiple gate biasing

Cyrus¹,

Biabanifard²

2021

Heliyon

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A multi-layer absorber using multi-bias arrays of graphene is proposed. The design methodology using the equivalent circuit model and matching concept is described. A heavy optimization process is performed to optimize bias values for different functionality. Leveraging, increased control parameters due to multi-bias scheme and simple circuit model representation, two operational modes are achieved as wide-band and multiband absorption. The proposed absorber can perfectly absorb THz incident waves between 5:2 THz À 6:3 THz in wide-band mode while shows perfect absorption response in 5:3 THz; 7:5 THz; 8 THz; 8:5 THz; 9 THz; and 9:5 THzin multi-band operational mode. Besides, response dependency to layers thicknesses, electron relaxation time, chemical potentials, and incident angle are reported to express acceptable sensitivity of the device. Such a reconfigurable absorber is in demand for several applications, ranging from medical imaging to indoor communication.

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

Cited by 29 publications

References 31 publications

A tunable broadband THz absorber using periodic arrays of graphene disks

A tunable broadband THz absorber using periodic arrays of graphene disks

A graphene-based THz wave duplexer and filter: Switching via gate biasing

Graphene-based THz absorber: adjustability via multiple gate biasing

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