scholarly journals A Tunable Terahertz Metamaterial Absorber Composed of Hourglass-Shaped Graphene Arrays

Nanomaterials ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 533 ◽  
Author(s):  
Yunping Qi ◽  
Yu Zhang ◽  
Chuqin Liu ◽  
Ting Zhang ◽  
Baohe Zhang ◽  
...  
Keyword(s):  
Fdtd Method ◽  
Bilayer Graphene ◽  
Metamaterial Absorber ◽  
Dual Band ◽  
Maximum Absorption ◽  
Monolayer Graphene ◽  
Selective Absorption ◽  
Chemical Potentials ◽  
Difference Time ◽  
Absorption Characteristics

In this paper, we demonstrate a tunable periodic hourglass-shaped graphene arrays absorber in the infrared (IR) and terahertz (THz) frequency bands. The effects of graphene geometric parameters, chemical potentials, periods, and incident angles on the pure absorption characteristics are studied by using the Finite Difference Time Domain (FDTD) method. In addition, this paper also analyzes the pure absorption characteristics of bilayer graphene arrays. The simulation results show that the maximum absorption reaches 38.2% for the monolayer graphene structure. Furthermore, comparing the bilayer graphene structure with the monolayer structure under the same conditions shows that the bilayer structure has a tunable dual-band selective absorption effect and has a higher maximum absorption of 41.7%. Moreover, it was found that there are dual-band tunable absorption peaks at 21.6   μ m and 36.3   μ m with the maximum absorption of 41.7% and 11%. The proposed structure is a convenient method which could be used in the design of graphene-based optoelectronic devices, biosensors, and environmental monitors.

scholarly journals Research on Perfect and Tunable Metamaterial Absorber Based on Crosshair-shaped Graphene

2021 ◽  
Vol 2109 (1) ◽  
pp. 012015
Author(s):  
Yiran Guo ◽  
Yunping Qi ◽  
Chuqin Liu ◽  
Weiming Liu ◽  
Xiangxian Wang
Keyword(s):  
Relaxation Time ◽  
Chemical Potential ◽  
Incident Angle ◽  
Fdtd Method ◽  
Reference Value ◽  
Metamaterial Absorber ◽  
Selective Absorption ◽  
Perfect Absorber ◽  
Wide Angle ◽  
Perfect Absorption

Abstract Graphene, as a new nano-material, according to the physical properties of electric field localization and selective absorption on light of surface plasmon resonance (SPR), a tunable, multi-band and wide-angle perfect absorber based on crosshair-shaped graphene is devised by using the Finite Difference in Time Domain (FDTD) method. In this paper, the effects of chemical potential, relaxation time, and incident angle of light on the absorptivity of graphene are systematically discussed. The simulation experiment shows that there are two absorption peaks with perfect absorption rate appeared in the study range, and the maximum modulation index can be obtained by changing the relaxation time. Finally, it proves that the absorber is insensitive to wide-angle of light. Thus, it is able to be concluded that the absorber has a great reference value to sensor, wireless communication, biomedical and other fields.

Tunable plasmonic filter based on graphene-layered waveguide

2018 ◽  
Vol 32 (08) ◽  
pp. 1850110 ◽  
Author(s):  
Yuncai Feng ◽  
Youwen Liu ◽  
Yaoyao Shi ◽  
Jinghua Teng
Keyword(s):  
Finite Difference Time Domain ◽  
Chemical Potential ◽  
Fdtd Method ◽  
Optical Filter ◽  
Monolayer Graphene ◽  
Physical Parameters ◽  
Plasmonic Filter ◽  
Tunable Optical Filter ◽  
Difference Time ◽  
Different Thickness

We propose a tunable band-stop plasmonic filter based on monolayer graphene with different thickness of structure, and the corresponding transmission characteristic is numerically investigated by using finite-difference time-domain (FDTD) method. The results show that the proposed filter can achieve a broad stopband that can be tuned by various physical parameters such as the chemical potential of graphene, the thickness of packing layers and so on. Our studies may be important for designing tunable optical filter, the fabrication of nano-integrated plasmonic circuits and the refractive index sensitive sensors.

scholarly journals A Dual Band Symmetric E-Shaped Split Ring Metamaterial Absorber for RF Energy Harvesting

2019 ◽  
Vol 8 (3) ◽  
pp. 3571-3574
Keyword(s):  
Energy Harvesting ◽  
Ring Resonator ◽  
Split Ring Resonator ◽  
Metamaterial Absorber ◽  
Dual Band ◽  
Maximum Absorption ◽  
Absorption Mechanism ◽  
Split Ring ◽  
Rf Energy Harvesting ◽  
Rf Energy

In this paper, a new metamaterial absorber which comprises of a symmetrically E shaped split ring resonator patches at the top of the FR4 substrate of height 1.6mm for RF Energy Harvesting is proposed. The proposed design provides two absorption peak one at 5.8GHz with a maximum absorption of about 99% and other at 7.8GHz with a maximum absorption of about 92%. The absorption mechanism is investigated for the proposed metamaterial absorber. Also the polarization behavior of the absorber is also analyzed under various angles of incidence. The absorber has been tuned in such a way to have good broadband response in the UWB range

scholarly journals Tunable Graphene-based Plasmonic Perfect Metamaterial Absorber in the THz Region

Micromachines ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 194 ◽  
Author(s):  
Zao Yi ◽  
Jiajia Chen ◽  
Chunlian Cen ◽  
Xifang Chen ◽  
Zigang Zhou ◽  
...  
Keyword(s):  
Transverse Electric ◽  
Incident Angle ◽  
Fdtd Method ◽  
Transverse Magnetic ◽  
Metamaterial Absorber ◽  
Terahertz Region ◽  
Surrounding Refractive Index ◽  
Perfect Metamaterial Absorber ◽  
The Impact ◽  
Difference Time

The optical performance of a periodically tunable plasma perfect metamaterial absorber based on a square-square-circle array we propose in the terahertz region is analyzed in this work by the finite difference time domain (FDTD) method. We not only discuss the impact of various parameters such as period a, length L, radius R, and incident angle θ under transverse magnetic (TM)- and transverse electric (TE)-polarization on the absorption spectra of the absorber but also study the effect of the Fermi energy EF and relaxation time τ. Finally, we simulate the spectra as the surrounding refractive index n changes to better evaluate the sensing performance of the structure, producing a sensitivity S of the structure of up to 15006 nm/RIU. On account of this research, we find that the absorber is beneficial to sensors and detectors in the terahertz region.

scholarly journals Design of a Wide Dual-Band Coplanar Probe Feed Antenna for WLANs Applications

2020 ◽  
Vol sceeer (3d) ◽  
pp. 13-16
Author(s):  
Nabil Abdulhussein ◽  
Abdulkareem Abdullah
Keyword(s):  
Finite Difference Time Domain ◽  
Fdtd Method ◽  
Three Dimensional ◽  
Dual Band ◽  
Operating Frequency ◽  
Center Frequency ◽  
Ieee 802.11B ◽  
Ieee 802.11A ◽  
Domain 3 ◽  
Difference Time

This paper presents a new design to obtain wide dual-band operation from a coplanar probe feed antenna loaded with two shorted walls. The lower band of proposed antenna has a 10 dB bandwidth of 611 MHz (24.18%) around the center frequency 2527MHz, and the upper band has a bandwidth of 1255 MHz (27.88%) around the center frequency 4501MHz. The obtained bandwidths cover WLANs operations on all bands. The bandwidth of the first operating frequency covers ISM band (2400-2483.5) MHz, which is required by IEEE 802.11b, g and Bluetooth standards, and the bandwidth of the second operating frequency covers U-NII1 (5150-5350) MHz band, which is required by IEEE 802.11a and HiperLAN2 standards, and also covers U-NII2 (5470-5725) MHz and U-NII3/ISM (5725-5825) MHz bands, which are required by IEEE 802.11a standard. A three dimensional finite-difference time-domain (3-D FDTD) method is employed to analyze the proposed structure and find its performance. The simulated results are compared with the experimental results.

Single-peak-regulation and wide-angle dual-band metamaterial absorber based on hollow-cross and solid-cross resonators

2020 ◽  
Vol 91 (3) ◽  
pp. 30901
Author(s):  
Yibo Tang ◽  
Longhui He ◽  
Jianming Xu ◽  
Hailang He ◽  
Yuhan Li ◽  
...  
Keyword(s):  
Transverse Electric ◽  
Surface Current ◽  
Dielectric Substrate ◽  
Transverse Magnetic ◽  
Metamaterial Absorber ◽  
Absorption Peak ◽  
Dual Band ◽  
Single Peak ◽  
Wide Angle ◽  
Surface Current Density

A dual-band microwave metamaterial absorber with single-peak regulation and wide-angle absorption has been proposed and illustrated. The designed metamaterial absorber is consisted of hollow-cross resonators, solid-cross resonators, dielectric substrate and metallic background plane. Strong absorption peak coefficients of 99.92% and 99.55% are achieved at 8.42 and 11.31 GHz, respectively, which is basically consistent with the experimental results. Surface current density and changing material properties are employed to illustrate the absorptive mechanism. More importantly, the proposed dual-band metamaterial absorber has the adjustable property of single absorption peak and could operate well at wide incidence angles for both transverse electric (TE) and transverse magnetic (TM) waves. Research results could provide and enrich instructive guidances for realizing a single-peak-regulation and wide-angle dual-band metamaterial absorber.

scholarly journals Designing the Hotspots Distribution by Anisotropic Growth

Molecules ◽  
2021 ◽  
Vol 26 (1) ◽  
pp. 187
Author(s):  
Tianshun Li ◽  
Renxian Gao ◽  
Xiaolong Zhang ◽  
Yongjun Zhang
Keyword(s):  
Au Nanoparticles ◽  
Fdtd Method ◽  
Polarization Dependence ◽  
Noble Metal Nanoparticles ◽  
Oblique Angle Deposition ◽  
Matlab Simulation ◽  
Different Shapes ◽  
Plasma Enhancement ◽  
Difference Time ◽  
Good Agreement

Changing the morphology of noble metal nanoparticles and polarization dependence of nanoparticles with different morphologies is an important part of further research on surface plasma enhancement. Therefore, we used the method based on Matlab simulation to provide a simple and effective method for preparing the morphologies of Au nanoparticles with different morphologies, and prepared the structure of Au nanoparticles with good uniformity and different morphologies by oblique angle deposition (OAD) technology. The change of the surface morphology of nanoparticles from spherical to square to diamond can be effectively controlled by changing the deposition angle. The finite difference time domain (FDTD) method was used to simulate the electromagnetic fields of Au nanoparticles with different morphologies to explore the polarization dependence of nanoparticles with different shapes, which was in good agreement with Raman spectrum.

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