A MoS2-based broadband and multiband metamaterial absorber in the visible band

2020 ◽  
Vol 34 (34) ◽  
pp. 2050397
Author(s):  
Shitong Song ◽  
Fanyi Liu ◽  
Limei Qi ◽  
Zhao Zhang ◽  
Haodong Wang ◽  
...  
Keyword(s):  
Physical Mechanism ◽  
Impedance Matching ◽  
Dielectric Substrate ◽  
Metamaterial Absorber ◽  
Matching Theory ◽  
Broadband Absorber ◽  
Broadband Absorption ◽  
Visible Band ◽  
Relative Bandwidth ◽  
New Perspective

A broadband MoS2-based absorber composed of Ag rod/MoS2/dielectric/Ag is proposed in the visible band. The relative bandwidth is 65% for the absorption above 80%. The absorber also has the properties of polarization-independence and wide-angle absorption. Impedance matching theory is used to analyze the physical mechanism of the broadband absorption. By investigating the absorption property of each part of the absorber, it is found that the absorption is enhanced by introducing the two-dimensional material MoS2. The broadband absorber can be changed to be multiband absorber by changing the thickness of dielectric substrate. This structure provides a new perspective to enhance absorption in the visible band and has promising applications in solar cells.

A simple two-layer broadband metamaterial absorber for solar cells

2021 ◽  
pp. 2150291
Author(s):  
Fanyi Liu ◽  
Limei Qi
Keyword(s):  
Solar Cells ◽  
Precious Metal ◽  
Simple Structure ◽  
Impedance Matching ◽  
Cost Effective ◽  
Metamaterial Absorber ◽  
Matching Theory ◽  
Broadband Absorber ◽  
Broadband Absorption ◽  
Silicon Rods

A broadband absorber composed of silicon rods and nickel ground is proposed in the visible band. The absorption above 98% can be obtained in the frequency range of [Formula: see text] THz with strong polarization independence and angle independence. The impedance matching theory and field distributions of eigenmodes are used to analyze the physical mechanism of the broadband absorption. The absorber has a simple structure with only two layers, which is composed of silicon and nickel. Nickel is a non-precious metal, which is cheaper than the precious metal materials commonly used in metamaterial absorber. The proposed cost-effective absorber with simple structure has great potential in the application of solar cells.

A SIW Horn Antenna without Broad Wall Loaded with Trapezoidal Air Slot

2020 ◽  
Vol 35 (9) ◽  
pp. 1047-1052
Author(s):  
Mingxi Zhang ◽  
Wei Li ◽  
Shaobin Liu ◽  
Xiaochun Liu ◽  
Chen Wu ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Surface Waves ◽  
Free Space ◽  
Impedance Matching ◽  
Horn Antenna ◽  
Dielectric Substrate ◽  
Actual Measurement ◽  
Relative Bandwidth ◽  
Measurement Results ◽  
Wide Wall

In this paper, a SIW horn antenna without broad wall loaded with trapezoidal air slot is proposed, processed, and tested. Based on the SIW horn antenna, this antenna strips off the wide wall at the horn diameter, introduces surface waves on the surface of the dielectric substrate, and improves the impedance matching between the antenna and free space. Further, trapezoidal air slots are loaded on the exposed dielectric substrate, gradually changes the dielectric constant of the dielectric substrate, so that the dielectric constant of the dielectric substrate can get closer to which of air, and the working bandwidth can be further expanded. The actual measurement results show that the working bandwidth of the antenna is 15.2-38GHz, the relative bandwidth reaches to 85.7%, and the maximum gain in the band is 9.1dBi.

scholarly journals A Broadband Tunable Terahertz Metamaterial Absorber Based on Single-Layer Complementary Gammadion-Shaped Graphene

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 860 ◽  
Author(s):  
Fu Chen ◽  
Yongzhi Cheng ◽  
Hui Luo
Keyword(s):  
Energy Level ◽  
Graphene Sheet ◽  
Fermi Energy ◽  
Single Layer ◽  
Dielectric Substrate ◽  
Transverse Magnetic ◽  
Metamaterial Absorber ◽  
Absorption Capacity ◽  
Fermi Energy Level ◽  
Broadband Absorption

We present a simple design of a broadband tunable metamaterial absorber (MMA) in the terahertz (THz) region, which consists of a single layer complementary gammadion-shaped (CGS) graphene sheet and a polydimethylsiloxane (PDMS) dielectric substrate placed on a continuous metal film. The Fermi energy level (Ef) of the graphene can be modulated dynamically by the applied DC bias voltage, which enables us to electrically control the absorption performance of the proposed MMA flexibly. When Ef = 0.8 eV, the relative bandwidth of the proposed MMA, which represents the frequency region of absorption beyond 90%, can reaches its maximal value of 72.1%. Simulated electric field distributions reveal that the broadband absorption mainly originates from the excitation of surface plasmon polaritons (SPPs) on the CGS graphene sheet. Furthermore, the proposed MMA is polarization-insensitive and has wide angles for both transverse-electric (TE) and transverse-magnetic (TM) waves in the broadband frequency range. The broadband absorption capacity of the designed MMA can be effectively adjusted by varying the Fermi energy level of graphene. Lastly, the absorbance of the MMA can be adjusted from 42% to 99.1% by changing the Ef from 0 eV to 0.8 eV, which is in agreement with the theoretical calculation by using the interference 41theory. Due to its simple structure and flexible tunability, the proposed MMA has potential application prospects in tunable filtering, modulators, sensing, and other multispectral devices.

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.

Tuning the impedance matching of microsphere Co for strong broadband absorption

2021 ◽  
Vol 528 ◽  
pp. 167720
Author(s):  
Jing Zhang ◽  
Yuchang Su ◽  
Qiushan Yu ◽  
Zhongbao Luo ◽  
Hongzhi Zhang
Keyword(s):  
Impedance Matching ◽  
Broadband Absorption

Realizing high-efficiency low frequency sound absorption of underwater meta-structures by acoustic siphon effect

2021 ◽  
pp. 2150319
Author(s):  
Li Bo Wang ◽  
Cheng Zhi Ma ◽  
Jiu Hui Wu ◽  
Chong Rui Liu
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
High Efficiency ◽  
Physical Mechanism ◽  
Low Frequency ◽  
Area Ratio ◽  
Underwater Acoustic ◽  
Element Simulation ◽  
Average Absorption Coefficient ◽  
New Perspective

The underwater acoustic siphon effect is proposed in this work, which aims to reveal the basic physical mechanism of high-efficiency sound absorption in meta-structures composed of multiple detuned units. Furthermore, the influence of the area ratio on the underwater acoustic siphon effect is then investigated by finite element simulation (FES) and theoretical calculation. On this basis, a meta-structure with the maximum absorption coefficient of almost 100% and average absorption coefficient of 80% at 600–1400 Hz is achieved. The underwater acoustic siphon effect could provide a better understanding of high-efficiency sound absorption and offer a new perspective in controlling underwater noises.

Impedance Matching between Signal Generator and Piezoelectric Transducer

2012 ◽  
Vol 472-475 ◽  
pp. 1488-1491
Author(s):  
Zhen Jiang Tan ◽  
Ming Zhou
Keyword(s):  
High Power ◽  
Piezoelectric Transducer ◽  
Perfect Matching ◽  
Impedance Matching ◽  
Signal Generator ◽  
Matching Theory ◽  
Signal Source ◽  
Key Technology ◽  
Power Pulse ◽  
High Power Pulse

In order to acquire enough energy, high power pulse must be used to drive a piezoelectric transducer. At the same time, it is a key technology to design an impedance matching circuit between a signal generator and a piezoelectric transducer so that signal source can transmit energy to the piezoelectric transducer effectively. In the paper, the impedance matching theory is analyzed. And, a method of using an oscilloscope to measure resonance frequency of the piezoelectric transducer is tested, through which, a perfect matching circuit is designed.

scholarly journals An Ultra-Wideband THz/IR Metamaterial Absorber Based on Doped Silicon

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2590 ◽  
Author(s):  
Huafeng Liu ◽  
Kai Luo ◽  
Shihao Tang ◽  
Danhua Peng ◽  
Fangjing Hu ◽  
...  
Keyword(s):  
Incident Angle ◽  
Average Power ◽  
Far Infrared ◽  
Metamaterial Absorber ◽  
Ultra Wideband ◽  
Broadband Absorption ◽  
Wide Range ◽  
Doped Silicon ◽  
Simulated Field ◽  
Underlying Mechanisms

Metamaterial-based absorbers have been extensively investigated in the terahertz (THz) range with ever increasing performances. In this paper, we propose an all-dielectric THz absorber based on doped silicon. The unit cell consists of a silicon cross resonator with an internal cross-shaped air cavity. Numerical results suggest that the proposed absorber can operate from THz to far-infrared regimes, having an average power absorption of ∼95% between 0.6 and 10 THz. Experimental results using THz time-domain spectroscopy show a good agreement with simulations. The underlying mechanisms for broadband absorption are attributed to the combined effects of multiple cavities modes formed by silicon resonators and bulk absorption in the doped silicon substrate, as confirmed by simulated field patterns and calculated diffraction efficiency. This ultra-wideband absorption is polarization insensitive and can operate across a wide range of the incident angle. The proposed absorber can be readily integrated into silicon-based photonic platforms and used for sensing, imaging, energy harvesting and wireless communications applications in the THz/IR range.

scholarly journals Planar Dual Polarized Metasurface Array for Microwave Energy Harvesting

Electronics ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1985
Author(s):  
Maged A. Aldhaeebi ◽  
Thamer S. Almoneef
Keyword(s):  
Energy Harvesting ◽  
Dielectric Substrate ◽  
Metamaterial Absorber ◽  
Absorption Efficiency ◽  
Unit Cell ◽  
Resistive Load ◽  
Electromagnetic Energy Harvesting ◽  
Absorbed Power ◽  
Simulation Results ◽  
Dual Polarized

The design of a dual polarized metasurface collector based on the metamaterial full absorption concept for electromagnetic energy harvesting is introduced. Unlike previous metamaterial absorber designs, here the power absorbed is mostly dissipated across a resistive load rather than within the dielectric substrate. This is achieved by channeling the absorbed power to an optimal resistive load through a via hole. The simulation results show that a power absorption efficiency of 98% is achieved at an operating frequency of 2 GHz for a single unit cell. A super unit cell consisting of four cells with alternating vias was also designed to produce a dual polarized metasurface. The simulation results yielded a radiation to AC efficiency of around 98% for each polarization.

Sign in / Sign up

Export Citation Format

Share Document