scholarly journals Tunable multi-band terahertz absorber using a single-layer square graphene ring structure with T-shaped graphene strips

2020 ◽  
Vol 28 (8) ◽  
pp. 11482 ◽  
Author(s):  
Kai-Da Xu ◽  
Jianxing Li ◽  
Anxue Zhang ◽  
Qiang Chen
Keyword(s):  
Single Layer ◽  
Ring Structure ◽  
Terahertz Absorber ◽  
Multi Band

Polarization sensitive tunable multi-band terahertz absorber based on single-layered graphene rings

2021 ◽  
Author(s):  
PENG CHEN ◽  
Mingjun Tang ◽  
AIYUN LIU ◽  
Yishan Hu ◽  
Ling Li ◽  
...  
Keyword(s):  
Terahertz Absorber ◽  
Multi Band

scholarly journals Numerical Study of an Ultra-Broadband All-Silicon Terahertz Absorber

2020 ◽  
Vol 10 (2) ◽  
pp. 436 ◽  
Author(s):  
Jinfeng Wang ◽  
Tingting Lang ◽  
Tingting Shen ◽  
Changyu Shen ◽  
Zhi Hong ◽  
...  
Keyword(s):  
Numerical Study ◽  
Structural Parameters ◽  
Impedance Matching ◽  
Single Layer ◽  
Transverse Magnetic ◽  
Absorption Efficiency ◽  
Absorption Mechanism ◽  
Loss Mechanism ◽  
Perfect Absorption ◽  
Terahertz Absorber

In this article we present and numerically investigate a broadband all-silicon terahertz (THz) absorber which consists of a single-layer periodic array of a diamond metamaterial layer placed on a silicon substrate. We simulated the absorption spectra of the absorber under different structural parameters using the commercial software Lumerical FDTD solutions, and analyzed the absorption mechanism from the distribution of the electromagnetic fields. Finally, the absorption for both transverse electric (TE) and transverse magnetic (TM) polarizations under different incident angles from 0 to 70° were investigated. Herein, electric and magnetic resonances are proposed that result in perfect broadband absorption. When the absorber meets the impedance matching principle in accordance with the loss mechanism, it can achieve a nearly perfect absorption response. The diamond absorber exhibits an absorption of ~100% at 1 THz and achieves an absorption efficiency >90% within a bandwidth of 1.3 THz. In addition, owing to the highly structural symmetry, the absorber has a polarization-independent characteristic. Compared with previous metal–dielectric–metal sandwiched absorbers, the all-silicon metamaterial absorbers can avoid the disadvantages of high ohmic losses, low melting points, and high thermal conductivity of the metal, which ensure a promising future for optical applications, including sensors, modulators, and photoelectric detection devices.

Numerical Study on Controllable Multi-Band Microwave Metamaterial Absorbers

2011 ◽  
Vol 239-242 ◽  
pp. 1260-1264
Author(s):  
Wei Wei Ji ◽  
Tao Wang ◽  
Yan Nie ◽  
Rong Zhou Gong
Keyword(s):  
Numerical Study ◽  
Impedance Matching ◽  
Single Layer ◽  
Surface Current ◽  
Metamaterial Absorber ◽  
Band Absorption ◽  
Different Dimensions ◽  
Resonant Feature ◽  
Difference Time ◽  
Multi Band

Based on the impedance matching and electromagnetic resonant characteristic of composite materials, we present a single-layer metamaterial absorber consisting of arch copper loop and substrate FR-4, of which the resonant frequency depended on the loop’s geometry perimeter. By combining resonant loops with different dimensions together, we can achieve multi-band absorption. The standard finite difference time domain method was used to calculate the magnitudes of reflectance, and then the induced surface current and power loss distributions were demonstrated to analyze the insight physical picture of the multi-band resonant feature. By optimizing the simulation results, the absorptivities of two absorption peaks are all above 98% when the number of copper loops is two, 95% for three absorption peaks of three loops, and 87% for four absorption peaks of four loops.

POLARIZATION-INDEPENDENT METAMATERIAL ABSORBER FOR SINGLE BAND AND MULTI-BAND FREQUENCY

2015 ◽  
Vol 77 (10) ◽  
Author(s):  
Osman Ayop ◽  
Mohamad Kamal A. Rahim ◽  
Noor Asniza Murad
Keyword(s):  
Ring Structure ◽  
Circular Ring ◽  
Unit Cell ◽  
Single Band ◽  
Frequency Separation ◽  
Dual Band ◽  
Band Frequency ◽  
Ring Shape ◽  
Polarization Independent ◽  
Multi Band

This paper presents the design and simulation of polarization-independent type of metamaterial absorbers (MMAbs) at X-band frequency. The advantage of polarization-independent MMAbs is it can absorbs incident electromagnetic (EM) wave in all polarization states. It can be achieved by applying circular ring shape in a unit cell of MMAbs because the shape is very symmetry. The simulation is done in a unit cell for each proposed MMAbs structures. The FR4 substrate is used for MMAbs structure designs. The designed MMAbs structures can be divided into two parts which is circular ring and modified circular ring. The characteristics of both structure are studied through simulation process using CST software. Parametric study is conducted to observe the effect of each parameters in unit cell on the absorbing magnitude and frequency. It is observed that circular ring structures can achieve high EM wave  absorbance for single band and multi band frequency. Since frequency separation distant limitation occurred, the modified circular ring structure is proposed by adding copper lines on the original circular ring structure. Thus, dual band frequency with close separation distant between two resonant frequencies is obtained as close as 1 GHz compared to the original dual band circular ring which is 2 GHz.

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