Comment on “Dual-Band Perfect Metamaterial Absorber Based on an Asymmetric H-Shaped Structure for Terahertz Waves [Materials] (2018) [2193; https://doi.org/10.3390/ma11112193]”

In this paper, a flexible bianisotropic metasurface possessing omega-type coupling is presented. The designed metasurface behaves differently when excited from either forward (port 1) or back (port 2) sides. It provides an absorption of 99.46% at 15.1 Gigahertz (GHz), when illuminated from port 1, whereas, on simultaneous illumination from port 2, it behaves like a partially reflective surface (PRS). Furthermore, the presented metasurface not only acts as an in-band absorptive surface (port 1) and partially reflective surface (port 2), but it also provides 97% out-of-band transmission at 7.8 GHz. The response of the presented metasurface remains the same for both transverse Electric (TE) and transverse magnetic (TM) polarized wave or any arbitrary linearly polarized wave. Additionally, the response of the metasurface is angularly stable for any oblique incidence up to 45º. The proposed ultrathin flexible metasurface with absorption, partial reflection and out-of-band transmission properties can be used in the Fabry Perrot cavity antenna for gain enhancement with radar cross-section (RCS) reduction both for passband and stop-band filtering, and conformal antenna applications.

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“…The absorption of the proposed metasurface for port 1 can be found using the following mathematical relationship 37 , 38 : where …”

Section: Theoretical Analysis and Design Evolutionmentioning

confidence: 99%

A multifunctional ultrathin flexible bianisotropic metasurface with miniaturized cell size

Tamoor

Shoaib

Ahmed

et al. 2021

Sci Rep

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“…The decrease in the grain size also matters in the friction coefficient. In accordance with the Hall–Petch relation, grain size and hardness are inversely proportional to each other and as per Archard's wear law, hardness and wear rate are directly proportional to each other [35,36]. Table 3 indicates the CoF and wear rate of L-PBF and cast specimens.…”

Section: Resultsmentioning

confidence: 94%

“…In the steady wearing stage, both the surfaces are flat and the friction force was also uniform with less deviation [34]. Likewise, for wear rate, Figure 8 and as per Archard's wear law, hardness and wear rate are directly proportional to each other [35,36]. Table 3 indicates the CoF and wear rate of L-PBF and cast specimens.…”

Section: Friction and Wear Behaviourmentioning

confidence: 82%

Microstructural, mechanical and wear behaviour of Inconel-718 produced through laser-powder bed-fused additive manufacturing

Jeyaprakash

Yang

Ramkumar

2021

Materials Science and Technology

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The present work deals with the microstructure, nanoindentation and wear behaviour of Inconel-718 (IN-718) specimens fabricated through laser-powder bed fusion (L-PBF). To ensure the improvement in L-PBF, the results obtained were compared with the as-cast IN-718 specimen. Though IN-718 specimens exhibited precipitation and solid solution strengthening in both the fabrication techniques, L-PBF specimen has achieved better mechanical properties due to refinement of grains. The wear rate of cast and L-PBF IN-718 specimens were 0.98 and 0.27 mm3 m−1, respectively. Besides, the roughness average was reduced for L-PBF produced worn surface compared to as-cast specimen. In the light of the above observations, L-PBF can be a promising technique to fabricate IN-718 alloys for load carrying and wear applications.

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“…The absorption of an absorber can be characterized using the following equations: where and are absorption, reflection, and transmission, respectively 17 . For perfect absorption, both the transmitted and reflected components should be zero.…”

Section: Metasurface Designmentioning

confidence: 99%

Design and development of a multi-functional bi-anisotropic metasurface with ultra-wide out of band transmission

Ahmed

Tamoor

Hassan

et al. 2021

Sci Rep

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This paper presents a multi-functional bi-anisotropic metasurface having ultra-wide out of band transmission characteristics. The proposed metasurface is comprised of 90° rotated T-shaped configuration yielding greater than or equal to 50% out-of-band transmission from above L- to X-band. Moreover, this metasurface achieves a maximum of 99% out-of-band transmission at lower frequency bands (i.e., L-band). The simultaneous absorptive and controlled reflection functionalities are achieved at 15.028 to 15.164 GHz along with polarization-insensitive and angular stable properties. The proposed metasurface yields state-of-the-art features compared to already published papers and has broader scope for Fabry Perot cavity, Radar cross-section (RCS) reduction, electromagnetic compatibility and interference (EMC/I) shielding, selective multi-frequency bolometers, ultrathin wave trapping filters, sensors and beam-splitters in the microwave domain.

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Comment on “Dual-Band Perfect Metamaterial Absorber Based on an Asymmetric H-Shaped Structure for Terahertz Waves [Materials] (2018) [2193; https://doi.org/10.3390/ma11112193]”

Abstract: In a recent publication, Lu et al [...]

Cited by 17 publications

References 14 publications

A multifunctional ultrathin flexible bianisotropic metasurface with miniaturized cell size

A multifunctional ultrathin flexible bianisotropic metasurface with miniaturized cell size

Microstructural, mechanical and wear behaviour of Inconel-718 produced through laser-powder bed-fused additive manufacturing

Design and development of a multi-functional bi-anisotropic metasurface with ultra-wide out of band transmission

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