Optically transparent terahertz triple-band and dual-band metamaterial absorber

Circuit World ◽  
2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Elakkiya A. ◽  
Radha Sankararajan ◽  
Sreeja B.S.
Keyword(s):  
Planar Structure ◽  
Dual Band ◽  
Content Type ◽  
Unit Cells ◽  
Band Absorption ◽  
Multiple Unit ◽  
Large Unit Cell ◽  
The One ◽  
High Absorption ◽  
Triple Band

Purpose The proposed metamaterial absorber (MMA) has the following advantages: first, the structure of the MMA consists of one planar metallic resonator, which presents a new design approach to obtain a multiband absorption response, rather than using multiple unit-cells in the one large unit cell or stacking different layers. Second, the simultaneous realization of triple-band and dual-band absorption (or bi-functional absorption) at five different frequencies can integrate the respective advantages of the triple functions of the triple-band MMA and double-band MMA, and therefore, the bi-functional MMA will find more application prospects than multiple-functional devices of triple-band and dual-band. Third, the authors simulated the three combinations of MMA here, which is indium tin oxide (ITO)-Polyimide-ITO, ITO-Teflon-ITO and ITO-polyethylene terephthalate (PET)-ITO for the same planar structure and achieve a high absorption rate. Finally, the proposed structure is polarization and angle independent in nature. Design/methodology/approach This absorption device consists of the top circular resonator, the middle insulating SiO2 medium layer and the bottom metallic copper ground plane placed on a substrate. The conductivity of the copper metal is s = 5.8 × 107 s/m. As the transmission of the MMA structure is zero, the substrate materials can be selected randomly. Totally four combinations of terahertz MMA are designed and simulated here which are ITO- SiO2 –ITO, ITO-Polyimide-ITO, ITO-Teflon-ITO and ITO- PET-ITO for the same planar structure. Findings Compared with previous MMAs, the proposed MMA has the following advantages: First, the structure of the MMA consists of one planar metallic resonator, which presents a new design approach to obtain a multiband absorption response, rather than using multiple unit-cells in the one large unit cell or stacking different layers. Second, the simultaneous realization of triple-band and dual-band absorption (or bi-functional absorption) at five different frequencies can integrate the respective advantages of the triple functions of the triple-band MMA and double-band MMA, and therefore, the bi-functional MMA will find more application prospects than multiple-functional devices of triple-band and dual-band. Third, the authors simulated the three combinations of MMA here, which is ITO-polyimide-ITO, ITO-Teflon-ITO and ITO- PET-ITO for the same planar structure and achieve a high absorption rate. Finally, the proposed structure is polarization and angle independent in nature. Originality/value First, the structure of the MMA consists of one planar metallic resonator, which presents a new design approach to obtain a multiband absorption response, rather than using multiple unit-cells in the one large unit cell or stacking different layers. Second, the simultaneous realization of triple-band and dual-band absorption (or bi-functional absorption) at five different frequencies can integrate the respective advantages of the triple functions of the triple-band MMA and double-band MMA, and therefore, the bi-functional MMA will find more application prospects than multiple-functional devices of triple-band and dual-band. Third, the authors simulated the three combinations of MMA here, which is ITO-polyimide-ITO, ITO-Teflon-ITO and ITO-PET-ITO for the same planar structure and achieve a high absorption rate. Finally, the proposed structure is polarization and angle independent in nature.

scholarly journals Design and Fabrication of a Triple-Band Terahertz Metamaterial Absorber

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1110
Author(s):  
Jinfeng Wang ◽  
Tingting Lang ◽  
Zhi Hong ◽  
Meiyu Xiao ◽  
Jing Yu
Keyword(s):  
Optical Communication ◽  
Transverse Magnetic ◽  
Metamaterial Absorber ◽  
Absorption Mechanism ◽  
Symmetric Configuration ◽  
Electric And Magnetic Fields ◽  
Polarization Insensitive ◽  
Band Absorption ◽  
High Absorption ◽  
Triple Band

We presented and manufactured a triple-band terahertz (THz) metamaterial absorber with three concentric square ring metallic resonators, a polyethylene terephthalate (PET) layer, and a metallic substrate. The simulation results demonstrate that the absorptivity of 99.5%, 86.4%, and 98.4% can be achieved at resonant frequency of 0.337, 0.496, and 0.718 THz, respectively. The experimental results show three distinct absorption peaks at 0.366, 0.512, and 0.751 THz, which is mostly agreement with the simulation. We analyzed the absorption mechanism from the distribution of electric and magnetic fields. The sensitivity of the three peaks of this triple-band absorber to the surrounding is 72, 103.5, 139.5 GHz/RIU, respectively. In addition, the absorber is polarization insensitive because of the symmetric configuration. The absorber can simultaneously exhibit high absorption effect at incident angles up to 60° for transverse electric (TE) polarization and 70° for transverse magnetic (TM) polarization. This presented terahertz metamaterial absorber with a triple-band absorption and easy fabrication can find important applications in biological sensing, THz imaging, filter and optical communication.

How Phillips saw the light

2020 ◽  
Vol 36 (8) ◽  
pp. 29-31
Keyword(s):  
Design Methodology ◽  
Reading Time ◽  
Daily Basis ◽  
Business World ◽  
Content Type ◽  
Freak Show ◽  
The World ◽  
Pertinent Information ◽  
The One ◽  
Practical Implications

Purpose Reviews the latest management developments across the globe and pinpoints practical implications from cutting-edge research and case studies. Design/methodology/approach This briefing is prepared by an independent writer who adds their own impartial comments and places the articles in context. Findings The problem with developing a reputation of being something of an oracle in the business world is that all of a sudden, everyone expects you to pull off the trick of interpreting the future on a daily basis. Like a freak show circus act or one-hit wonder pop singer, people expect you to perform when they see you, and they expect you to perform the thing that made you famous, even if it is the one thing in the world you don’t want to do. And when you fail to deliver on these heightened expectations, you are dismissed as a one trick pony, however good that trick is in the first place. Originality/value The briefing saves busy executives and researchers hours of reading time by selecting only the very best, most pertinent information and presenting it in a condensed and easy-to-digest format.

PROMETHEE-based ranking of project managers based on the five personality traits

Kybernetes ◽  
2019 ◽  
Vol 49 (4) ◽  
pp. 1083-1102
Author(s):  
Georgios N. Aretoulis ◽  
Jason Papathanasiou ◽  
Fani Antoniou
Keyword(s):  
Personality Traits ◽  
Questionnaire Survey ◽  
Multicriteria Decision Making ◽  
Project Managers ◽  
Preference Ranking ◽  
Infrastructure Projects ◽  
Public Infrastructure ◽  
Content Type ◽  
The One ◽  
Selection Of

Purpose This paper aims to rank and identify the most efficient project managers (PMs) based on personality traits, using Preference Ranking Organization METHod for Enrichment Evaluations (PROMETHEE) methodology. Design/methodology/approach The proposed methodology relies on the five personality traits. These were used as the selection criteria. A questionnaire survey among 82 experienced engineers was used to estimate the required weights per personality trait. A second two-part questionnaire survey aimed at recording the PMs profile and assess the performance of personality traits per PM. PMs with the most years of experience are selected to be ranked through Visual PROMETHEE. Findings The findings suggest that a competent PM is the one that scores low on the “Neuroticism” trait and high especially on the “Conscientiousness” trait. Research limitations/implications The research applied a psychometric test specifically designed for Greek people. Furthermore, the proposed methodology is based on the personality characteristics to rank the PMs and does not consider the technical skills. Furthermore, the type of project is not considered in the process of ranking PMs. Practical implications The findings could contribute in the selection of the best PM that maximizes the project team’s performance. Social implications Improved project team communication and collaboration leading to improved project performance through better communication and collaboration. This is an additional benefit for the society, especially in the delivery of public infrastructure projects. A lot of public infrastructure projects deviate largely as far as cost and schedule is concerned and this is an additional burden for public and society. Proper project management through efficient PMs would save people’s money and time. Originality/value Identification of the best PMbased on a combination of multicriteria decision-making and psychometric tests, which focus on personality traits.

Compact dual and triple band antennas for 5G-IOT applications

2021 ◽  
pp. 1-8
Author(s):  
Ruchi ◽  
Amalendu Patnaik ◽  
M. V. Kartikeyan
Keyword(s):  
Microwave Frequency ◽  
Mobile Internet ◽  
Dual Band ◽  
Impedance Bandwidth ◽  
Printed Antenna ◽  
Iot Applications ◽  
Multiband Antennas ◽  
New Radio ◽  
Compact Size ◽  
Triple Band

Abstract Designing miniaturized multiband antennas to cover both the 5G new radio frequencies (FR1 and FR2) simultaneously is a challenge for wireless communication researchers. This paper presents two antenna designs : a dual-band printed antenna of size 18 × 16 × 0.285 mm3 operating at FR1–5.8 GHz and FR2–28 GHz and a triple-band printed antenna with dimensions 30 × 25 × 0.543 mm3 operating at FR1–3.5 GHz and 5.8 GHz (sub-6 GHz microwave frequency bands) and FR2–28 GHz (mm-wave frequency band). The final projected triple-band antenna has a compact size with an impedance bandwidth of 12.71%, 11.32%, and 18.3% at 3.5 GHz, 5.8 GHz, and 28 GHz, respectively with the corresponding gain of 1.86 dB, 2.55 dB, and 4.41 dB. The measured radiation characteristics of the fabricated prototypes show that the proposed designs are suitable for trendy 5G-RFID and mobile Internet of things (IoT) applications.

scholarly journals A Multiband Antenna Stacked with Novel Metamaterial SCSRR and CSSRR for WiMAX/WLAN Applications

Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 113
Author(s):  
Rajiv Mohan David ◽  
Mohammad Saadh AW ◽  
Tanweer Ali ◽  
Pradeep Kumar
Keyword(s):  
Split Ring Resonator ◽  
Unit Cell ◽  
Ring Resonators ◽  
Split Ring ◽  
Medium Theory ◽  
High Frequency Structure Simulator ◽  
Dimension Analysis ◽  
Unit Cells ◽  
Coaxial Feed ◽  
Triple Band

This paper presents an innovative method for the design of a triple band meta-mode antenna. This unique design of antenna finds application in a particular frequency band of WLAN and WiMAX. This antenna comprises of a square complimentary split ring resonator (SCSRR), a coaxial feed, and two symmetrical comb shaped split ring resonators (CSSRR). The metamaterial unit cell SCSRR independently gains control in the band range 3.15–3.25 GHz (WiMAX), whereas two symmetrical CSSRR unit cell controls the band in the ranges 3.91–4.01 GHz and 5.79–5.94 GHz (WLAN). This design methodology and the study of the suggested unit cells structure are reviewed in classical waveguide medium theory. The antenna has a miniaturized size of only 0.213λ0 × 0.192λ0 × 0.0271λ0 (20 × 18 × 2.54 mm3, where λ0 is the free space wavelength at 3.2 GHz). The detailed dimension analysis of the proposed antenna and its radiation efficiency are also presented in this paper. All the necessary simulations are carried out in High Frequency Structure Simulator (HFSS) 13.0 tool.

scholarly journals Beyond agency and stewardship theory: shareholder–manager relationships and governance structures in family firms

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ann Sophie K. Löhde ◽  
Giovanna Campopiano ◽  
Andrea Calabrò
Keyword(s):  
Social Exchange ◽  
Family Business ◽  
Social Exchange Theory ◽  
Family Firms ◽  
Governance Structure ◽  
Managerial Behavior ◽  
Exchange System ◽  
Content Type ◽  
The One ◽  
Over Time

PurposeChallenging the static view of family business governance, we propose a model of owner–manager relationships derived from the configurational analysis of managerial behavior and change in governance structure.Design/methodology/approachStemming from social exchange theory and building on the 4C model proposed by Miller and Le Breton-Miller (2005), we consider the evolving owner–manager relationship in four main configurations. On the one hand, we account for family businesses shifting from a generalized to a restricted exchange system, and vice versa, according to whether a family manager misbehaves in a stewardship-oriented governance structure or a nonfamily manager succeeds in building a trusting relationship in an agency-oriented governance structure. On the other hand, we consider that family firms will strengthen a generalized exchange system, rather than a restricted one, according to whether a family manager contributes to the stewardship-oriented culture in the business or a nonfamily manager proves to be driven by extrinsic rewards. Four scenarios are analyzed in terms of the managerial behavior and governance structure that characterize the phases of the relationship between owners and managers.FindingsVarious factors trigger managerial behavior, making the firm deviate from or further build on what is assumed by stewardship and agency theories (i.e. proorganizational versus opportunistic behavior, respectively), which determine the governance structure over time. Workplace deviance, asymmetric altruism and patriarchy on the one hand, and proorganizational behavior, relationship building and long-term commitment on the other, are found to determine how the manager behaves and thus characterize the owner's reactions in terms of governance mechanisms. This enables us to present a dynamic view of governance structures, which adapt to the actual attitudes and behaviors of employed managers.Research limitations/implicationsAs time is a relevant dimension affecting individual behavior and triggering change in an organization, one must consider family business governance as being dynamic in nature. Moreover, it is not family membership that determines the most appropriate governance structure but the owner–manager relationship that evolves over time, thus contributing to the 4C model.Originality/valueThe proposed model integrates social exchange theory and the 4C model to predict changes in governance structure, as summarized in the final framework we propose.

scholarly journals Investigation on the Optical Dual-band Absorption Enhancement for Graphene Photodetector

2021 ◽  
pp. 104747
Author(s):  
Haixia Liu ◽  
Shashi Zhang ◽  
Hao Ding ◽  
Wei Sun ◽  
Lichen Sun
Keyword(s):  
Dual Band ◽  
Absorption Enhancement ◽  
Band Absorption

Subaltern mediators in the digital landscape

Target ◽  
2017 ◽  
Vol 29 (2) ◽  
pp. 319-338 ◽  
Author(s):  
Teresa Iribarren
Keyword(s):  
Cultural Capital ◽  
Web 2.0 ◽  
The Other ◽  
The Internet ◽  
Lingua Franca ◽  
Content Type ◽  
For Profit ◽  
Long Run ◽  
The One ◽  
Digital Landscape

This article explores translational literary Web 2.0 practices and user-generated cultural creations on the Internet, focusing on video poetry that re-creates canonical poets’ bodies of work. It will be argued that the use of for-profit platforms like YouTube and Vimeo by indie creators and translators of video poetry favours the emergence of new translational attitudes, practices and objects that have positive but also contentious effects. One the one hand, these online mediators explore new poetic expressions and tend to make the most of the potential for dissemination of poetic heritage, providing visibility to non-hegemonic literatures. On the other hand, however, these translational digitally-born practices and creations by voluntary and subaltern mediators might reinforce the hegemonic position of large American Internet corporations at the risk of commodifying cultural capital, consolidating English as a lingua franca and perhaps, in the long run, even fostering a potentially monocultural and internationally homogeneous aesthetics.

A novel parameterized digital-mask generation method for projection stereolithography in tissue engineering

2018 ◽  
Vol 24 (6) ◽  
pp. 935-944 ◽  
Author(s):  
Mingke Li ◽  
Wangyu Liu
Keyword(s):  
Computer Aided Design ◽  
Boundary Region ◽  
Additive Manufacture ◽  
3D Scaffold ◽  
Content Type ◽  
Parameterized Design ◽  
High Efficient ◽  
Unit Cells ◽  
Conventional Methods ◽  
Projection Stereolithography

PurposeThe purpose of this paper is to present the novel parameterized digital-mask generation method which is aimed at enhancing bio-scaffold’s fabricating efficiency with digital micro-mirror device (DMD)-based systems.Design/methodology/approachA method to directly generate the digital masks of bio-scaffolds without modeling the entire 3D scaffold models is presented. In most of the conventional methods, it is inefficient to dynamically modify the size of the structural unit cells during design, because it relies more or less on commercial computer aided design (CAD) platforms. The method proposed in this paper can achieve high efficient parameterized design, and it is independent from any CAD platforms. The generated masks in binary bitmap format can be used by the DMD-based to achieve scaffold’s additive manufacture. In conventional methods, the Boolean operation of the external surface and the internal architectures would result in the damage of unit cells in boundary region. These damaged unit cells not only lose its original mechanical property but also cause numbers of gaps and isolated features that would reduce the geometric accuracy of the fabricated scaffolds; the proposed method in this paper provides an approach to tackle this defect.FindingsThe results show that the proposed method can improve the digital masks generation efficiency.Practical implicationsThe proposed method can serve as an effective supplement to the slicing method in additive manufacture. It also provides a way to design and fabricate scaffolds with heterogeneous architectures.Originality/valueThis paper gives supports to fabricate bio-scaffold with DMD-based systems.

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