scholarly journals Multi-Beam Steering for 6G Communications Based on Graphene Metasurfaces

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4784
Author(s):  
Huifang Ai ◽  
Qianlong Kang ◽  
Wei Wang ◽  
Kai Guo ◽  
Zhongyi Guo
Keyword(s):  
Communication Technology ◽  
Applied Voltage ◽  
High Performance ◽  
Beam Steering ◽  
Metal Substrate ◽  
Far Field ◽  
Great Demand ◽  
Field Distributions ◽  
Dielectric Spacer ◽  
Potential Applications

As communication technology is entering the 6G era, a great demand for high-performance devices operating in the terahertz (THz) band has emerged. As an important part of 6G technology, indoor communication requires multi-beam steering and tracking to serve multi-users. In this paper, we have designed a graphene metasurface that can realize multi-beam steering for directional radiations. The designed metasurface consists of graphene ribbons, dielectric spacer, and metal substrate. By designing the graphene ribbons and controlling the applied voltage on them, we have obtained single-, double-, and triple-beam steering. In addition, we have also numerically calculated the far-field distributions of the steered multi-beam with a diffraction distance of 2 m. Our design has potential applications in future indoor directional 6G communications.

scholarly journals Diffraction engineering for silicon waveguide grating antenna by harnessing bound state in the continuum

Nanophotonics ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 1439-1446
Author(s):  
Hongnan Xu ◽  
Yaocheng Shi
Keyword(s):  
High Performance ◽  
Beam Steering ◽  
Side Wall ◽  
Bound State ◽  
Far Field ◽  
Propagation Length ◽  
Waveguide Grating ◽  
Silicon Waveguide ◽  
Waveguide Width ◽  
The Continuum

AbstractSilicon waveguide grating antennas (SWGAs) have been widely employed to interface the guided and radiation modes in various integrated photonic systems. However, ultrasmall feature sizes or heteromaterial integrations are usually required to obtain long propagation length and small far-field divergence. Moreover, for conventional SWGAs, the diffraction strength is wavelength sensitive, so the output power and far-field divergence will deviate in the beam steering process. In this paper, we propose and demonstrate a novel approach to engineer the diffraction in SWGA by harnessing the bound state in the continuum (BIC). A new degree of freedom is attained in diffraction engineering by introducing the “modified” diffraction formula. The side-wall emission can be dramatically depressed by building the quasi-BIC at critical waveguide width, leading to ultrauniform diffraction. The extremely weak diffraction strength (~3.3 × 10−3 dB/μm) has been experimentally realized for the fabricated device with a large feature size (~60 nm). From the measurement results, one can predict a centimeter-scale propagation length and an ultrasmall divergence (~0.027°). Moreover, the diffraction strength dispersion can be flattened for SWGA with critical waveguide width. Such effect has also been experimentally verified. Our proposed design is the first one that introduces the BIC effect into SWGA optimization, paving the way for precise diffraction engineering and high-performance integrated optical antennas.

Electrochemical Deposition of Polypyrrole Nanostructures for Energy Applications: A Review

2020 ◽  
Vol 16 (4) ◽  
pp. 462-477 ◽  
Author(s):  
Patrizia Bocchetta ◽  
Domenico Frattini ◽  
Miriana Tagliente ◽  
Filippo Selleri
Keyword(s):  
Lithium Batteries ◽  
High Performance ◽  
Relevant Literature ◽  
Chemical Parameters ◽  
Energy Devices ◽  
Energy Applications ◽  
Physico Chemical ◽  
Potential Applications ◽  
Template Free ◽  
Cathodic Polymerization

By collecting and analyzing relevant literature results, we demonstrate that the nanostructuring of polypyrrole (PPy) electrodes is a crucial strategy to achieve high performance and stability in energy devices such as fuel cells, lithium batteries and supercapacitors. In this critic and comprehensive review, we focus the attention on the electrochemical methods for deposition of PPy, nanostructures and potential applications, by analyzing the effect of different physico-chemical parameters, electro-oxidative conditions including template-based or template-free depositions and cathodic polymerization. Diverse interfaces and morphologies of polymer nanodeposits are also discussed.

scholarly journals Changes in Optical Properties upon Dye–Clay Interaction: Experimental Evaluation and Applications

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 197
Author(s):  
Giorgia Giovannini ◽  
René M. Rossi ◽  
Luciano F. Boesel
Keyword(s):  
Optical Properties ◽  
Hybrid Materials ◽  
High Performance ◽  
Fluorescent Properties ◽  
Chemical Mechanisms ◽  
Strong Electrostatic Interaction ◽  
Potential Applications ◽  
Photochemical Properties ◽  
Physical And Chemical ◽  
The Relationship

The development of hybrid materials with unique optical properties has been a challenge for the creation of high-performance composites. The improved photophysical and photochemical properties observed when fluorophores interact with clay minerals, as well as the accessibility and easy handling of such natural materials, make these nanocomposites attractive for designing novel optical hybrid materials. Here, we present a method of promoting this interaction by conjugating dyes with chitosan. The fluorescent properties of conjugated dye–montmorillonite (MMT) hybrids were similar to those of free dye–MMT hybrids. Moreover, we analyzed the relationship between the changes in optical properties of the dye interacting with clay and its structure and defined the physical and chemical mechanisms that take place upon dye–MMT interactions leading to the optical changes. Conjugation to chitosan additionally ensures stable adsorption on clay nanoplatelets due to the strong electrostatic interaction between chitosan and clay. This work thus provides a method to facilitate the design of solid-state hybrid nanomaterials relevant for potential applications in bioimaging, sensing and optical purposes.

scholarly journals A Review on the Development of Rotman Lens Antenna

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Shruti Vashist ◽  
M. K. Soni ◽  
P. K. Singhal
Keyword(s):  
High Performance ◽  
Beam Steering ◽  
Phase Error ◽  
Antenna System ◽  
Surveillance Systems ◽  
Electronic Warfare ◽  
Design Concepts ◽  
Low Profile ◽  
True Time ◽  
The One

Rotman lenses are the beguiling devices used by the beamforming networks (BFNs). These lenses are generally used in the radar surveillance systems to see targets in multiple directions due to its multibeam capability without physically moving the antenna system. Now a days these lenses are being integrated into many radars and electronic warfare systems around the world. The antenna should be capable of producing multiple beams which can be steered without changing the orientation of the antenna. Microwave lenses are the one who support low-phase error, wideband, and wide-angle scanning. They are the true time delay (TTD) devices producing frequency independent beam steering. The emerging printed lenses in recent years have facilitated the advancement of designing high performance but low-profile, light-weight, and small-size and networks (BFNs). This paper will review and analyze various design concepts used over the years to improve the scanning capability of the lens developed by various researchers.

A DoD Perspective on Left Handed Negative Index Materials and Potential Applications

2006 ◽  
Vol 919 ◽  
Author(s):  
Valerie Browning ◽  
Minas H Tanielian ◽  
Richard W. Ziolkowski ◽  
Nader Engheta ◽  
David R. Smith
Keyword(s):  
Composite Structures ◽  
Beam Steering ◽  
Electromagnetic Response ◽  
Electromagnetic Spectrum ◽  
Negative Index ◽  
Negative Index Materials ◽  
Left Handed ◽  
Potential Applications ◽  
Novel Approaches ◽  
Electromagnetic Transport

AbstractIn the quest for ever smaller, lighter weight, and conformal components and devices for radar and communication applications, researchers in the RF community have increasingly turned to artificially engineered, composite structures (or “metamaterials”) in order to exploit the extraordinary electromagnetic response these materials offer. One particularly promising class of metamaterials that has recently received a great deal of attention are “left-handed” or negative index materials. Because these metamaterials exhibit the unique ability to bend and focus light in ways no other conventional materials can, they hold great potential for enabling a number of innovative lens and antenna structures for a broad range of commercial and DoD relevant applications. Exploring the possible implementation of negative index materials for such applications will require significant enhancements in the properties of existing Negative Index Materials (NIM) (bandwidth, loss, operational frequency, etc.), as well as improved understanding of the physics of their electromagnetic transport properties. For this reason the Defense Advanced Research Project Agency (DARPA) has initiated a program that seeks to further develop and demonstrate NIM for future DoD missions including, but not limited to, the following: 1) lightweight, compact lenses with improved optics; 2) sub wavelength/high resolution imaging across the electromagnetic spectrum; 3) novel approaches to beam steering for radar, RF, and/or optical communications; and 4) novel approaches for integrating optics with semiconductor electronics. A brief overview of the salient properties of NIM will be presented as well as a general discussion of a few of their potential applications.

Innovative High Density Power Module for E-Scooter Motor Using a High Performance Insulated Metal Substrate

2021 ◽  
Author(s):  
Kuo-Shu Kao ◽  
Sheng-Tsai Wu ◽  
Ji-Yuan Syu ◽  
Tao-Chih Chang ◽  
Chang-Chun Lee
Keyword(s):  
High Performance ◽  
Metal Substrate ◽  
High Density ◽  
Power Module

Application potential of textile reinforcement in concrete construction for infrastructure buildings: environmental performance and availability

2021 ◽  
Author(s):  
Sara Reichenbach ◽  
Benjamin Kromoser ◽  
Philipp Preinstorfer ◽  
Tobias Huber
Keyword(s):  
High Performance ◽  
Construction Material ◽  
Limit State ◽  
Carbon Dioxide Emission ◽  
Resource Consumption ◽  
Ultimate Limit State ◽  
Textile Reinforced Concrete ◽  
Potential Applications ◽  
Application Potential ◽  
Ultimate Limit

<p>With the building industry being one of the main sources of carbon dioxide emission worldwide and concrete being the main construction material, new strategies have to be developed to reduce the carbon footprint thereof. The use of high-performance materials in structural concrete, as for example textile-reinforced concrete (TRC), seems to allow for a reduction of the resource consumption and the carbon emissions. The present paper addresses potential applications of TRC examining the global warming potential (GWP) of a rail platform barrier. The resource consumption is depicted in a parametrical study in terms of the necessary component height and reinforcement area considering both the serviceability limit state (SLS) as well as the ultimate limit state (ULS). The results clearly indicate an achievable reduction of the GWP during construction when using textile reinforcement made of high-performance fibres. Furthermore, an analysis of the European market was conducted to prove the availability of this new reinforcement type. </p>

scholarly journals Palm Oil Carotenoids

1994 ◽  
Vol 15 (2) ◽  
pp. 1-8 ◽  
Author(s):  
Choo Yuen May
Keyword(s):  
Palm Oil ◽  
High Performance ◽  
Elaeis Guineensis ◽  
Provitamin A ◽  
Carotenoid Content ◽  
Crude Palm Oil ◽  
Alkyl Esters ◽  
Red Palm Oil ◽  
Potential Applications ◽  
Nutritional Effects

Crude palm oil is the richest natural plant source of carotenoids in terms of retinol (provitamin A) equivalent. This article reports on » the carotenoids found in palm oil, its fractions, byproducts, and derivatives from the Elaeis guineensis and E. oleifera palms, including their hybrids and a back-cross, as well as the carotenoids of pressed palm fibres, second-pressed oil, palm leaves, and palm-derived alkyl esters; » two novel procedures for preparing highly concentrated sources of carotenoids (>80,000 ppm), by recovery by palm alkyl esters, and by retention and concentration in deacidified and deodorized red palm oil; » the carotenoid content and profiles of the above sources obtained by high-performance liquid chromatography; and » nutritional effects of palm oil carotenoids and their potential applications for health promotion and disease prevention.

scholarly journals VINCI®, the european reference for ariane 6 upper stage cryogenic propulsive system

2019 ◽  
Author(s):  
P. Alliot ◽  
J.-F. Delange ◽  
V. De Korver ◽  
J.-M. Sannino ◽  
A. Lekeux ◽  
...  
Keyword(s):  
High Performance ◽  
Design Review ◽  
Design Concepts ◽  
Critical Design ◽  
Potential Applications ◽  
Upper Stage ◽  
Command Systems ◽  
Engine Development ◽  
Orbital Spacecraft ◽  
Government Level

The intent of this publication is to provide an overview of the development of the VINCI® engine over the period 2014–2015. The VINCI® engine is an upper stage, cryogenic expander cycle engine. It combines the required features of this cycle, i. e., high performance chamber cooling and high performance hydrogen turbopump, with proven design concepts based on the accumulated experience from previous European cryogenic engines such as the HM7 and the VULCAIN®. In addition, its high performance and reliability, its restart and throttle capability offer potential applications on various future launcher upper stages as well as orbital spacecraft. At the end of 2014, the VINCI® successfully passed the Critical Design Review that was held after the major subsystem (combustion chamber, fuel and oxygen turbopump) had passed their own Critical Design Review all along the second half of 2014. In December, a Ministerial Conference at government level gave priority to the Ariane 6 program as Europe future launcher. In the framework of this decision, VINCI® was confirmed as the engine to equip Ariane 6 cryogenic upper stage engine. This publication shows how the VINCI development is progressing toward qualification, and also how the requirements of the new Ariane 6 configuration taken into account, i. e., offering new opportunities to the launch system and managing the new constraints. Moreover, the authors capitalize on the development already achieved for the evolution of Ariane 5. In parallel to completing the engine development and qualification, the configuration and the equipment of the propulsive system for Ariane 6 such as the components of the pressurization and helium command systems, board to ground coupling equipment, are being defined.

scholarly journals OPEN URBAN AND FOREST DATASETS FROM A HIGH-PERFORMANCE MOBILE MAPPING BACKPACK – A CONTRIBUTION FOR ADVANCING THE CREATION OF DIGITAL CITY TWINS

2021 ◽  
Vol XLIII-B1-2021 ◽  
pp. 125-131
Author(s):  
S. Blaser ◽  
J. Meyer ◽  
S. Nebiker
Keyword(s):  
High Performance ◽  
City Centre ◽  
Data Sets ◽  
High Quality ◽  
Mobile Mapping ◽  
Street Level ◽  
Localization And Mapping ◽  
Digital Twins ◽  
Potential Applications ◽  
The Creation

Abstract. With this contribution, we describe and publish two high-quality street-level datasets, captured with a portable high-performance Mobile Mapping System (MMS). The datasets will be freely available for scientific use. Both datasets, from a city centre and a forest represent area-wide street-level reality captures which can be used e.g. for establishing cloud-based frameworks for infrastructure management as well as for smart city and forestry applications. The quality of these data sets has been thoroughly evaluated and demonstrated. For example, georeferencing accuracies in the centimetre range using these datasets in combination with image-based georeferencing have been achieved. Both high-quality multi sensor system street-level datasets are suitable for evaluating and improving methods for multiple tasks related to high-precision 3D reality capture and the creation of digital twins. Potential applications range from localization and georeferencing, dense image matching and 3D reconstruction to combined methods such as simultaneous localization and mapping and structure-from-motion as well as classification and scene interpretation. Our dataset is available online at: https://www.fhnw.ch/habg/bimage-datasets

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