scholarly journals Terahertz Beam Steering Concept Based on a MEMS-Reconfigurable Reflection Grating

Sensors ◽  
2020 ◽  
Vol 20 (10) ◽  
pp. 2874
Author(s):  
Xuan Liu ◽  
Lisa Samfaß ◽  
Kevin Kolpatzeck ◽  
Lars Häring ◽  
Jan C. Balzer ◽  
...  
Keyword(s):  
Diffraction Grating ◽  
High Speed ◽  
Beam Steering ◽  
Vertical Displacement ◽  
Grating Period ◽  
Terahertz Waves ◽  
Large Area ◽  
Electrostatic Actuators ◽  
Reflection Gratings ◽  
Reflection Grating

With an increasing number of applications of terahertz systems in industrial fields and communications, terahertz beamforming and beam steering techniques are required for high-speed, large-area scanning. As a promising means for beam steering, micro-electro-mechanical system (MEMS)-based reflection gratings have been successfully implemented for terahertz beam control. So far, the diffraction grating efficiency is relatively low due to the limited vertical displacement range of the reflectors. In this paper, we propose a design for a reconfigurable MEMS-based reflection grating consisting of multiple subwavelength reflectors which are driven by 5-bit, high-throw electrostatic actuators. We vary the number of the reflectors per grating period and configure the throw of individual reflectors so that the reflection grating is shaped as a blazed grating to steer the terahertz beam with maximum diffraction grating efficiency. Furthermore, we provide a mathematical model for calculating the radiation pattern of the terahertz wave reflected by general reflection gratings consisting of subwavelength reflectors. The calculated and simulated radiation patterns of the designed grating show that we can steer the angle of the terahertz waves in a range of up to ± 56.4 ∘ with a maximum sidelobe level of −10 dB at frequencies from 0.3 THz to 1 THz.

scholarly journals Photonics-Assisted Terahertz-Wave Beam Steering and Its Application in Secured Wireless Communication

Photonics ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 9
Author(s):  
Kazutoshi Kato
Keyword(s):  
Wireless Communication ◽  
Power Efficiency ◽  
Electromagnetic Waves ◽  
High Speed ◽  
Phased Array ◽  
Beam Steering ◽  
Terahertz Wave ◽  
Coherent Detection ◽  
Terahertz Waves ◽  
Optical Domain

Beam forming and beam steering are inevitable technologies for the practical application of high-frequency electromagnetic waves. Specifically, beam control technology using a phased array for terahertz waves above 100 GHz is necessary to realize the future of high-speed wireless communication. By photomixing, which is a promising method for generating terahertz waves, the phase of the generated waves can be tuned in the optical domain, so that the beam from the phased array can be controlled by photonics technologies. Directing the beam of a terahertz wave enables wireless communication to be improved not only via an increase in power efficiency but also in security in the physical layer of the wireless transmission. By utilizing this advantage and using coherent detection at the receiver, a secured wireless communication system is proposed, and the fundamental mechanism is demonstrated in a feasibility experiment.

scholarly journals Integration of an InSAR and ANN for Sinkhole Susceptibility Mapping: A Case Study from Kirikkale-Delice (Turkey)

2021 ◽  
Vol 10 (3) ◽  
pp. 119
Author(s):  
Hakan A. Nefeslioglu ◽  
Beste Tavus ◽  
Melahat Er ◽  
Gamze Ertugrul ◽  
Aybuke Ozdemir ◽  
...  
Keyword(s):  
High Speed ◽  
Fundamental Problem ◽  
Vertical Displacement ◽  
Deformation Monitoring ◽  
Susceptibility Mapping ◽  
Susceptibility Map ◽  
Engineering Structures ◽  
Conditioning Factors ◽  
High Deformation ◽  
Settlement Site

Suitable route determination for linear engineering structures is a fundamental problem in engineering geology. Rapid evaluation of alternative routes is essential, and novel approaches are indispensable. This study aims to integrate various InSAR (Interferometric Synthetic Aperture Radar) techniques for sinkhole susceptibility mapping in the Kirikkale-Delice Region of Turkey, in which sinkhole formations have been observed in evaporitic units and a high-speed train railway route has been planned. Nine months (2019–2020) of ground deformations were determined using data from the European Space Agency’s (ESA) Sentinel-1A/1B satellites. A sinkhole inventory was prepared manually using satellite optical imagery and employed in an ANN (Artificial Neural Network) model with topographic conditioning factors derived from InSAR digital elevation models (DEMs) and morphological lineaments. The results indicate that high deformation areas on the vertical displacement map and sinkhole-prone areas on the sinkhole susceptibility map (SSM) almost coincide. InSAR techniques are useful for long-term deformation monitoring and can be successfully associated in sinkhole susceptibility mapping using an ANN. Continuous monitoring is recommended for existing sinkholes and highly susceptible areas, and SSMs should be updated with new results. Up-to-date SSMs are crucial for the route selection, planning, and construction of important transportation elements, as well as settlement site selection, in such regions.

scholarly journals High-speed high-efficiency large-area resonant cavity enhanced p-i-n photodiodes for multimode fiber communications

2001 ◽  
Vol 13 (12) ◽  
pp. 1349-1351 ◽  
Author(s):  
M. Gokkavas ◽  
O. Dosunmu ◽  
M.S. Unlu ◽  
G. Ulu ◽  
R.P. Mirin ◽  
...  
Keyword(s):  
High Speed ◽  
High Efficiency ◽  
Resonant Cavity ◽  
Multimode Fiber ◽  
Large Area ◽  
Fiber Communications

An Investigation onto Polydimethylsiloxane (PDMS) Printing Plate of Multiple Functional Solid Line by Flexographic

2013 ◽  
Vol 844 ◽  
pp. 158-161 ◽  
Author(s):  
M.I. Maksud ◽  
Mohd Sallehuddin Yusof ◽  
M. Mahadi Abdul Jamil
Keyword(s):  
Laser Ablation ◽  
Line Width ◽  
High Speed ◽  
Printed Electronics ◽  
Low Cost ◽  
Flexible Substrates ◽  
Large Area ◽  
Printing Plate ◽  
Roll To Roll ◽  
Printing Processes

Recently low cost production is vital to produce printed electronics by roll to roll manufacturing printing process like a flexographic. Flexographic has a high speed technique which commonly used for printing onto large area flexible substrates. However, the minimum feature sizes achieved with roll to roll printing processes, such as flexographic is in the range of fifty microns. The main contribution of this limitation is photopolymer flexographic plate unable to be produced finer micron range due to film that made by Laser Ablation Mask (LAMs) technology not sufficiently robust and consequently at micron ranges line will not be formed on the printing plate. Hence, polydimethylsiloxane (PDMS) is used instead of photopolymer. Printing trial had been conducted and multiple solid lines successfully printed for below fifty microns line width with no interference between two adjacent lines of the printed images.

scholarly journals Vertically integrated diffractive gratings on photonic crystal surface emitting lasers

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lih-Ren Chen ◽  
Kuo-Bin Hong ◽  
Hsiu-Ling Chen ◽  
Kuan-Chih Huang ◽  
Tien-Chang Lu
Keyword(s):  
Photonic Crystal ◽  
Crystal Surface ◽  
Beam Steering ◽  
Azimuthal Angle ◽  
Three Dimensional ◽  
Grating Period ◽  
Single Chip ◽  
Output Beam ◽  
Optical Elements ◽  
Emitting Lasers

AbstractWe designed and fabricated a photonic crystal surface emitting laser (PCSEL) with vertically integrated diffractive optical elements on their top to study the mechanism of static beam steering on a single chip. The deflected output beam by the self-formed periodic ITO cladding layer of the PCSEL can be further steered by changing the grating period and azimuthal angle of the diffractive gratings relative to the photonic crystal. Through the analysis of photonic band structure and lasing characteristics, the periodic ITO structure is coupled to the photonic crystal band, whereas the integrated grating serves the diffractive function only. The findings pave the way for the design of PCSELs enabling single or multiple output beam with varying direction capability. This type of laser is regarded as an ideal light source for various applications, such as light detection and ranging and three-dimensional sensing systems.

scholarly journals Diffuse Coplanar Surface Barrier Discharge in Artificial Air: Statistical Behaviour of Microdischarges

2014 ◽  
Vol 13 (1) ◽  
Author(s):  
Jan Čech ◽  
Jana Hanusová ◽  
Pavel Sťahel ◽  
Mirko Černák
Keyword(s):  
High Speed ◽  
Barrier Discharge ◽  
Atmospheric Pressure Plasma ◽  
Input Voltage ◽  
Half Period ◽  
Surface Barrier ◽  
Electrical Measurements ◽  
Large Area ◽  
Electrode Gap ◽  
Surface Barrier Discharge

AbstractDiffuse Coplanar Surface Barrier Discharge (DCSBD) is a novel type of atmospheric-pressure plasma source developed for high-speed large-area surface plasma treatments. The statistical behavior of microdischarges of DCSBD generated in artificial air atmosphere was studied using time-correlated optical and electrical measurements. Changes in behavior of microdischarges are shown for various electrode gap widths and input voltage amplitudes. They are discussed in the light of correlation of the number of microdischarges and the number of unique microdischarges’ paths per discharge event.The ‘memory effect’ was observed in the behavior of microdischarges and it manifests itself in a significant number of microdischarges reusing the path of microdischarges from previous half-period. Surprisingly this phenomenon was observed even for microdischarges of the same half-period of the discharge, where mechanisms other than charge deposition have to be involved. The phenomenon of discharge paths reuse is most pronounced for wide electrode

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