scholarly journals A high-efficiency and ultrathin transmission-type circular polarization converter based on surface structure

2021 ◽  
Vol 8 ◽  
pp. 4
Author(s):  
Peng Xu ◽  
Wei Xiang Jiang ◽  
Xiao Cai ◽  
Yue Gou ◽  
Tie Jun Cui
Keyword(s):  
High Efficiency ◽  
Transmission Mode ◽  
Polarization Converter ◽  
Periodic Surface ◽  
Circularly Polarized ◽  
Left Handed ◽  
Via Holes ◽  
Working Frequency ◽  
The Right ◽  
Good Agreement

In this paper, we propose, design and fabricate a kind of ultrathin and high-efficiency circularly polarization converter based on artificially engineered surfaces in the transmission mode. The converter is composed of double-layer periodic surface structures with cross slots. The top and bottom layers are printed on both sides of the F4B substrate and connected by metallic via holes. The proposed converter can transform the right-handed circularly polarized incident electromagnetic (EM) wave to a left-handed circularly-polarized one with near-unity efficiency in the transmission mode, or vice versa. We explain the conversion mechanism based on numerical simulations and equivalent circuit (EC) theory. The measured result has a good agreement with the simulated one in the working frequency band. Such ultrathin polarization converters can be used in wireless microwave communication, remote sensing, and EM imaging where circularly polarization diversity is needed.

scholarly journals Dual-Circularly Polarized 60 GHz Beam-Steerable Antenna Array with 8 × 8 Butler Matrix

2020 ◽  
Vol 10 (7) ◽  
pp. 2413 ◽  
Author(s):  
Yuntae Park ◽  
Jihoon Bang ◽  
Jaehoon Choi
Keyword(s):  
Circular Polarization ◽  
Antenna Array ◽  
Mutual Coupling ◽  
Beam Steering ◽  
60 Ghz ◽  
Circularly Polarized ◽  
Butler Matrix ◽  
Left Handed ◽  
Steerable Antenna ◽  
The Right

A beam-steerable dual-circularly polarized 60 GHz antenna array is proposed. A 1 × 4 dual-fed stacked patch antenna array is integrated with an 8 × 8 Butler matrix. By utilizing the 8 × 8 Butler matrix, the proposed antenna array generates dual-circular polarization with beam-steering capability. The proposed antenna array system demonstrates good reflection coefficients in the frequency band ranging from 55.3 GHz to 64.9 GHz and has a mutual coupling of less than −10 dB over the frequency range of 57.5 GHz–63.2 GHz. At 60 GHz, the maximum gains and beam-steering angles for input ports 2, 4, 5, and 7 are 9.39 dBi at −38°, 10.67 dBi at −11°, 10.63 dBi at +11°, and 9.38 dBi at +39°, respectively. It is also demonstrated that the dual-polarization is well formed by switching the excitation ports. The right-handed circular polarization (RHCP) is formed when four ports from port 1 to port 4 are excited and left-handed circular polarization (LHCP) is formed when four ports from port 5 to port 8 are excited. The proposed antenna array system could be a good candidate for millimeter-wave 5G applications that require wide beam coverage and polarization diversity.

scholarly journals A Miniaturized Circularly-Polarized Antenna for In-Body Wireless Communications

Micromachines ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 70 ◽  
Author(s):  
Yi Fan ◽  
Xiongying Liu ◽  
Jiming Li ◽  
Tianhai Chang
Keyword(s):  
Wireless Communications ◽  
Ex Vivo ◽  
Axial Ratio ◽  
Impedance Bandwidth ◽  
Circularly Polarized ◽  
Ism Band ◽  
Left Handed ◽  
Current Path ◽  
Implantable Antenna ◽  
Good Agreement

A novel miniaturized single-fed circularly-polarized (CP) microstrip patch antenna operating in the Industrial, Scientific, Medical (ISM) band of 2.40–2.48 GHz, is comprehensively proposed for implantable wireless communications. By employing reactive loading in the arrow-shaped slotted patch to form slow wave effect and embedding V-shaped slots into patch to lengthen the current path, the proposed implantable antenna is minimized with the overall dimensions of 9.2 mm × 9.2 mm × 1.27 mm. The radiation patterns of the proposed antenna illustrate the performance of left-handed circular polarization. The simulated results show that an impedance bandwidth of 7.2% (2.39–2.57 GHz) and an axial ratio bandwidth of 3.7% (2.39–2.48 GHz) at the ISM band are achieved, respectively. Ex vivo measured results are in good agreement with the corresponding simulated ones.

scholarly journals Determination of Absolute Structure of Chiral Crystals Using Three-Wave X-ray Diffraction

Crystals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1389
Author(s):  
Ksenia Kozlovskaya ◽  
Elena Ovchinnikova ◽  
Jun Kokubun ◽  
Andrei Rogalev ◽  
Fabrice Wilhelm ◽  
...  
Keyword(s):  
Bragg Reflection ◽  
Quantitative Description ◽  
X Rays ◽  
Circularly Polarized ◽  
X Ray ◽  
Left Handed ◽  
The Difference ◽  
The Right ◽  
Chiral Crystals ◽  
Absolute Structure

We propose a new method to determine the absolute structure of chiral crystals, which is based on the chiral asymmetry of multiple scattering diffraction. It manifests as a difference in the azimuthal dependence of the forbidden Bragg reflection intensity measured with left and right circularly polarized X-ray beams. Contrary to the existing ones, the suggested method does not use X-ray anomalous dispersion. The difference between the Renninger scans with circularly polarized X-rays has been experimentally demonstrated for the 001 reflection intensities in the right- and left-handed quartz single crystals. A Jmulti-based code on model-independent three-wave-diffraction approach has been developed for quantitative description of our experimental results. The proposed method can be applied to various structures including opaque, organic and monoatomic crystals, even with only light elements. To determine the type of isomer, the Renninger plot of a single forbidden reflection is sufficient.

Broadband and High-efficiency Linear Polarization Converter Based on Reflective Metasurface

2020 ◽  
Author(s):  
Yaxian Guo ◽  
◽  
Jianchun Xu ◽  
Chuwen Lan ◽  
Ke Bi ◽  
...  
Keyword(s):  
Linear Polarization ◽  
High Efficiency ◽  
Polarization Converter

Определение ведущей руки в судебно-медицинской практике с помощью стоматологического индекса КПУ

2020 ◽  
pp. 46-48
Keyword(s):  
Dental Caries ◽  
Forensic Medicine ◽  
Left Handed ◽  
Forensic Practice ◽  
The World ◽  
Medical Identification ◽  
The Right

In current forensic medicine practice, the need for the development of new, scientifically based approaches and methods of forensic medical identification is still very important. The number of left-handed people in the world varies from 5 to 30 %, and it can be useful in forensic practice. The possibility of establishing a dominating hand based on the intensity of dental caries (CFE - CARIES-FILLIN-EXTRACTION index) was studied. Taking into consideration the intensity of caries damage to the teeth on the right and left sides of right-handed, left-handed and ambidextras people, we offered and calculated the CFE difference index: «CFE on the right – CFE on the left». Significant differences in the CFE indexes can help to determine what hand has been predominant and it might be useful for forensic specialists.

ANALYSIS OF THE COMPETITIVE ACTIVITIES OF THE WORLD STRONGEST BELT WRESTLERS

2020 ◽  
Vol 8 (1) ◽  
pp. 38-45
Author(s):  
Mariya Sedunova ◽  
Liliya Konovalova
Keyword(s):  
Female Athletes ◽  
Group Differences ◽  
Men And Women ◽  
World Championship ◽  
Left Handed ◽  
Competitive Activity ◽  
The World ◽  
The Right ◽  
Competitive Activities ◽  
Distinguishing Features

International potential and consequent greater competition in belt wrestling increase the significance of assessing quantitative and qualitative indicators of competitive activity of the strongest wrestlers in the world. It is important to identify the sport development trends and to search for effective ways and tools for achievement of the sport excellence. Purpose: to reveal the features of efficient competitive activities of the world leading wrestlers on the basis of analysis of group differences in technical and tactical excellence indicators. Materials and methods of research. We analyzed videos of 285 events with participation of 197 wrestlers competing at the Belt Wrestling World Championship 2019 in Kazan. We registered the following indicators of competitive activity: the total and average number of fighting techniques, including techniques executed to the right and to the left side within 4 minutes of combat; number and types of technical actions of competition winners among men and women. Research results and discussion. The paper focuses on the comparative analysis of technical and tactical skills of men and women, the winners of the Belt Wrestling World Championship. The research revealed distinguishing features of the winner’s technical toolkit including the diversity of technical and tactical actions, a balance in the knowledge of the right and left-handed techniques. At the same time, the analysis of technical and tactical actions in women wrestling shows the backlog of female athletes in these components of technical fitness.

Modulation instability in nonlinear chiral fiber

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Demissie Jobir Gelmecha ◽  
Ram Sewak Singh
Keyword(s):  
Theoretical Model ◽  
Numerical Simulations ◽  
Pulse Propagation ◽  
Modulation Instability ◽  
Constitutive Relations ◽  
Gain Spectrum ◽  
Circularly Polarized ◽  
Left Handed ◽  
Simulation Results ◽  
The Difference

AbstractIn this paper, the rigorous derivations of generalized coupled chiral nonlinear Schrödinger equations (CCNLSEs) and their modulation instability analysis have been explored theoretically and computationally. With the consideration of Maxwell’s equations and Post’s constitutive relations, a generalized CCNLSE has been derived, which describes the evolution of left-handed circularly polarized (LCP) and right-handed circularly polarized (RCP) components propagating through single-core nonlinear chiral fiber. The analysis of modulation instability in nonlinear chiral fiber has been investigated starting from CCNLSEs. Based on a theoretical model and numerical simulations, the difference on the modulation instability gain spectrum in LCP and RCP components through chiral fiber has been analyzed by considering loss and chirality into account. The obtained simulation results have shown that the loss distorts the sidebands of the modulation instability gain spectrum, while chirality modulates the gain for LCP and RCP components in a different manner. This suggests that adjusting chirality strength may control the loss, and nonlinearity simultaneously provides stable modulated pulse propagation.

scholarly journals High-Efficiency Polarizer Reflectarray Antennas for Data Transmission Links from a CubeSat

Electronics ◽  
2021 ◽  
Vol 10 (15) ◽  
pp. 1802
Author(s):  
Eduardo Martinez-de-Rioja ◽  
Daniel Martinez-de-Rioja ◽  
Rafael López-Sáez ◽  
Ignacio Linares ◽  
Jose A. Encinar
Keyword(s):  
Circular Polarization ◽  
Data Transmission ◽  
High Efficiency ◽  
High Gain ◽  
Dual Band ◽  
Left Handed ◽  
Linearly Polarized ◽  
Flat Profile ◽  
First Time ◽  
Collimated Beam

This paper presents two designs of high-efficiency polarizer reflectarray antennas able to generate a collimated beam in dual-circular polarization using a linearly polarized feed, with application to high-gain antennas for data transmission links from a Cubesat. First, an 18 cm × 18 cm polarizer reflectarray operating in the 17.2–22.7 GHz band has been designed, fabricated, and tested. The measurements of the prototype show an aperture efficiency of 52.7% for right-handed circular polarization (RHCP) and 57.3% for left-handed circular polarization (LHCP), both values higher than those previously reported in related works. Then, a dual-band polarizer reflectarray is presented for the first time, which operates in dual-CP in the frequency bands of 20 GHz and 30 GHz. The proposed antenna technology enables a reduction of the complexity and cost of the feed chain to operate in dual-CP, as a linear-to-circular polarizer is no longer required. This property, combined with the lightweight, flat profile and low fabrication cost of printed reflectarrays, makes the proposed antennas good candidates for Cubesat applications.

Disorientation of Cs(62P1/2) atoms, induced in collisions with noble gases

1976 ◽  
Vol 54 (7) ◽  
pp. 748-752 ◽  
Author(s):  
B. Niewitecka ◽  
L. Krause
Keyword(s):  
Cross Sections ◽  
Noble Gas ◽  
Zero Magnetic Field ◽  
Zero Field ◽  
Buffer Gas ◽  
Resonance Fluorescence ◽  
Circularly Polarized ◽  
Low Field ◽  
Good Agreement ◽  
Gas Pressures

The disorientation of 62P1/2 cesium atoms, induced in collisions with noble gas atoms in their ground states, was systematically investigated by monitoring the depolarization of cesium resonance fluorescence in relation to noble gas pressures. The Cs atoms, contained together with a buffer gas in a fluorescence cell and located in zero magnetic field, were excited and oriented by irradiation with circularly polarized 8943 Å resonance radiation, and the resonance fluorescence, emitted in an approximately backward direction, was analyzed with respect to circular polarization. The experiments yielded the following disorientation cross sections which have been corrected for the effects of nuclear spin: Cs–He: 4.9 ± 0.7 Å2; Cs–Ne: 2.1 ± 0.3 Å2; Cs–Ar: 5.6 ± 0.8 Å2; Cs–Kr: 5.8 ± 0.9 Å2; Cs–Xe: 6.3 ± 0.9 Å2. The results are in good agreement with most of the available zero-field and low-field data.

scholarly journals Design of a High-Power High-Efficiency Multi-Receiver Wireless Power Transfer System

Electronics ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1308
Author(s):  
Yuyu Zhu ◽  
Hanyu Zhang ◽  
Zuming Wang ◽  
Xin Cao ◽  
Renyin Zhang
Keyword(s):  
Power Distribution ◽  
Power Flow ◽  
High Efficiency ◽  
Control Method ◽  
Experimental Models ◽  
Wireless Power ◽  
Multiple Receivers ◽  
Combined Operation ◽  
Wireless Power Transfer System ◽  
Good Agreement

This paper proposes a new control method to regulate the power flow into multiple receivers. This system consists of one transmitter controller and three receiver controllers. They work independently to decide the power distribution with their combined operation. The simulated and experimental models have been built, and the experimental results are in good agreement with the theoretical analysis results. The proposed method is robust, flexible, and generalizable, and can be employed under various wireless charging conditions.

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