Design of All-Dielectric Ultra-Wideband Transparent Water-Based Absorber

2021 ◽  
Author(s):  
Yi Lu ◽  
Juan Chen ◽  
Jianxing Li
Keyword(s):  
Thermal Stability ◽  
Energy Harvesting ◽  
Frequency Band ◽  
Oblique Incidence ◽  
Ultra Wideband ◽  
Test Results ◽  
Good Thermal Stability ◽  
Water Based ◽  
Simulation Results ◽  
Good Agreement

Abstract In this paper, an all-dielectric water-based transparent absorber is proposed. It is composed of transparent resin material filled with water, thus achieving the characteristics of all-dielectric and transparency. The simulation results show that the proposed absorber can achieve the absorptivity of more than 90% in the frequency band of 7.28-28.22GHz, and has good thermal stability and oblique incidence angular stability. The thickness of the absorber is only 6.5mm, corresponding to 0.16λmax~0.61λmin. The test results are in good agreement with the simulation results, which proves that the water-based absorber has good performance. It can be applied in the field of electromagnetic(EM) stealth, EM energy harvesting and EM shielding.

scholarly journals Ultrawideband Low-Profile and Miniaturized Spoof Plasmonic Vivaldi Antenna for Base Station

2020 ◽  
Vol 10 (7) ◽  
pp. 2429 ◽  
Author(s):  
Li Hui Dai ◽  
Chong Tan ◽  
Yong Jin Zhou
Keyword(s):  
Radiation Pattern ◽  
Frequency Band ◽  
High Gain ◽  
Base Station ◽  
Ultra Wideband ◽  
Radiation Patterns ◽  
Low Profile ◽  
Simulation Results ◽  
Vivaldi Antenna ◽  
Good Agreement

Stable radiation pattern, high gain, and miniaturization are necessary for the ultra-wideband antennas in the 2G/3G/4G/5G base station applications. Here, an ultrawideband and miniaturized spoof plasmonic antipodal Vivaldi antenna (AVA) is proposed, which is composed of the AVA and the loaded periodic grooves. The designed operating frequency band is from 1.8 GHz to 6 GHz, and the average gain is 7.24 dBi. Furthermore, the measured results show that the radiation patterns of the plasmonic AVA are stable. The measured results are in good agreement with the simulation results.

Design and Simulation Analysis of Vibration Energy Harvesting System Based on ADAMS

2019 ◽  
Author(s):  
Ziheng Zhu ◽  
Lin Xu ◽  
Mohamed A. A. Abdelkareem ◽  
Junyi Zou ◽  
Jia Mi
Keyword(s):  
Energy Harvesting ◽  
Vibration Energy ◽  
Bench Test ◽  
Test Results ◽  
Human Beings ◽  
Vibration Energy Harvesting ◽  
Wide Range ◽  
Harvesting Efficiency ◽  
Simulation Results ◽  
Energy Harvesting Efficiency

Abstract With the recent energy crisis, the new energy harvesting technologies have become one of the hot spots in engineering academic research and industrial applications. By its wide range of application fields, vibration energy harvesting technologies have been gradually developed and utilized in which an efficient and stable harvester technology is one of the recent key problems. In order to improve energy harvesting efficiency and reduce energy loss caused by motor inertial commutation, many mechanical structures or hydraulic structures that convert reciprocating vibration energy into single direction rotation of motor are proposed. Although these methods can improve energy harvesting efficiency, they can have negative effects in some cases, especially in the case of vibration energy harvesting from human beings. This paper proposes a vibration harvesting mechanism with mechanical rectification filter function applied to backpack. The prototype model of the system was established in SolidWorks and imported into ADAMS. Thereafter, dynamic analyses of mechanical rectification filtering characteristics and meshing characteristics of one-way clutch were simulated in ADAMS. Based on ADAMS, parametric design analysis and its influence on the mechanical rectification characteristics were investigated. The simulation results were validated by bench test results. Simulation results is done by ADAMS and the results match well with bench test results.

Ultra-wideband elliptical patch antenna for microwave imaging of wood

2019 ◽  
Vol 11 (9) ◽  
pp. 948-966 ◽  
Author(s):  
Tale Saeidi ◽  
Idris Ismail ◽  
Wong Peng Wen ◽  
Adam R. H. Alhawari
Keyword(s):  
Low Frequency ◽  
Wide Band ◽  
Microwave Imaging ◽  
Ultra Wideband ◽  
Uniform Illumination ◽  
Elliptical Shape ◽  
Measurement Results ◽  
Simulation Results ◽  
Strip Loading ◽  
Good Agreement

AbstractThis paper presents the design of an elliptical shape ultra-wide band antenna for imaging of wood. The antenna is constructed comprising an elliptical shape of patch loaded by a stub to resonate at lower bands, strip loading at the back, and chamfered ground. Despite having miniaturized dimensions of 20 mm × 20 mm, the proposed antenna shows better results compared to recent studies. The simulation results depict a good ultra-wide bandwidth from 2.68 to 16 GHz, and 18.2–20 GHz. Besides, the proposed antenna has two low-frequency bands at 0.89–0.92 and 1.52–1.62 GHz, maximum gain of 5.48 dB, and maximum directivity of 6.9 dBi. The measurement outcomes are performed in air, plywood, and high-density wood and show a good agreement with the simulated results done using electromagnetic simulator CST. In addition to that, the measurement results of S-parameters, transmitted and received signals show a good agreement with the simulated results. Besides, the measured results illustrate a good isolation and uniform illumination among arrays as well as the received signals' shapes do not change in different environments, but only the amplitude. Hence, the proposed antenna seems to be adequate for microwave imaging of wood.

Heat-resistant and photoluminescent indole-based poly(ether sulfone)s

2017 ◽  
Vol 30 (4) ◽  
pp. 475-479 ◽  
Author(s):  
Wenxuan Wei ◽  
Li Yang ◽  
Guanjun Chang
Keyword(s):  
Thermal Stability ◽  
High Performance ◽  
Proton Nuclear Magnetic Resonance ◽  
Resonance Spectroscopy ◽  
Condensation Polymerization ◽  
High Glass Transition Temperature ◽  
Scanning Calorimetry ◽  
Good Thermal Stability ◽  
High Performance Polymers ◽  
Good Agreement

Indole-based poly(ether sulfone)s (PINESs), as novel high-performance polymers, have been obtained by the condensation polymerization of 4-hydroxyindole and hydroquinone with activated difluoro monomers via a catalyst-free nucleophilic substitution reaction. The structures of the polymers are characterized by means of Fourier transform infrared and proton nuclear magnetic resonance spectroscopy, and the results show good agreement with the proposed structures. Differential scanning calorimetry and thermogravimetric analysis measurements exhibit that polymers possess high glass transition temperature ( Tgs > 245°C) and good thermal stability with high decomposition temperatures ( Tds > 440°C). In addition, due to their special structure, PINESs are endowed with significantly strong photonic luminescence in N, N-dimethylformamide.

Fault Tolerant Control of Magnetic Bearings

2001 ◽  
Author(s):  
Uhn Joo Na ◽  
Andrew Provenza ◽  
Alan B. Palazzolo ◽  
Benjamin Choi ◽  
Gerald Montague ◽  
...  
Keyword(s):  
Fault Tolerant ◽  
System Simulation ◽  
Magnetic Bearing ◽  
Rotating Machinery ◽  
Test Results ◽  
Magnetic Forces ◽  
Failure State ◽  
Simulation Results ◽  
Test Verification ◽  
Good Agreement

Abstract This paper provides a new algorithm and test verification for implementing fault-tolerant operation of magnetically suspended, flexible shaft, rotating machinery. The currents to the magnetic bearing are redistributed in a manner so that the bearing actuator preserves the same linearized magnetic forces after some of its coils experience failure. The algorithm that searches a database for the appropriate failure compensation matrix utilizes a Boolean description of the failure state to quickly locate and download its target. The test results are shown to have good agreement with the system simulation results presented.

UWB Bandpass Filter with Ultra-wide Stopband based on Ring Resonator

Frequenz ◽  
2018 ◽  
Vol 72 (5-6) ◽  
pp. 245-252 ◽  
Author(s):  
Maryam Kazemi ◽  
Saeedeh Lotfi ◽  
Hesam Siahkamari ◽  
Mahmood Mohammadpanah
Keyword(s):  
Bandpass Filter ◽  
Ring Resonator ◽  
Ultra Wideband ◽  
Design System ◽  
Filter Performance ◽  
Full Wave ◽  
Measurement Results ◽  
Operational Frequency ◽  
Simulation Results ◽  
Good Agreement

AbstractAn ultra-wideband (UWB) bandpass filter with ultra-wide stopband based on a rectangular ring resonator is presented. The filter is designed for the operational frequency band from 4.10 GHz to 10.80 GHz with an ultra-wide stopband from 11.23 GHz to 40 GHz. The even and odd equivalent circuits are used to achieve a suitable analysis of the proposed filter performance. To verify the design and analysis, the proposed bandpass filter is simulated using full-wave EM simulator Advanced Design System and fabricated on a 20mil thick Rogers_RO4003 substrate with relative permittivity of 3.38 and a loss tangent of 0.0021. The proposed filter behavior is investigated and simulation results are in good agreement with measurement results.

Numerical Modeling of Composite Concrete Walls

2008 ◽  
Author(s):  
Eytan Kochavi ◽  
Yosef Kivity ◽  
Ido Anteby ◽  
Oren Sadot ◽  
Gabi Ben-Dor
Keyword(s):  
University Of California ◽  
Test Results ◽  
Dynamic Tests ◽  
Material Models ◽  
Concrete Walls ◽  
Beer Sheva ◽  
Simulation Results ◽  
The University ◽  
Development Center ◽  
Good Agreement

Dynamic tests of three reinforced concrete samples and six Dynablok samples were performed in the blast simulator facility at the University of California San-Diego (UCSD). The purpose of these tests was to evaluate the performance of a novel protective wall design. These tests were numerically simulated at the Protective Technologies Research and Development Center (PTR&DC) of the Ben-Gurion University (BGU) in Beer-Sheva, Israel. The simulations were carried out using two commercial hydro-codes: LS-Dyna and Dytran. The purpose of these simulations was to calibrate the parameters of the material models available in the above codes. Once calibrated, the simulation results showed good agreement with the test results for largely deflected yet moderately damaged specimens.

STUDY OF PROCESSING AND MECHANICAL BEHAVIOR OF PP/CLAY NANOCOMPOSITES PREPARED BY MELT BLENDING

2012 ◽  
Vol 05 ◽  
pp. 536-544
Author(s):  
SAREH MOSLEH SHIRAZI ◽  
KAMAL JANGHORBAN
Keyword(s):  
Thermal Stability ◽  
Tensile Strength ◽  
Clay Nanocomposites ◽  
Test Results ◽  
Melt Blending ◽  
X Ray Diffraction ◽  
X Ray ◽  
Good Thermal Stability ◽  
Wear Rates ◽  
Tga Analysis

In this research, the melt blending technique was used to prepare various polypropylene (PP) based nanocomposites containing 1,3,5,7 wt% montmorillonite (MMT). A commercial organoclay (denoted K-10) served as the filler for PP matrix and the polypropylene grafted maleic anhydride (PP-g-MA) was used as compatibalizer. The morphology of the nanocomposites was studied by X-ray diffraction (XRD), results of which showed that the nanocomposites are best described as intercalated-exfoliated systems. PP/MMT nanocomposites showed good thermal stability in the TGA analysis. Introducion of ~ 3% MMT in the nanocomposites increased the onset temperature of the degradation by 27.5 °C compared to that of pure PP. Test results showed that PP/clay nanocomposites had an enhanced tensile strength, hardness and decreased wear rates.

A Metal Coordination Crosslinking Novel High Performance Thermoset

2018 ◽  
Vol 913 ◽  
pp. 746-751
Author(s):  
Peng Yang ◽  
Jun Xiao Yang ◽  
Guan Jun Chang
Keyword(s):  
Thermal Stability ◽  
High Performance ◽  
Functional Polymers ◽  
Metal Coordination ◽  
Good Thermal Stability ◽  
H Nmr ◽  
Performance Functional ◽  
Ft Ir ◽  
Thermal Stability Of ◽  
Good Agreement

N-substituted crosslinking polybenzimidazole pyridine sulfone, as novel high performance functional polymers, was prepared by the coordination of N-substituted polybenzimidazole pyridine sulfone (Py-N-PBIS) ligand with varying content of metallic ion (Co2+, Ni2+, Zn2+). The structures of the polymers were characterized by means of FT-IR and 1H NMR spectroscopy, and the results showed a good agreement with the proposed structures. TGA measurements exhibited that the crosslinking polymers possessed good thermal stability with high thermal decomposition temperatures (thermally stable up to 405-510 °C). Additionally, the thermal stability of the coordination polymers was improved constantly with the increasing of the content of Co2+, Ni2+ or Zn2+. The metal coordination crosslinking N-substituted polybenzimidazole pyridine sulfone could be considered as a novel high performance thermoset.

Test and Theory Correlation Study for a Flexible Rotor on Fault-Tolerant Magnetic Bearings

2002 ◽  
Vol 124 (3) ◽  
pp. 359-366 ◽  
Author(s):  
Uhn Joo Na ◽  
Alan B. Palazzolo ◽  
Andrew Provenza
Keyword(s):  
Fault Tolerant ◽  
Correlation Study ◽  
Magnetic Bearing ◽  
Test Results ◽  
Flexible Rotor ◽  
Magnetic Forces ◽  
Failure State ◽  
Simulation Results ◽  
Test Verification ◽  
Good Agreement

This paper provides a new algorithm and test verification for implementing fault-tolerant operation of magnetically suspended, flexible shaft, rotating machinery. The currents to the magnetic bearing are redistributed in a manner so that the bearing actuator preserves the same linearized magnetic forces after some of its coils experience failure. The algorithm that searches a database for the appropriate failure compensation matrix utilizes a Boolean description of the failure state to quickly locate and download its target. The test results are shown to have good agreement with the system simulation results presented.

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