Analyzing of the Near-Field Shielding Effectiveness of the Cylindrical Cavity with Apertures

2013 ◽  
Vol 462-463 ◽  
pp. 573-577
Author(s):  
Jie Qing Fan ◽  
Jian Hong Hao ◽  
Zi Xian Song ◽  
Xue Fen Liu
Keyword(s):  
Cylindrical Cavity ◽  
Near Field ◽  
Equivalent Circuit Model ◽  
Shielding Effectiveness ◽  
Half Wavelength ◽  
Transmission Line Method ◽  
Analytical Formulas ◽  
Simulation Results ◽  
Electromagnetic Disturbances ◽  
Good Agreement

The equivalent circuit model of shielding effectiveness of the cylindrical cavity with apertures against the near-field waves of electric dipole is established. The analytical formulas for approximately calculating the shielding effectiveness are given by the adjusted transmission line method. It is shown that the near-field shielding effectiveness of a cylindrical cavity with apertures is far inferior to that of far-field. The near-filed SE of the cylindrical cavity increases with the distance between the diploe and the apertured cavity, but when the distance is greater than a half wavelength of the electromagnetic disturbances, the SE tends to be saturated. In the cavity, the electric SE increased with the distance of observation points to the apertures. Results of the adjusted TLM are in good agreement with the CST simulation results.

Evaluation of PCB Shielding Characteristic in Near Field

2017 ◽  
Vol 5 (3) ◽  
pp. 542
Author(s):  
Yih Jian Chuah ◽  
Mohd Tafir Mustaffa
Keyword(s):  
Electromagnetic Interference ◽  
High Frequency ◽  
Near Field ◽  
Electronic Devices ◽  
The Other ◽  
Shielding Effectiveness ◽  
Electronic Industry ◽  
Common Solution ◽  
The Common ◽  
Simulation Results

Wireless electronic devices nowadays always operate in high frequency while having small and compact form factor which led to electromagnetic interference among traces and components. PCB shielding is the common solution applied in electronic industry to mitigate electromagnetic interference. In this paper, PCB shielding characteristics such as shield’s thickness, height, and ground via spacing in PCB boards were evaluated in near field. Test boards with various ground via spacing were fabricated and evaluated by using 3D Electromagnetic scanner. On the other hand, shields with various thickness and height were modeled and evaluated through simulation. Results suggested that shielding effectiveness could be improved by having greater shield’s height with smaller ground via spacing in shielding ground tracks. Shielding effectiveness can be improved by 1 dB with every step of 0.5 mm increase in shield’s height. Besides that, approximately 0.5 dB improvement in shielding effectiveness with every step of 1 mm decrease in ground via spacing. Furthermore, greater shield’s thickness can contribute better shielding effectiveness for operating frequency below 300 MHz.

scholarly journals Miniaturized Dielectric Disc Loaded Monopole Antenna

2021 ◽  
Author(s):  
Khan Masood Parvez ◽  
SK. Moinul Haque ◽  
Laxmikant Minz
Keyword(s):  
Resonant Frequency ◽  
Dielectric Material ◽  
Equivalent Circuit Model ◽  
Monopole Antenna ◽  
Radiation Characteristics ◽  
Antenna Length ◽  
Capacitive Effect ◽  
Simulation Results ◽  
Gps System ◽  
Good Agreement

This paper deals with miniaturization technique based on frequency reduction using top loaded dielectric discs. In contrast to a simple monopole, the resonant frequency of monopole loaded with two dielectric discs changes from 1.98 to 1.29 GHz, resulting 34.84% reduction in resonant frequency keeping the antenna length (36.00 mm) unaltered. It is well-known fact that dielectric material can trap the energy to be delivered from source to antenna and as a result, it is unable to radiate efficiently. Then any approach to use the dielectric material for miniaturization process must, therefore, antenna coupled in such a way that it can radiate efficiently. The dielectric disc on top of monopole creates an inductive situation in a similar way to oppositely directed wire loop compensate the capacitive effect present at monopole causes the reduction in resonant frequency. This concept is implemented without sacrificing any desired features like bandwidth, radiation characteristics and efficiency (more than 98%) and analyzed with an equivalent circuit model. Experimental results illustrate good agreement with simulation results. This monopole antenna in car can be designed for GPS system, car to car communication, GSM or CDMA operation.

scholarly journals Mobile Phones as Sources of Electromagnetic Interference

2007 ◽  
Vol 3 (1) ◽  
pp. 26
Author(s):  
Jacek Skrzypczynski ◽  
Vesna Roje ◽  
Kurt Lamedschwandner ◽  
Sinisa Antonijevic ◽  
Cecil Stefan
Keyword(s):  
Mobile Phones ◽  
Electromagnetic Interference ◽  
Near Field ◽  
Metal Plate ◽  
Field Coupling ◽  
Computer Codes ◽  
Simulation Results ◽  
The Wire ◽  
Methods Of Moments ◽  
Good Agreement

The paper deals with a problem of interference as a result of the mobile phone coupling into the cabling of a complexsystem. The phenomenon has been simplified to a problem of near field coupling between a radiating antenna and a wire placed near a metal plate in an open area. Numerical simulations based on Methods of Moments have been performed for various lengths of the wire, for different distance between the wire and the plate, and for three polarizations of the antenna. The results for the voltage induced at the cable termination have been obtained while the antenna has been moving along the full length of the wire. Good agreement of the simulation results obtained bydifferent approaches and different computer codes has beenfound. The simulation results have been checked experimentally.

scholarly journals Design of Low-Profile Frequency-Selective Rasorbers Based on Three-Legged Loaded Element

2020 ◽  
Vol 2020 ◽  
pp. 1-8 ◽  
Author(s):  
Yu Qiang ◽  
Dongfang Zhou ◽  
Qikun Liu ◽  
Zhenning Yao
Keyword(s):  
Layer Structure ◽  
Equivalent Circuit Model ◽  
Bottom Layer ◽  
Frequency Selective Surface ◽  
Structure Model ◽  
Unit Cell Size ◽  
Low Profile ◽  
Simulation Results ◽  
Frequency Selective ◽  
Good Agreement

A novel low-profile dual-polarization frequency-selective rasorber (FSR) with a transmissive window in the absorption band is proposed in this paper. Based on the equivalent circuit model (ECM), the principles of the impedance design are theoretically derived. Then, a two-layer structure model is constructed. The top layer is composed of a lossy three-legged loaded element (TLLE), and the bottom layer is composed of a square ring bandpass frequency-selective surface (FSS). Furthermore, the strips are folded to reduce the unit cell size to stabilize the angular response. The maximum stable response angle increases from 20 to 40° due to the miniaturized design under both TE and TM polarization. The experimental results of the prototype are in good agreement with the simulation results, which validates the rationality of our design.

Direction of Arrival Estimation Under Near-Field Interference Using Matrix Filter

2015 ◽  
Vol 23 (04) ◽  
pp. 1540007 ◽  
Author(s):  
Guolong Liang ◽  
Wenbin Zhao ◽  
Zhan Fan
Keyword(s):  
Near Field ◽  
Direction Of Arrival ◽  
Doa Estimation ◽  
Direction Of Arrival Estimation ◽  
Far Field ◽  
Data Simulation ◽  
Estimation Algorithms ◽  
Simulation Results

Direction of arrival (DOA) estimation is of great interest due to its wide applications in sonar, radar and many other areas. However, the near-field interference is always presented in the received data, which may result in degradation of DOA estimation. An approach which can suppress the near-field interference and preserve the far-field signal desired by using a spatial matrix filter is proposed in this paper and some typical DOA estimation algorithms are adjusted to match the filtered data. Simulation results show that the approach can improve capability of DOA estimation under near-field inference efficiently.

scholarly journals Measuring Hydrometeors Using a Precipitation Microphysical Characteristics Sensor: Sampling Effect of Different Bin Sizes on Drop Size Distribution Parameters

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Xichuan Liu ◽  
Taichang Gao ◽  
Yuntao Hu ◽  
Xiaojian Shu
Keyword(s):  
Drop Size ◽  
Rain Rate ◽  
Monte Carlo Model ◽  
Rain Gauge ◽  
Sampling Schemes ◽  
Distribution Parameters ◽  
Optimum Sampling ◽  
Simulation Results ◽  
The Impact ◽  
Good Agreement

In order to improve the measurement of precipitation microphysical characteristics sensor (PMCS), the sampling process of raindrops by PMCS based on a particle-by-particle Monte-Carlo model was simulated to discuss the effect of different bin sizes on DSD measurement, and the optimum sampling bin sizes for PMCS were proposed based on the simulation results. The simulation results of five sampling schemes of bin sizes in four rain-rate categories show that the raw capture DSD has a significant fluctuation variation influenced by the capture probability, whereas the appropriate sampling bin size and width can reduce the impact of variation of raindrop number on DSD shape. A field measurement of a PMCS, an OTT PARSIVEL disdrometer, and a tipping bucket rain Gauge shows that the rain-rate and rainfall accumulations have good consistencies between PMCS, OTT, and Gauge; the DSD obtained by PMCS and OTT has a good agreement; the probability of N0, μ, and Λ shows that there is a good agreement between the Gamma parameters of PMCS and OTT; the fitted μ-Λ and Z-R relationship measured by PMCS is close to that measured by OTT, which validates the performance of PMCS on rain-rate, rainfall accumulation, and DSD related parameters.

scholarly journals Simulation and Experimental Study on Wear of U-Shaped Rings of Power Connection Fittings under Strong Wind Environment

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 735
Author(s):  
Songchen Wang ◽  
Xianchen Yang ◽  
Xinmei Li ◽  
Cheng Chai ◽  
Gen Wang ◽  
...  
Keyword(s):  
Abrasive Wear ◽  
Adhesive Wear ◽  
Surface Hardness ◽  
Wear Depth ◽  
Strong Wind ◽  
Wear Model ◽  
Wind Environment ◽  
Simulation Results ◽  
Oxidation Wear ◽  
Good Agreement

The objective of this study was to investigate the wear characteristics of the U-shaped rings of power connection fittings, and to construct a wear failure prediction model of U-shaped rings in strong wind environments. First, the wear evolution and failure mechanism of U-shaped rings with different wear loads were studied by using a swinging wear tester. Then, based on the Archard wear model, the U-shaped ring wear was dynamically simulated in ABAQUS, via the Umeshmotion subroutine. The results indicated that the wear load has an important effect on the wear of the U-shaped ring. As the wear load increases, the surface hardness decreases, while plastic deformation layers increase. Furthermore, the wear mechanism transforms from adhesive wear, slight abrasive wear, and slight oxidation wear, to serious adhesive wear, abrasive wear, and oxidation wear with the increase of wear load. As plastic flow progresses, the dislocation density in ferrite increases, leading to dislocation plugs and cementite fractures. The simulation results of wear depth were in good agreement with the test value of, with an error of 1.56%.

TCAD Study of the Raised SiGe Source/Drain in 40nm PMOS

2015 ◽  
Vol 645-646 ◽  
pp. 70-74 ◽  
Author(s):  
Min Zhong ◽  
Yu Hang Zhao ◽  
Shou Mian Chen ◽  
Ming Li ◽  
Shao Hai Zeng ◽  
...  
Keyword(s):  
Computer Aided Design ◽  
Critical Role ◽  
Sige Layer ◽  
Strain Engineering ◽  
Effect Transistor ◽  
Simulation Results ◽  
Aided Design ◽  
The Relationship ◽  
Growth Experiments ◽  
Good Agreement

An embedded SiGe layer was applied in the source/drain areas (S/D) of a field-effect transistor to boost the performance in the p channels. Raised SiGe S/D plays a critical role in strain engineering. In this study, the relationship between the SiGe overfilling and the enhancement of channel stress was investigated. Systematic technology computer aided design (TCAD) simulations of the SiGe overfill height in a 40 nm PMOS were performed. The simulation results indicate that a moderate SiGe overfilling induces the highest stress in the channel. Corresponding epitaxial growth experiments were done and the obtained experimental data was in good agreement with the simulation results. The effect of the SiGe overfilling is briefly discussed. The results and conclusions presented within this paper might serve as useful references for the optimization of the embedded SiGe stressor for 40 nm logic technology node and beyond.

Numerical Simulation on Thixo-Forging of Magnesium Matrix Composite

2011 ◽  
Vol 189-193 ◽  
pp. 2535-2538 ◽  
Author(s):  
Hong Yan ◽  
Wen Xian Huang
Keyword(s):  
Numerical Simulation ◽  
Matrix Composite ◽  
Metal Flow ◽  
Magnesium Matrix Composite ◽  
Magnesium Matrix ◽  
Simulation Based ◽  
Prior Literature ◽  
Simulation Results ◽  
Computer Numerical Simulation ◽  
Good Agreement

The thixo-forging of magnesium matrix composite was analyzed with computer numerical simulation based on rigid viscoplastic finite element method. The constitutive model of SiCp/AZ61 composite was established in our prior literature. Behavior of metal flow and temperature field were obtained. The differences between traditional forging and thixo-forging processes were analyzed. Results indicated that thixo-forging was better in filling cavity than forging. Simulation results were good agreement with experimental ones.

The penetration and ricochet of ogive-nosed rigid projectiles obliquely impacting metallic targets

2021 ◽  
pp. 204141962110377
Author(s):  
Yaniv Vayig ◽  
Zvi Rosenberg
Keyword(s):  
Experimental Data ◽  
Numerical Simulations ◽  
Dynamic Pressure ◽  
Oblique Impacts ◽  
Simulation Results ◽  
The Impact ◽  
Penetration Depths ◽  
Resistance To Penetration ◽  
Good Agreement

A large number of 3D numerical simulations were performed in order to follow the trajectory changes of rigid CRH3 ogive-nosed projectiles, impacting semi-infinite metallic targets at various obliquities. These trajectory changes are shown to be related to the threshold ricochet angles of the projectile/target pairs. These threshold angles are the impact obliquities where the projectiles end up moving in a path parallel to the target’s face. They were found to depend on a non-dimensional entity which is equal to the ratio between the target’s resistance to penetration and the dynamic pressure exerted by the projectile upon impact. Good agreement was obtained by comparing simulation results for these trajectory changes with experimental data from several published works. In addition, numerically-based relations were derived for the penetration depths of these ogive-nosed projectiles at oblique impacts, which are shown to agree with the simulation results.

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