Effects of Aperture Amount and Offset on Couplings of Strong Electromagnetic Pulse

2011 ◽  
Vol 130-134 ◽  
pp. 1387-1390
Author(s):  
Xin Ping Zhu ◽  
Bing Cao ◽  
Cheng Long Liu
Keyword(s):  
Field Strength ◽  
Electromagnetic Pulse ◽  
Coupling Effect ◽  
Fdtd Method ◽  
Shielding Effectiveness ◽  
Actual Structure ◽  
Aperture Coupling ◽  
Coupling Mode ◽  
Aperture Arrays ◽  
Difference Time

Aperture coupling is a main coupling mode through which strong electromagnetic pulse can disturb and even damage electronic equipments. The amount, offset and mixed shape of aperture arrays can affect the coupling effect, which is analyzed using finite-difference time-domain (FDTD) method. The field strength coupled increases with the decrease of the slot amount when the total area of aperture is unchanged. The shielding effectiveness is the smallest when the electromagnetic pulse reaches the resonant frequency, which is only affected by the actual structure size of the shielding cavity. Comparing to two direction offset, the single achieved much larger field strength, which is symmetrical about offset center. The coupled field strength is the smallest when the shape of aperture arrays contains round and rectangular.

The Lightning Electromagnetic Pulse Coupling Effect Inside the Shielding Enclosure With Penetrating Wire

Frequenz ◽  
2017 ◽  
Vol 71 (11-12) ◽  
Author(s):  
Xue Jiao ◽  
Bo Yang
Keyword(s):  
Electromagnetic Pulse ◽  
Coupling Effect ◽  
Fdtd Method ◽  
Current Source ◽  
Low Frequency ◽  
Frequency Component ◽  
Lightning Current ◽  
Proper Size ◽  
Practical Engineering ◽  
Difference Time

AbstractTo study the lightning electromagnetic pulse (LEMP) coupling and protection problems of shielding enclosure with penetrating wire, we adopt the model with proper size which is close to the practical engineering and the two-step finite-difference time-domain (FDTD) method is used for calculation in this paper. It is shown that the coupling voltage on the circuit lead inside the enclosure increases about 34 dB, when add 1.0 m long penetrating wire at the aperture, comparing with the case without penetrating wire. Meanwhile, the waveform, has the same wave outline as the lightning current source, shows that the penetrating wire brings a large number of low frequency component into the enclosure. The coupling effect in the enclosure will reduce greatly when penetrating wire has electrical connection with the enclosure at the aperture and the coupling voltage increase only about 12 dB than the case without penetrating wire. Moreover, the results show that though the waveguide pipe can reduce the coupling effect brought by the penetrating wire, the exposing part of penetrating wire can increase the coupling when the penetrating wire outside the enclosure is longer than the waveguide pipe and the longer the exposing part is, the stronger the coupling is.

Damage Efficiency Research of PCB Components under Strong Electromagnetic Pulse

2011 ◽  
Vol 130-134 ◽  
pp. 1383-1386 ◽  
Author(s):  
Fei Xie ◽  
Bing Cao ◽  
Cheng Long Liu
Keyword(s):  
Finite Difference ◽  
Field Strength ◽  
Power Density ◽  
Time Domain ◽  
Rise Time ◽  
Finite Difference Time Domain ◽  
Electromagnetic Pulse ◽  
Magnetic Pulse ◽  
Electro Magnetic ◽  
Difference Time

To study damage effectiveness of strong electro-magnetic pulse to components of equipments, the power density in area of MOS circuit, diodes and transistor of a computer is simulated, using the method of the finite-difference time-domain (FDTD). Coupling laws in different areas are achieved, and then judging the damage efficiency of components. Electromagnetic pulse reflects constantly in computer box, causing power density appears oscillations. Energy gradually declines to zero, for it radiates outward from slots. Field concentration around PCB board results in dissociation of field strength, and slows down the attenuation of energy. Finally, formula of power density at random field strength and rise time is also obtained.

Simulation Study on Coupling Effect under HEMP of Shielding Control Box

2014 ◽  
Vol 551 ◽  
pp. 309-314
Author(s):  
Long Dou ◽  
Bin Chen ◽  
Hai Lin Chen ◽  
Fei Guo
Keyword(s):  
Complex System ◽  
Field Distribution ◽  
Simulation Study ◽  
Electromagnetic Pulse ◽  
Coupling Effect ◽  
Calculation Model ◽  
Shielding Effectiveness ◽  
Coupling Field ◽  
Depth Direction ◽  
Energy Pulse

The coupling effect under HEMP calculation model of the shielding control box is established with the CST software. The shielding effectiveness of the shielding control box with different incidence directions of HEMP were studied on, and the field distribution of the shielding control box was analyzed. The results show that incidence direction of HEMP in the depth direction of the gap and perpendicular to the long side of the gap can provide the worst electromagnetic pulse protection of shielding control box. The coupling field of the complex system box has resonant characters. The gap filled with conductive rubber can effectively reduce the coupling of electromagnetic energy pulse.

Analysis of high power electromagnetic pulse coupling effect of photovoltaic panel by using FDTD method

2021 ◽  
Author(s):  
Hai-Sheng Song ◽  
Ya-Tong Hou ◽  
Shan-Luo ◽  
Zheng-Yu Huang ◽  
Shuai Zhu ◽  
...  
Keyword(s):  
High Power ◽  
Electromagnetic Pulse ◽  
Coupling Effect ◽  
Fdtd Method ◽  
Photovoltaic Panel

scholarly journals Optically transparent and very thin structure against electromagnetic pulse (EMP) using metal mesh and saltwater for shielding windows

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Duy Tung Phan ◽  
Chang Won Jung
Keyword(s):  
Electromagnetic Pulse ◽  
Low Cost ◽  
High Energy ◽  
Metal Plate ◽  
Optical Transparency ◽  
Shielding Effectiveness ◽  
Concrete Wall ◽  
Metal Mesh ◽  
Wide Range ◽  
Optically Transparent

AbstractAn electromagnetic pulse (EMP) with high energy can damage electronic equipment instantly within a wide range of thousands of kilometers. Generally, a metal plate placed inside a thick concrete wall is used against an EMP, but it is not suitable for an EMP shielding window, which requires not only strong shielding effectiveness (SE) but also optical transparency (OT). In this paper, we propose a very thin and optically transparent structure with excellent SE for EMP shielding window application. The proposed structure consists of a saltwater layer held between two glass substrates and two metal mesh layers on the outside of the glass, with a total thickness of less than 1.5 cm. The SE and OT of the structure are above 80 dB and 45%, respectively, which not only meet the requirement of EMP shielding for military purposes but also retain the procedure of good observation. Moreover, the OT of the structure can be significantly improved using only one metal mesh film (MMF) layer, while the SE is still maintained high to satisfy the required SE for home applicants. With the major advantages of low cost, optical transparency, strong SE, and flexible performance, the proposed structure can be considered a good solution for transparent EMP shielding windows.

scholarly journals Designing the Hotspots Distribution by Anisotropic Growth

Molecules ◽  
2021 ◽  
Vol 26 (1) ◽  
pp. 187
Author(s):  
Tianshun Li ◽  
Renxian Gao ◽  
Xiaolong Zhang ◽  
Yongjun Zhang
Keyword(s):  
Au Nanoparticles ◽  
Fdtd Method ◽  
Polarization Dependence ◽  
Noble Metal Nanoparticles ◽  
Oblique Angle Deposition ◽  
Matlab Simulation ◽  
Different Shapes ◽  
Plasma Enhancement ◽  
Difference Time ◽  
Good Agreement

Changing the morphology of noble metal nanoparticles and polarization dependence of nanoparticles with different morphologies is an important part of further research on surface plasma enhancement. Therefore, we used the method based on Matlab simulation to provide a simple and effective method for preparing the morphologies of Au nanoparticles with different morphologies, and prepared the structure of Au nanoparticles with good uniformity and different morphologies by oblique angle deposition (OAD) technology. The change of the surface morphology of nanoparticles from spherical to square to diamond can be effectively controlled by changing the deposition angle. The finite difference time domain (FDTD) method was used to simulate the electromagnetic fields of Au nanoparticles with different morphologies to explore the polarization dependence of nanoparticles with different shapes, which was in good agreement with Raman spectrum.

Trapping of Nano-Particles Using a Near-Field Optical Fiber Probe

2012 ◽  
Vol 516 ◽  
pp. 90-95
Author(s):  
Bing Hui Liu ◽  
Li Jun Yang ◽  
Yang Wang
Keyword(s):  
Near Field ◽  
Fdtd Method ◽  
Laser Wavelength ◽  
Nano Particles ◽  
Minimum Size ◽  
Fiber Probe ◽  
Circular Shape ◽  
Optical Fiber Probe ◽  
Fibre Probe ◽  
Difference Time

By employing a generalization of the conservation law for momentum using the finite difference time domain (FDTD) method, the feasibility of using a near-field optical fibre probe to create near-field optical trapping is investigated. Numerical results indicate that the scheme is able to trap nanoparticles with diameters of tens of nanometres in a circular shape with lower laser intensity. Using the built system with a tapered metal-coated fibre probe, 120 nm polystyrene particles are trapped in a multi-circular shape with a minimum size of 400 nm. They are at a resolution of λ/7 (λ: laser wavelength) and d (d: tip diameter of fiber probe), respectively.

Investigation of Contact Conditions During Stamping of a Thin Plate

2020 ◽  
Author(s):  
Harshal Y. Shahare ◽  
Rohan Rajput ◽  
Puneet Tandon
Keyword(s):  
Wave Propagation ◽  
Material Properties ◽  
High Speed ◽  
Fdtd Method ◽  
Propagation Model ◽  
Transmitted Wave ◽  
Two Dimensional ◽  
Contact Conditions ◽  
Simulation Based ◽  
Difference Time

Abstract Stamping is one of the most used manufacturing processes, where real-time monitoring is quite difficult due to high speed of the mechanical press, which leads to deterioration of the accuracy of the products In the present work, a method is developed to model elastic waves propagation in solids to measure contact conditions between die and workpiece during stamping. A two-dimensional model is developed that reduces the wave propagation equations to two-dimensional equations. To simulate the wave propagation inside the die-workpiece model, the finite difference time domain (FDTD) method and modified Yee algorithm has been employed. The numerical stability of the wave propagation model is achieved through courant stability condition, i.e., Courant-Friedrichs-Lewy (CFL) number. Two cases, i.e., flat die-workpiece interface and inclined die-workpiece interface, are investigated in the present work. The elastic wave propagation is simulated with a two-dimension (2D) model of the die and workpiece using reflecting boundary conditions for different material properties. The experimental and simulation-based results of reflected and transmitted wave characteristics are compared for different materials in terms of reflected and transmitted wave height ratio and material properties such as acoustic impedance. It is found that the numerical simulation results are in good agreement with the experimental results.

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