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To reduce the electromagnetic radiation, we set a metal layer to surround lightning rod for shielding. Then we use the finite-difference time-domain (FDTD) method to analyze the field distribution laws of this situation. Moreover, we also calculate the corresponding field distribution without metal layer for comparison. It is shown that the metal layer affects the electromagnetic field distribution...
In order to obtain the orientation of the lightning discharging channel, this paper designs and makes two types of LEMP three dimensional magnetic field directional device, which consist of three orthogonal loop antennas. The antennas are of two layer's structure with outside-inside conductors and same area. The experiment results prove that the devices performance well and the “site errors” are in...
In this paper, we construct a MRTD model in Cylindrical Grids with perfect matched layer (PML), and apply the MRTD method to calculate electromagnetic fields of lightning return stroke. According to the MRTD framework, scaling function of Dubieties wavelet is choosed for fields expansion and discrimination, special consideration are also given for absorption boundary condition. Numerical simulation...
Plasma is conductor and dispersive medium. It can shield electromagnetic field. Plasma has a remarkable feature: its medium parameters are changeable with frequency. In this paper, the Frequency-Dependent Finite-Difference Time-Domain ((FD)2TD) method is used to model electromagnetic reflection and transmission. First efficiency of SO-FDTD is verified. Then electromagnetic reflection and transmission...
Most of the measurements of nature lightning current time-domain waveforms were taken at the tall towers and tall buildings. In order to study the influence of tall towers on lightning current measurement, the transmission line (TL) model of the lightning return stroke was applied to calculate the lightning current at different positions of the tower. This paper also analyzed the factors which influence...
The shielding effectiveness (SE) test is usually implemented in the bounded-wave simulator. However, numerical simulating the SE of a shielding enclosure is mostly modeled with plane wave incidence. In this paper we present the parallel FDTD method to analyze the SE of a shielding enclosure in bounded-wave simulator. An improved formalism for thin slot is adopted. The result shows that the result...
In order to analyze the influence of grounding conditions on the shielding effectiveness (SE) of shielded room, numerical simulation is done by applying parallel Finite-Difference Time-Domain (FDTD) method on the coupling problems between shielded room and lightning electromagnetic pulse (LEMP) environments. Inner coupled electromagnetic (EM) fields are calculated when the shielded room is with different...
When the aircraft suffers lightning, great lightning current will produced in the fuselage. It will imperil aero safely badly. In the paper, electromagnetic simulation software CST MS studio is used to simulate the situation that the plane attacked by lightning. And analysis the changes of field inside and outside the aircraft. The analytical results will provide reference for practical engineering...
Aperture coupling is the primary way that electromagnetic interference energy into the metal chamber, which would damage the electronic equipment. Articles use FEKO electromagnetic simulation software to analysis the aperture coupling electromagnetic field inside the metal chamber with equal-area different shape (square, circular, rectangular) and the different number apertures. Analysis results showed...
New finite-difference time-domain (FDTD) update equations for long thin wire are presented. The axis of long thin wire is assumed to be diagonal to the Yee cell faces. Derived using the contour-path method, the new equations properly models the singular field near the long thin wire. A dramatic improvement in computed accuracy was observed when a stripline with long thin wire diagonal to the Yee cell...
This paper introduces the structure of gigahertz TEM cell (GTEM cell). And the Finite-Difference Time-Domain (FDTD) method is used to model electromagnetic field of effective work space of GTEM cell accurately. The effect of meauring system put at the effective work space is also analyzed. This work will offer theory direction of electromagnetic field distribution of effective work space of GTEM cell.
When electric field is measured in the bounded-wave EMP simulator experiment, one kind of optical fiber measurement system is often used. At the same time, the effect of optical transmitter on electromagnetic wave distribution is often concerned. In this paper, we assume that the optical transmitter is placed on the working region of the bounded-wave EMP simulator and the Finite-Difference Time-Domain...
The radiative device made of metal sheet is the key part of an EMP simulator with absorbing stuff. In order to extend the effective work space, the radiative device is designed optimised. And the finite-difference time-domain (FDTD) method is used to model electromagnetic field of effective work space of the EMP simulator accurately. From the numerical result, we can see that the optimised radiative...
The body of revolution finite-difference time-domain method for dispersive media is presented which reduce a three-dimensional problem to a two-dimensional one, resulting in an efficient saving of CPU running time and memory requirement. To validate the accuracy and efficiency of the proposed method, we apply it to analyze the scattering from several dispersive bodies of revolution. Compared the result...
A design is proposed for optic fiber system which is used for transient signal transmission, adopting OPA and FET as the input device of optical transmitter separately. The system receives and handle difference divide signal inputted. Through network analyzer, frequency respond of optic fiber transmission system is measured when two kinds of different input terminuses circuit are adopted. When square...
In this paper, we assume that the bounded-wave simulator is placed on the ground in the experiment. And the finite-difference time-domain (FDTD) method is used to model electromagnetic field at working region. From the numerical result, we can see that the ground has great effect on the electromagnetic wave.
Source charge model is reviewed and is used to analyze electric field changes caused by eight directions of lightning streamers. Moreover, an improved piecewise-linear source charge model combined with the three-dimensional radiation source mapping results to interpret electric field changes on the ground is proposed. This model is applied to simulating E-field waveform and calculating electric parameters...
The predigested physical model is set up in this paper according to the geometry shape of the earthing electrode, and the finite-difference time-domain (FDTD) method is used to get the transient grounding resistance (TGR) waveform of the earthing electrode, based on the experimental method. It is showed that the calculation results and the experimental results match well.
In this paper, an EMP simulator with absorbing stuff is designed. Firstly, the EMP simulator is analyzed according to the circuit. Secondly, the Finite-Difference Time-Domain (FDTD) method is used to model electromagnetic field of effective work space of the EMP simulator accurately. This work will offer theory direction of simulatorpsilas optimized design.
In this paper, a bounded-wave EMP simulator is introduced. The finite-difference time-domain (FDTD) method is used to model electromagnetic field at working region produced by the bounded-wave EMP simulator accurately. And this numerical analysis method is feasible from the compare of numerical result with experiment result.
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