Yi Yun

Simulation of EMP coupling to thin lines using three-dimensional ADI-FDTD method

In this paper, the EMP coupling to thin lines is simulated using three-dimensional ADI-FDTD method. To simplify the modification of update equation near TF/SF connective boundary, the plane wave is introduced by defining a set of equivalent currents on a closed Huygens surface. The numerical results indicate that under the illumination of EMP wave, the peak value of induced current is not linear with the length of line. When the length of line reaches certain value the induced current can be found have a maximum peak value. With the electric field intensity of 50 kVm-1, the peak value of induced current can come to several ten amperes

The penetrating of EMP fields into a metal shielding enclosure by a slot

The shielding effectiveness to different sized slots in a shielding enclosure is calculated using the FDTD method. It is demonstrated that the resonance of a shielding enclosures cavities and slots greatly influences a screened rooms shielding effectiveness. Fast time-varying EMP couples more easily in a shielding cavity with slots.

Implementation of the Split-Field Method for FSS Structures

A method for implementing the periodic boundary condition(PBC) in the finite-difference time-domain algorithm(FDTD) is presented. By using the split-field method, a set of auxiliary elements are introduced to realize the discretization of the Floquet-transformed Maxwells equations with oblique incidence. The UPML equations for the split-field FDTD are also described. The method is applied to a doubly periodic infinite frequency selected surface (FSS) and numerical results are compared to authoritative solutions, demonstrating its validity and utility.

An Unconditionally Stable Scheme using R-FDTD for the Scattering Problems

An unconditionally stable numerical method combined with R-FDTD for the scattering problems is proposed. The marching-on in time method as in the FDTD scheme is replaced by a marching-on in order method based on weighted Laguerre polynomials. The divergence relationship is also used in the proposed method, which leads to a more memory efficient formulation. To verify the accuracy and the efficiency of the proposed method, we compare the results of the conventional FDTD method with the proposed method

Study on the HEMP induced current in the two-wire line with the metal shielded bushing

Lines into and out of a shielding box, such as power supply line and communication line are important ways by which coupling of electromagnetic pulsed energy interferes with and harms the circuit. In this paper, induced current in the two-wire line enclosed by a metal shielded bushing with one end exposed to HEMP is calculated by using the 3D FDTD method. The two-wire line is near the ground and the metal shielded bushing is directly grounded at both ends. The result is reasonable compared to the experimental data.