Currently, damage effect of high power microwave 2. HPM characteristics analysis (HPM) on electronic equipments is of increasing interest. HPM can disturb, damage, or destroy many military or civilThere are several parameters, such as frequency, pulse electronic equipments. In this paper, the representative HPM width, pulse rise and fall times, pulse repetition rate, and waveform iS investigated in time and frequency field with pus rieadfl.ie,plerptto ae n waveorm s inestiatedin ime nd fequecy feld power level, which can affect the characteristics of HPM.respectively, and the main characteristics (peak power, rise HPwe vel, w ana affect the canracter cs ofi HM time, power density, etc) are analyzed and listed. HPM HPM waveform analysis in time and frequency field iS generation devices and radiation are also discussed. Coupling presented respectively in this section. energy into electronic devices via front door and back door, as a function of coupling coefficient and the effective area, is 2.1 HPMwaveform modeled. By presenting lots of kinds of coupling modes and Fig. 1 illustrates a representative HPM waveform. As can paths, damage effects are divided into five different classes, be seen from the figure, the HPM waveform has very and damage mechanism of HPM on electronic equipments is fast rising time, slow falling time and short pulse proven in the paper.duration. The frequency band of HPM is narrow, not like

High power electromagnetic pulse (EMP) can easily couple into the inner of targets via lots of slots. To calculate the EMP coupling effects on a cylinder object with openings, the coupling course is simulated using FDTD method in this paper. Gauss pulse and double exponential pulse are selected as the incident pulse source. The coupling EM field strength E inside the object and the current density J on the surface are calculated. Several rules about EMP coupling effects are gotten both in time and frequency domain. The results can help us to understand the damage effects of high power EMP.

The cables in the inner of equipments will also be damaged by high power EMP, because the electromagnetic energy can couple into the inner structure through slots in the shell of equipments. The electromagnetic effects on the thin line in a cubic cavity with a rectangle slot are simulated using thin line FDTD algorithm. The little slot is divided into many thin grids, and the transitional area is divided using sub-gridding technique. The influence of different length, different directions and different location in the cavity of the thin line on electromagnetic effects is studied. Some useful results are gotten.

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Abstract-Transient electromagnetic pulse (EMP) can easily couple into equipments through small apertures in its shells. To study the coupling effects of transient Gauss pulse to a cubic cavity with openings, coupling course is simulated using sub-gridding finite difference in time domain (FDTD) algorithm in this paper. A new grid partition approach is provided to simulate each kind of apertures with complex shapes. With this approach, the whole calculation space is modeled, and six kinds of aperture with different shapes are simulated. Coupling course is simulate in the whole time domain using sub-gridding FDTD approach. Selecting apertures with dimension of several millimeters to research, coupled electric field waveform, power density and coupling coefficient are calculated. The affect on coupling effects by varied incident angle and varied pulse width are also analyzed. The main conclusion includes interior resonance phenomenon, increase effect around rectangle aperture and several distributing rules of coupled electric field in the cavity. The correctness of these results is validated by comparing with other scholars' results. These numerical results can help us to understand coupling mechanism of the transient Gauss pulse.