Analysis of EMP coupling process and effectiveness to the cavity with capture in frequency-domain

The effect of electromagnetic pulse coupled to the cavity with capture is studied using finite difference time-domain method. The calculating results in time-domain are transformed to frequency domain. Then the results are analyzed in frequency domain using analytical results. The coupling fields big or small in time domain change in frequency domain. The resonance modes in the cavities excited by the different EMPs are determined only by the physical dimensions. The fields passing through the hole can be taken as the guided waves. The ratios of the magnitudes in frequency-domain located at the hole and the certain points in the cavity are identical and almost do not vary with the incident EMPs. (authors)