Evaluation of the EMP shielding effectiveness for the thin metallic shells

It is essential for many EMC problems to evaluate the transient shielding effectiveness of thin metallic shells. A fast time domain approach is presented to calculate the transient shielding effectiveness of the thin metallic shells excited by an arbitrary waveform electromagnetic pulse. The frequency domain transfer function of the thin metallic shell is fitted into the rational function by the vector fitting method, and the pulse response can be expressed by a sum of decay exponentials in the time domain by the inverse Laplace transformation. The transient shielding effectiveness excited by an arbitrary waveform can be obtained easily based on the recursive convolution formulation. The advantage of the proposed method lies in two aspects. It is a time domain algorithm without needing the time-consuming FFT approach, and the scheme of recursive convolution can improve the calculation efficiency dramatically. The proposed approach is validated by some numerical examples.