Estimate of shielding efficiency for double layer enclosure with apertures array

A relatively simple Transmission Line Model (TLM) has been developed to research the coupling efficiency (CE) characteristic of electromagnetic pulse and the shielding efficiency (SE) of double layer shielding rectangular enclosure with apertures. The electric coupling efficiency (CE) of single layer with aperture is compared with that of double layer with apertures array. The simulation results show that: SE can be improved greatly with double layer shielding and it is worse on the resonance frequency of enclosure modes. On the condition of enclosure resonance, SE drops significantly in the centre of inner enclosure. The finite-difference time-domain (FDTD) result is used to compare the results of TLM. Further discuss shows that the coupling efficiency decreases by the increasing number of apertures when the total area of apertures is kept the same.