Theoretical expressions for predicting shielding effectiveness of thin conducting films for the plane shield case

Thin conducting films or metallic films can be used to improve the performance of the plastic enclosures widely used by modern industry to produce economic container designs for electrical equipment. The transmission coefficients of thin metallic films in both the frequency and time domains are developed. The features of the two transmission coefficients in the time domain are pointed out. In addition, the transmission coefficient in the frequency domain can be directly used to predict shielding effectiveness, whereas the convolution of the arbitrarily incident waveform and the transmission coefficient in the time domain is introduced to analyze the property of the decay of the transmitted field.