On the penetration of the longitudinal component of EM fields into metals

The penetration of an EM wave with the frequency of 14 MHz through metallic shields of different design has been investigated. Despite for a normally incident wave the theory predicts the decay of the signal E/sub out//E/sub in/<0.01 (i.e. less -40 dBWt) for the shields used in the experiments, the decay of the measured signal was no less than -1.2 dB, i.e. anomalously large penetration of the signal through the metallic layer was detected. This effect can be caused by suppressing the magnetic component in the incident EM wave.