Accumulation of spatial charge on the surface of protecting coatings used against the penetration of high frequency electromagnetic fields

The article deals with the transmission of electromagnetic radiation through a selected building element. Measurements were made to determine the shielding effectiveness of the electromagnetic field. In order to increase the shielding effectiveness, shielding coatings were applied to the selected building element, some of which were concentrated with a laboratory-generated powder to improve the shielding effectiveness of the electromagnetic field. It has been found that a spatial charge occurs when an electromagnetic field impinging on the surface of shielding coatings. The size and polarity of the surface charge depends on the type of shielding coating, the frequency and duration of the electromagnetic field. Measurements were performed for the frequency range from 0.9 to 7 GHz.