关键词: 电磁兼容性, 电磁屏蔽, 屏蔽效果

Abstract: This article is motivated by the great difference which has been found in the resultswhen comparing the shielding effectiveness of a metal plane with holes theoretically estimated by Keiser formula with that practically measured in experiment. Because the reflection was considered by B. E. Keiser, the transmission is considered here when electromagnetic waves coming to a metal with holes. This method is convenient for theoretical calculation and can be easily tested and verified by experiments. In accordance with the directivity function multiplication principle of antenna theory and the diffraction theory of electromagnetic wave, a theoretical calculating . formula has been obtained, which can be used to have an electromagnetic shielding effectiveness of a metal plane with holes, nearly having no difference when compared with the data practically measured. This formula is suitable for the following conditions: a definite ratio of hole diameter to distance between holes, hole diameter less than wavelength and distributional form of holes compact.

Key words: electromagnetic compatibility, electromagnetic shield, shielding effectiveness