Shielding Efficiency Measuring Methods and Systems

The most appropriate method and instrument need to be selected to obtain reliable measurement results for shielding effectiveness (SE). This chapter mainly contributes most commonly used standard measurement methods and systems for determining the electromagnetic interference SE (EMI SE). It also discusses the effect of various parameters on EM SE. Then, the chapter considers four test methods to measure EMI SE of a given shielding material. The methods used to retrieve the results often vary according to the particular shielding application: Open field or free space test; shielded box test; coaxial transmission line test; and shielded room test. The chapter shows the elementary test set up for experimental determination of SE. The method and test standards generally used in assessing the EM SE, with a finished enclosure constructed from the material, are IEEE STD-299 and ASTM E 1851.