Sensitivity of frequency-swept shielding effectiveness measurements to reflecting surfaces and EMI noise in the test area

This paper reports and compares empirical outcomes of frequency-swept Shielding Effectiveness (ES) measurements for several types of metallic enclosures, performed under two extreme conditions. In one case, the test is done in an area with numerous metallic surfaces and objects, while in the other case reflecting surfaces or objects are practically nonexistent. It is demonstrated that the frequency-swept data obtained from the two cases are well correlated, and that the existence of reflecting surfaces in the test area does not appear to be a significant source of error. These outcomes suggests that the frequency-swept method offers a quick and inexpensive method of measuring the effective SE of enclosures even in the presence of reflecting surfaces, large metal objects and EM noise from other equipment.