Improving shielding effectiveness measurements with a spherical dipole antenna

This paper describes the effect of reradiated waves from the enclosure under test on shielding effectiveness measurements in which an optically-linked spherical dipole antenna is placed inside the enclosure. The results show a remarkable dependency of the measured shielding effectiveness on the receiving antenna height due to a height pattern difference between the reference field and the leakage field from the enclosure. This dependency reduces the measurement repeatability. A max-hold method is proposed to eliminate this effect so as to produce repeatable measurements