An Equivalent Method for Measuring Shielding Effectiveness of a Microminiature Electromagnetic Shield Using Its Large-Scale Model

Abstract

It's quite difficult to measure the shielding effectiveness of a microminiature shield due to its extremely small space. An equivalent testing method based on a large-scale model is proposed and outlined in this paper. The constraint relationship of the parameters between the original model and its large-scale model is deduced, and the conversion relation of the shielding effectiveness between the two models is also established. In this method, the large-scale model is obtained by enlarging the original microminiature model in proportion. Then, the shielding effectiveness of the large-scale model is measured by present available methods as well as instruments. The shielding effectiveness of the original model is obtained according to the derived relationship. Finally, this method is applied to a typical microminiature cube. Results show that the shielding effectiveness of the original model at frequency f is equal to that of its large-scale model at frequency f/n. It reveals that the equivalent method is correct and effective, providing an alternative and convenient way for the shielding effectiveness measurement of a shield with extremely small dimension.