A Critical View on Various Test Methods for the Characterization of the Shielding Effectiveness of EMI Conductive Gaskets up to 40 GHz

This article highlights the specific application of two standardized test methods for the characterization of the shielding effectiveness of conductive gaskets, in the extended frequency range from 30 MHz up to 40 GHz. Each method is discussed with respect to its specific characteristics including advantages and disadvantages. Furthermore, two nonstandardized setups are also analyzed. Two different types of gaskets under recommended compression rates have been used to show the difference between the various test methodologies in relationship with their measuring setup, theory, and observations. Regarding the standard MIL DTL 83528G, the effects of both the antenna radiation patterns and the impinging angle of the fields are analyzed. Following the specific shielding effectiveness measuring results, recommendations are given for the choice of the test method corresponding the best to the real implementation in practice. It is also stated that the nonstandardized methods can easily be used for small samples of gaskets during development and/or for production control.