Historical methods of testing EMI gaskets

This paper presents the various test methods developed and employed to grade the effectiveness of EMI gaskets in sealing the seams of EMI shielded boxes and enclosures. The test methods presented and evaluated are: 1) Shielding Effectiveness Testing a. MIL-STD-285 b. MIL-STD-285 as re-defined by the EMC design engineering community c. SAE, ARP-1173 prepared by the EMC design engineering community d. MIL-G-83528 (superseded by ML-DTL-83528) 2) Transfer Impedance Test Methods - designed by the EMP design engineering community. The conclusion compares the shielding effectiveness test method presently being used with the transfer impedance test method. It also recommends revisions to the shielding effectiveness test method contained in MIL-DTL-83528 that will provide more accurate shielding levels and provide corrosion compatibility information of a gasket as tested against the various structural materials and finishes used by industry.