Transfer Impedance Testing of EMI Gaskets

Abstract

The transfer impedance testing of Electromagnetic Interference (EMI) gaskets as described in SAE ARP-1705 revision C is documented. The specification includes two test fixtures. These fixtures are 1705A and 1705C. The 1705A test fixture tests over the frequency range of 10 kHz through 1 GHz with an accuracy of ± 2 dB. The 1705C test fixture tests with an accuracy of ± 2 dB over the frequency range of 10 kHz through 18 GHz. The 1705A fixture tests for (1) the conductivity of the gasket against any of the structural materials and finishes used by industry; (2) the conductivity of a test sample as a function of the force of the gasket against the joint surfaces; and (3) the effects moisture and salt fog have on the ability of the gasket to provide the required shielding. The 1705C fixture tests for the conductivity of the gasket against any of the structural materials and finishes used by industry and the effects the force of the gasket against the joint surfaces has on the conductivity.