Verification of Feed-Through Configurations by Means of Simple Test Apparatus on Component Level

Feed-through configurations within high speed data transmission systems can cause serious electromagnetic interference (EMI) problems. A simple test method to measure the transfer impedance and shielding or screening attenuation of feed-through configurations and EMI - gaskets in well defined environments has been developed and tested with good results. Using the scattering parameters measured with a network analyzer (NWA), the transfer impedance is calculated. It is the primary and test fixture independent screening effectiveness measure and allows an estimation of the screening efficiency also within systems with different system impedances. Various feed-through shielding approaches have been evaluated and compared by the use of this method.