Test for Transfer Impedance (Shielding Effectiveness) of a Shielded Cable
Original Publication Date: 1982-Jul-01
Included in the Prior Art Database: 2005-Feb-09
A shielded cable is positioned parallel to a ground plane to establish characteristic impedance of a few hundred ohms for the shield and ground plane system. The shield is resistively loaded to have the same impedance. The cable is then tested by producing a known current at a known frequency on the shield and measuring the voltage in the signal conductor. The test gives relatively uniform value over a wide frequency spectrum because the matched shield impedance helps to reduce reflections.