Radiated Immunity Test Involving Crosstalk and Enforcing Equivalence with Field-to-Wire Coupling

In this study, a novel test procedure aimed at assessing the radiated immunity of units and subsystems interconnected by wiring harnesses is proposed and experimentally validated. The procedure is based on crosstalk and allows inducing at the terminations of the wiring structure under test the same disturbance that would be induced by field-to-wire coupling, without requiring large and expensive test facilities. This is made possible by resorting to a generator circuit laid parallel and in proximity of the cable under test and fed at the terminations by two RF voltage sources, whose phase shift is suitably controlled. The proposed scheme of equivalence is very general, holding for any direction of incidence and polarization of the impinging electromagnetic field. Also, it involves feeding conditions of the two RF sources that do not depend on the specific terminations of the circuit under test. Accuracy of the proposed equivalence scheme is assessed by resorting to an automatically controlled test setup involving a simple wiring structure and terminal networks. Eventually, feasibility and practicality of the associated test procedure are discussed.