An alternative approach to radiated susceptibility testing of airborne equipment

In this work, an alternative test procedure for unit-level radiated susceptibility (RS) testing of airborne equipment is theoretically investigated. The proposed approach applies to units interconnected by multi-wire shielded bundles, and resorts to an auxiliary wiring structure-placed in close proximity of the interconnecting bundle-in order to reproduce via crosstalk (XT) the same electromagnetic disturbances induced into the terminal units by radiation. To this end, a suitable equivalence scheme between the two excitation techniques is developed with reference to a typical RS test setup (RTCA DO-160). The equivalence holds for vertically-polarized fields, and requires to feed the auxiliary circuit at midpoint by a frequency-independent voltage source. Theoretical results are validated by multiconductor transmission line theory, and by electromagnetic simulation.