Coupling of Wideband Radiated IEMI to Cables above Ground

In this paper, transmission-line (TL) theory is applied to formulate a worst-case analysis for the assessment of wideband intentional electromagnetic interference radiated onto a cable harness (with terminal units) above ground. Given the bandwidth and the energy density of the high-power electromagnetic pulse impinging on the cable, the pulse spectrum maximizing the peak value of the common-mode voltage waveform induced at a cable end is obtained. Unlike in a full-wave solution to the problem, the proposed TL model allows for, first, deriving closed-form expressions in the special case of a cable terminated in a matched load at the opposite end; second, computationally efficient evaluation of the spectrum for any other loading conditions. The obtained results clearly unveil the impact of the system parameters (cable length, height, terminal loads, and pulse bandwidth) on the statistics of the worst-case voltage peak for the random direction of incidence and polarization.