Worst-Case Scenarios of Radiated-Susceptibility Effects in a Multiport System Subject to Intentional Electromagnetic Interference

This paper presents a method to assess intentional electromagnetic interference (IEMI) in a linear multiport system, due to coupling with a high-power electromagnetic (HPEM) field. First, an approach based on the Lorentz reciprocity theorem is proposed to model field coupling for the arbitrary direction of incidence and polarization, which minimizes the number of required full-wave numerical simulations. Afterward, three constrained-optimization problems are identified to describe the worst-case scenarios related to different radiated-susceptibility effects at the system's ports. Namely, under the assumption of limited bandwidth and finite energy density, the spectrum and the waveform of the HPEM field are found so to maximize the dissipated energy, the peak, and the rectified impulse of the induced voltage waveform. It is shown analytically that in the worst-case energy scenario, the HPEM field shall be a properly tuned narrowband field, whereas in the worst-case voltage peak scenario a wideband field properly matched to the frequency response of the system is needed. In addition, it is shown that the rectified impulse of the induced voltage can be made arbitrarily large by reducing the impinging field bandwidth. A typical printed-circuit board interconnect for low-voltage differential signaling is used to exemplify and validate the proposed approach. Furthermore, uncertainty-quantification techniques are exploited to cope with the lack of knowledge about the incidence and polarization parameters of the HPEM field, as well as to account for uncertain geometrical parameters of the victim system.