Non-Invasive Optimal Coupling upon Detection of a Local Change of Impedance in a Cable Network

In this paper, we apply a novel wavefront shaping technique within a cable network. By manipulating an array of crosstalk sources at different locations of the network, we demonstrate experimentally a strong enhancement of the intensity at a specific wire end where an impedance change occurs. The optimal wavefront for maximal focusing is determined non-invasively using the generalized Wigner-Smith operator. Our approach relies on two successive measurements of the scattering matrix at the injection ports, before and after the change. The optimal wavefront then closely corresponds to the first eigenstate of the generalized Wigner-Smith operator. Thus, a maximum focused intensity is reached at a remote distance without cooperation of the target, opening up new perspectives in the context of electromagnetic aggressions or attacks (cybersecurity).