“…Edberg et al (1991) added a second branch to a classical series RL shunt to mitigate two resonances, and this circuit was later generalized to an arbitrary number of modes by Hollkamp (1994). A number of other topologies were proposed since then, such as the current blocking shunt (Agneni et al, 2006;Wu, 1998), the current flowing shunt (Behrens et al, 2003), the seriesparallel impedance structure (Fleming et al, 2003), and a Cauer-type network (Goldstein, 2011). Each of these circuits proved rather difficult to tune, and numerical optimization was often needed for circuits with known (Cigada et al, 2012;Fleming et al, 2002;Gardonio et al, 2019) or unknown (Berardengo et al, 2017;Dal Bo et al, 2022) topology.…”