“…Polymers doped with conductive fillers, such as graphene [ 11 ], silver [ 12 ] or other metals [ 13 ], are able to increase the dielectric constant drastically, but at the expense of low compatibility with printed circuit boards (owing to large leakage current) and high signal attenuation (due to severe Ohmic loss). On the other hand, ferromagnetic dopants, e.g., Fe 3 O 4 [ 14 ], and ferroelectric dopants such as PZT [ 15 ], TiO 2 [ 16 , 17 , 18 ], SrTiO 3 [ 19 ], BaTiO 3 [ 3 , 4 , 5 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 ] or other oxides [ 17 , 18 ], are also good candidates. BaTiO 3 –polymer composites have attracted great attention among various combinations due to their high- k properties with high mechanical tunability and thermal stability.…”