A new multilayered common-mode filter on Ni-Zn ferrite substrate

A new multilayered common-mode filter was fabricated. It consisted of an inner coupled meander conductor line between top and bottom Ni-Zn ferrite substrates, polyimide dielectric interlayers, and outer surface ground planes. Since the Ni-Zn ferrite substrate had both magnetic and dielectric properties, the filter functioned as a coupled distributed constant line. The fabricated filter exhibited common-mode signal decay of 33 dB at around 3 GHz.