A coplanar-coupled-line common-mode filter using CoZrNb soft magnetic thin film for GHz frequency band

This paper describes a new type of common-mode filter for advanced digital signal interface with a data transfer rate of Gbps, such as IEEE 1394b (0.8-3.2 Gbps) and HDMI (high definition multimedia interface, 0.25-1.65 Gbps). The developed device is useful for GHz frequency common-mode filter. However, the frequency point of the maximum common-mode insertion loss was very close to the 3 dB balanced-mode insertion loss points. For applying the filter to the real applications such as IEEE 1394b or HDMI, maximum insertion loss point must be shifted to lower frequency band.