Embedded filter based on the BaTiO3-epoxy composite film

An embedded compact low-pass filter with parallel coupling and defected ground structure (DGS) is proposed based on the BaTiO_3- epoxy composite film. The physical size of the filter is compact due to the slow-wave effect of the DGS. It was embedded into a multi-layered FR-4 packaging substrate through the PCB manufacturing process. The theoretical and experimental results are presented and matched well. The models of embedded filter for different fabrication stages and an equivalent circuit were employed to analyze characteristics of the embedded filter. Theresults indicate that the parasitic capacitance induced by the supporting substrate(prepreg)has a large affect on the properties of the filter.