Abstract: A low cost radio frequency interference filter assembly comprises a multiple layer structure including a middle trace layer disposed between an upper ground layer and lower ground layer. Non-conductive insulation layers are disposed between the middle trace layer and the upper and lower ground layers. The upper layer includes input contacts, signal contacts, and capacitors which are coupled to the signal contacts and an upper grounded substrate. The middle trace layer includes a grounded substrate and trace lines which are coupled to the signal contacts of the upper layer by signal vias. The lower layer includes a grounded substrate. Ground vias are formed through the insulation layers to couple the middle grounded substrate to the upper and lower grounded substrates. The filter assembly may be formed as an integral projection of a printed circuit board assembly.