Filter arrangement

A filter arrangement for eliminating radio frequency energy from signal energy in a signal line comprising:

• a multi-layer printed circuit board with at least two adjacent insulating layers having inner and outer surfaces, said inner surfaces of said insulating layers facing each other, and three conductor-containing layers on said surfaces of said insulating layers, a second conductor-containing layer extending on the outer surface of a first one of said insulating layers;
• a first conductor-containing layer of said multi-layer printed circuit board extending between said inner surfaces of said insulating layers, said first conductor-containing layer forming an input section and an output section and a filter region arranged therebetween with two spaced ends, said input section having a surface facing said second conductor layer and an opposite surface remote from said second conductor-containing layer;
• a third one of said conductor-containing layers extending on the outer surface of the second one of said insulating layers and remote from said second conductor-containing layer;
• said third conductor-containing layer comprising a connecting section of said signal line;
• means being provided for connecting said ends of said interrupted signal line with said connecting section, said means contacting said first conductor-containing layer only at the surface thereof remote from said second conductor layer;
• said second conductor-containing layer being grounded, whereby radio frequency energy in said input section of said signal line is displaced, due to an asymmetrical skin effect, towards said surface of said input section facing said grounded second conductor-containing layer, and whereby the connecting means contacting said remote surface transmit, at least, reduced radio frequency energy to said connecting section and said output section of said signal line.