Circuit board device

A circuit board device for transmitting signals at a frequency of 50 GHz to 300 GHz, comprising:

• an insulation portion having a top surface and a bottom surface;
• a first interlayer connective structure passing through the insulation portion to define a signal path, wherein the first interlayer connective structure comprises:
• a first pillar passing through the insulation portion and having two opposite first end surfaces, wherein the first pillar comprises:
• a pair of first end portions having respective first end surfaces;
• and
• a first central section connected between the first end portions, wherein a first wall thickness of each of the first end portions is greater than a second wall thickness of the first central section;
• a first reference layer located on the top surface of the insulation portion, wherein the first reference layer is separated from the first interlayer connective structure and surrounds the first interlayer connective structure;
• a second reference layer located on the bottom surface of the insulation portion, wherein the second reference layer is separated from the first interlayer connective structure and surrounds the first interlayer connective structure;
• and
• at least one second interlayer connective structure passing through the insulation portion, wherein two opposite second end surfaces of the second interlayer connective structure are respectively connected to the first reference layer and the second reference layer to define a ground path that surrounds the signal path,
• wherein an upper surface and a lower surface of the circuit board device comprise the respective first end surfaces.