Patent ID: 7329818

Claim:
A transmission circuit board, comprising: a plurality of signal circuit layers disposed in an insulating plate; a plurality of ground layers disposed in the insulating plate for covering the signal circuit layers through an insulating layer; and a plurality of terminal portions penetrating through at least one of the signal circuit layers and the ground layers in a plate thickness direction and disposed at positions forming a plurality of rows and columns on a board surface; wherein said terminal portions include ground terminal portions situated in both end columns and signal terminal portions and are disposed on the board surface at crossing points of a grid pattern; each of said signal circuit layers includes signal connecting portions extending from circumferential surfaces of the signal terminal portions and wiring portions extending from the signal connecting portions in a column direction at positions of the rows and columns not overlapped with those in an adjacent signal circuit layer; said ground layers are formed in a plate shape extending in parallel to the board surface with a distance from the circumferential surfaces of the signal terminal portions, and are electrically connected to the ground terminal portions; said ground terminal portions are disposed at every other two rows in the both end columns; each of said signal circuit layers includes at least a pair of adjacent signal connecting portions electrically connected to a pair of the wiring portions arranged in parallel in a row direction or the column direction different from those on an adjacent signal circuit layer; and each of said ground layers is electrically connected to at least one of the ground terminal portions in the both end columns.