Patent ID: 8164005

Claim:
A multilayer high-frequency circuit board, comprising: a signal line layer in which a signal line for a high-frequency signal transmission is formed, the signal line including a first longitudinally extending side and a second longitudinally extending side; ground layers which are laminated on both sides of the signal line layer and each of which is grounded; and an interlayer circuit which is provided in the signal line layer which includes a signal line connecting portion connected to the signal line and having a center and an outer periphery, and which includes a ground connecting portion connected to the ground layers, extending concentrically with the signal line connecting portion from the first longitudinally extending side of the signal line to the second longitudinally extending side of the signal line around the outer periphery of the signal line connecting portion and having an inner periphery and an outer periphery, the inner periphery of the ground connecting portion surrounding the outer periphery of the signal line connecting portion with a gap between the inner periphery of the ground connecting portion and the outer periphery of the signal line connecting portion, wherein the outer periphery of the signal line connecting portion and the inner periphery of the ground connecting portion have similar shapes that are non-circular, and the outer periphery of the ground connecting portion has a circular shape being concentric with the center of the signal line connecting portion.