Patent ID: 7495523
Filing Date: 2009-02-24
Classification: H01P,H05K

Abstract:
1. A differential transmission line comprising: a substrate; a ground conductor layer disposed on a rear side of the substrate; and a first signal conductor and a second signal conductor disposed on a front side of the substrate, the first signal conductor and the ground conductor layer composing a first transmission line, and the second signal conductor and the ground conductor layer composing a second transmission line, wherein, the differential transmission line includes two straight regions in which the first and second transmission lines extend linearly and a curved region interconnecting the two straight regions; the first signal conductor is disposed in a position relatively close to a center of curvature of the curved region, and the second signal conductor is disposed in a position relatively far from the center of curvature; a line width Wb1 of the first signal conductor in at least a portion of the curved region is smaller than a line width Ws1 of the first signal conductor in the straight regions; a line width Wb2 of the second signal conductor in at least a portion of the curved region is smaller than a line width Ws2 of the second signal conductor in the straight regions; a gap width Gb between the first signal conductor and the second signal conductor in at least a portion of the curved region is equal to or less than a gap width Gs between the first signal conductor and the second signal conductor in the straight regions; and a minimum value Rb1 of radius of curvature of a line edge of the curved region of the first signal conductor that is closer to the center of curvature is greater than a perpendicular distance Rs1 from the center of curvature to an extension of a line edge of each straight region of the first signal conductor that is closer to the center of curvature.