Differential transmission line

摘要

A differential transmission line according to the present invention includes: a substrate 101 ; a ground conductor layer 105 formed on a rear side of the substrate 101 ; and a first signal conductor 102 a and a second signal conductor 102 b disposed in parallel to each other on a front side of the substrate 101 . The first signal conductor 102 a and the ground conductor layer 105 compose a first transmission line, whereas the second signal conductor 102 b and the ground conductor layer 105 compose a second transmission line. The first transmission line and the second transmission line compose a differential transmission line 102 c. The differential transmission line 102 c includes a curved region 104 a, with a straight region 104 b being connected to each end of the curved region 104 a. The line width of the first signal conductor 102 a in the curved region 104 a is denoted as Wb1; the line width of the second signal conductor 102 b in the curved region 104 a is denoted as Wb2; the gap width between the first signal conductor 102 a and the second signal conductor 102 b in the curved region 104 a is denoted as Gb; the line width of the first signal conductor 102 a in the straight region 104 b is denoted as Ws1; the line width of the second signal conductor 102 b in the straight region 104 b is denoted as Ws2; the gap width between the first signal conductor 102 a and the second signal conductor 102 b in the straight region 104 b is denoted as Gs; the shortest distance from the center of curvature 115 of the curved region to a line edge of the curved region of the first signal conductor 102 a that is closer to the center of curvature is denoted as Rb1; and the perpendicular distance from the center of curvature 115 of the curved region to an extension of a line edge of the straight region of the first signal conductor 102 a that is closer to the center of curvature is denoted as Rs1. Wb1 is prescribed to be narrower than Ws1; Wb2 is prescribed to be narrower than Ws2; Gb is prescribed to be narrower than Gs; and Rb1 is prescribed to be greater than Rs1.