Asymmetric coupled lines for common-mode noise suppression in bent differential lines

In this Letter, novel asymmetric coupled lines are proposed to suppress common-mode (CM) noise in bent differential lines. Based on the concept of the relative permittivity of a single microstrip line, the width of the outer line is made smaller than that of the inner line in bent differential lines to reduce the time skew and the other design parameters are adjusted to account for the differential impedance. To verify the improvement afforded by the proposed method, the simulated and measured results of the proposed structure were compared with two different designs; the conventional bent differential lines and the compensated differential lines using a serpentine inner line. The results of the proposed method show better signal integrity than the other methods.