Common-mode noise reduction on broadside-coupled delay line

Conventional edge-coupled differential delay lines are becoming popular choice on high-speed connection, which depend on their balanced property and superior immunity to noise interference. Although edge-coupled differential delay lines with differential signaling have many advantages, such as high noise immunity and low noise radiation, yet common-mode noise are becoming higher and higher resulting data rate approaches GHz level. Hence, broadside-coupled differential delay lines are proposed for common-mode noise reduction in this research. Simulation results show that time-domain common-mode noise on broadside-coupled serpentine and spiral delay lines can reduce 79 % and 84.57 % compared with edge-coupled serpentine and spiral delay lines. Similarly, frequency-domain differential to common-mode conversions have significant reduction at the frequency band of interest.