Improvements of time-domain transmission waveform in serpentine delay line with guard traces

As the signal frequency goes higher, the crosstalk noise has become the major signal integrity concern for the design of various delay lines. Since the guard trace is increasingly adopted to alleviate the mutual coupling effect in modern highspeed digital system, this paper qualitatively investigates its effects on the time-domain transmission (TDT) waveform and eye diagram of the serpentine delay line. Based on HSPICE simulation, it is demonstrated that the utilization of the guard traces can reduce the original TDT crosstalk level by more than 50%, thereby greatly improving the eye opening and jitter. Finally, the time-domain measurement is also performed to validate the proposed analyses.