ABSTRACT
Delay lines, which consist of equal-length parallel sections closely packed together, are widely employed in high-speed printed circuit boards for delay time compensation and timing skew minimization between positive and negative lines in one differential pair. In order to reduce the circuit size of the routing area in a miniaturized design, the spacing between two adjacent parallel sections of the delay line should be smaller, but then faces an increase in electromagnetic coupling and crosstalk from adjacent sections when the high-speed signal passes through the delay line. From the results of past research concerning conventional serpentine and spiral delay lines, the crosstalk may affect system-level timing and possibly cause error switching of logic gates. Although there are many strategies for crosstalk reduction, crosstalk always exists and may result in Time-Domain Transmission (TDT) waveform degradation. In this paper, a novel geometry of a helix delay line with Rectangular-Patches (RPs) was proposed to significantly reduce crosstalk, and to improve the transient waveform and eye-diagram for maintaining Signal Integrity (SI).
