Crosstalk-noise, which occurs mutual electrical interactions
between traces, is one of the most serious noises that decrease
signal integrity (SI) in PCBs (printed circuit boards) [6] [7] [8].
And the most troublesome point in the crosstalk is that it
increases as the signal frequency increases, and nothing but to
widen the spaces between the traces or to insert ground (shield)
traces between them has been the only determinant way to
reduce the noise so far. In the current high-frequency era of
GHz domain, the spaces between the traces thus must be
widened at the sacrifice of the trace-density in PCBs.