According to embodiments, small holes or openings may be cut on or through the ground plane(s) adjacent to a selected trace line, so that C and L will be changed accordingly. Then phase velocity will also be changed. As a result, the flying time from one location or point to a different location or point of the transmission line will also be changed. This concept applies to a single trace. Similarly, this concept may be applied to one trace of a differential pair of traces (e.g., so that the two parts of the differential signal transmitted at one point in time at a location on the pair arrive at the same time at another location of the pair).