Bibliography 575
easily be controlled during the fabrication process, which is essential for single
mode propagation. Using “sliding contact” excitation the effective capacitance
was found to be zero to first order [50], which is most desirable for short electric
transients, cf. Eq. (12.12). But even with coplanar strip lines, sub-ps electrical
pulses (or slopes) cannot be propagated over more than several mm [51]. As
mentioned at the beginning of this chapter, they can be sent through considerable
distances in air or a dielectric bulk medium if suitable antenna–receiver structures
are used. There are speculations about utilizing soliton mechanisms to transmit
sub-ps electrical pulses over long distances in strip lines [52]. In analogy to
solitons