Modeling of picosecond pulse propagation in microstrip interconnections of integrated circuits

Theoretical time-domain analyses of the dispersion and loss of square-wave and exponential pulses on microstrip transmission line interconnections on silicon integrated-circuit substrates, performed using the quasi-TEM approximation, are discussed. Geometric dispersion and conductor line width, as well as losses from conductor resistance, conductor skin effect, and substrate conductance, are considered over the frequency range from 100 MHz to 100 GHz. Results show the enormous significance of the substrate losses and demonstrate the need for substrate resistivities >10 Ω-cm for high-performance circuits. The results also show the effects of geometric dispersion for frequencies above 10 GHz, the unimportance of conductor skin-effect losses for frequencies up to 100 GHz, and the transition from a high-frequency regime where losses do not affect phase velocity to a low-frequency regime where the ratio of he conductor and substrate loss coefficients determines phase velocity