Figures of merit to characterize the importance of skin and proximity effects

This paper presents a transfer function based figures of merit that characterizes the importance of skin and proximity effects in the GHZ range. Most of the previous work derived figures of merit that depend on either the change in the resistance alone or the change in the summation of both the resistance and inductive impedance. However, careful analysis in this paper shows that deriving the figures of merit based on the interconnect transfer function is more relevant from the signal waveform point of view. These, transfer function based figures of merit set tighter upper bounds on the interconnect dimensions at which skin effect can be negligible. Error formulae that quantify the error in using the DC model of an interconnect, when the figures of merit are not met, are also derived. The simulation results agreed very well with both the figures of merit and the error formulae.