Application of asymptotic waveform evaluation for analysis of skin effect in lossy interconnects

Asymptotic waveform evaluation (AWE) is a technique for time-domain analysis of electrical interconnects. AWE is a computationally efficient method that asymptotically approximates the response of a large system with a lower-order transfer function. Asymptotic waveform evaluation is used to analyze lossy interconnects including the skin effect. The internal impedance of the interconnect conductors varies as a function of the square root of the frequency. First, an overview of AWE is presented. The AWE formulation for modeling frequency dependent loss in the conductors is derived using two different series expansions of the system response at both s=0 and s≠0 in the Laplace domain. The expansions for s≠0 are determined using a transfer function formulated for inclusion of the frequency-dependent internal impedance. The network response is computed by extracting the dominant poles and residues using the Pade approximation. The proposed method is evaluated using time-domain examples of lossy multiconductor transmission lines