A mixed surface integral formulation for frequency-dependent inductance calculation of 3D interconnects

A surface integral formulation based on direct boundary integral equation (BIE) was recently proposed for inductance or impedance calculation of 3D electric structures. Though faster than other volume integral methods, this formulation still suffers from as many as 7N7N unknowns, where N   is the number of panels. A mixed surface integral formulation is proposed in this paper, which combines indirect BIE of double-layer potentials within conductor and the direct BIE within dielectric. With this mixed formulation, the number of unknowns is cut down from 7N7N to 4N4N, and correspondingly, the CPU time for solving the linear equation system is reduced remarkably. Two interconnect structures are simulated to validate the proposed method.