Accuracy Study of the Differential Surface Admittance Operator for Lossy Metal Characterization

The analytic, complete solution of a boundary integral formulation consisting of the electric field integral equation (EFIE) and the differential surface admittance (DSA) operator is presented for lossy conductors. Through a Galerkin Method of Moments with two complete sets of orthogonal vector spherical harmonics as basis functions, the complete system of equations is solved, including a closed-expression for the DSA elements via a generalized Fourier series. A comparison with the Mie series solution shows the range and accuracy of the DSA-EFIE formulation in dealing with lossy materials, and paves the way for a future study into the operator's fundamental properties, leading to improved tools for interconnect modeling that alleviate the identified dense-mesh and low-frequency breakdown.