Adjoint Technique for Sensitivity Analysis of Coupling Factors According to Geometric Variations

A physical interpretable equivalent electrical network and its parameters are extracted from a 3-D finite-element model formulated by Darwin's approximation to the Maxwell equations. In this paper, we add a sensitivity analysis procedure to the extraction of inductive parasitics, relying upon the adjoint technique for the extracted partial inductances and coupling factors. The resulting algorithm is an efficient way to calculate the sensitivities with respect to a large number of parameters. In an example, we use the gradient information to guide the geometrical optimization of an electromagnetic compatibility filter.