For the macromodel in descriptor systems, the existing methods require system decomposition, which greatly increase the compcatational time. A fast and efficient perturbation method is proposed for the passivity enforcement of S-parameter descriptor systems. The method generalizes quadratic programming with equality constraint introduced for regular systems which makes full use of matrix sparsity. It is implemented by perturbing some parameters of the DS to construct the objective function and constraint function of the quadratic programming problem. By using Lagrange multipliers, the complex ...
