Equivalent SPICE Circuits With Guaranteed Passivity From Nonpassive Models

In this paper, a new fast technique of passivity enforcement of a nonpassive rational model is introduced. The technique disturbs poles of the model to restore passivity in such way that the frequency response of a device being modeled is preserved. The passivity enforcement procedure is defined as an optimization routine with the gradients of the cost function evaluated using the theory of matrix perturbation. The rational model can be based either on passive (electromagnetic simulations, measurements) or nonpassive (surrogate models) data. In the second case, the proposed technique can lead to a parameterized SPICE networks. Some advanced examples are given to show the application of proposed approach in interconnect, packaging, and signal integrity analysis