Direct Sensitivity Analysis of Nonlinear Distortion in RF Circuits Using Multidimensional Moments

Sensitivity analysis is a critically important aspect in the simulation of integrated circuits. It allows the designer to perform vital tasks such as circuit optimization and design space exploration. Recently, an efficient moments-based approach was presented for computing key distortion figures of merit in radio frequency circuits from the harmonic balance equations, without the need to perform a harmonic balance simulation. In this paper, we show how the moments method can also be used to perform an efficient and accurate sensitivity analysis through the computation of the expansions of the moment vectors with respect to a circuit parameter, i.e., the multidimensional moments. We show that the sensitivities of key distortion figures of merit, including the 1 dB compression point and different intercept points, at all outputs in the circuit can be obtained with minimal additional computation cost to that of the original algorithm, thereby providing insight into the circuit performance.