Practical high speed gradient computation for harmonic balance simulators

The authors introduce a powerful computational concept called the future adjoint sensitivity technique (FAST). FAST is an expedient tool for gradient calculation in the harmonic balance environment. FAST combines the efficiency of the exact adjoint sensitivity technique with the simplicity of the conventional perturbation technique. The same concept carries over to a practically implementable Jacobian for fast harmonic balance simulation. FAST promises high-speed gradient evaluation essential for yield optimization of nonlinear monolithic microwave integrated circuits by general purpose of software. The features of FAST and its Jacobian extensions are illustrated by a mixer example and a frequency-doubler example.<>