Control of aliasing in the harmonic balance simulation of nonlinear microwave circuits

A dual-frequency-set analysis scheme is proposed which reduces aliasing in the harmonic balance simulation of nonlinear microwave circuits without requiring excessive simulation time. The authors investigate the origin of aliasing and present a condition for determining the smallest acceptable transform frequency set which will reduce aliasing. This derivation is for periodic signals, however, the results can be extended to multiple incommensurate input tones if the transform is accomplished by a multidimensional FFT (fast Fourier transform). Results of some dual set analysis (e.g., for a MESFET amplifier) are presented.<>