A Simple Method to Identify Parametric Oscillations in Power Amplifiers Using Harmonic Balance Solvers

A qualitative method to verify the presence of parametric oscillations at ${f_{0}}/{2}$ in power amplifiers (PAs) is presented and validated. It relies on simultaneous application fundamental subharmonic tones trigger possible can be implemented any commercial harmonic balance solver without requiring external software that may expensive or however not available designer. Wide applicability guaranteed by fact this does require access internal node circuit. In fact, amplifier handled as a black-box where only input output ports are accessible. The stability check first demonstrated simplified case study then validated real K-band integrated PA, it correctly reproduces with simulations observed measurements. On redesigned amplifier, proposed test predicted absence oscillations, which has been confirmed experimental characterization.