“…Due to the difficulties in the analysis of the high-order subharmonic injection-locked regime, approximate oscillator models are used in [5]- [6], [12]- [14], whereas the simulations in [7], [15] rely on the Poincaré-map technique [16]- [18]. This map is applied to the sequence of steady-state solutions obtained through time-domain integration of the differential algebraic equation system when varying a particular analysis parameter, such as the input power or frequency.…”