Large Signal Y-Parameter or S-parameter

Hi

I need to find large signal Y-parameters of a 2-port network such as a common source amplifier, in  Cadence.

Has anyone done something successful in this regard, please help me with it. Once I tried LSSP but the results did not make sense and the oscillator I designed based on small signal parameters worksd, whereas the one designed based on the LSSP results did not even oscillate!

Thanks,

Hamid