how to simulate VSWR for Power Amplifier?

As specification, the PA should be stable even if the output VSWR=3:1

In ADS, I use the formula vswr(S22) to calculate it, the value is extrem high. I think this formula is only valid for small signal, not for PA.

Can any one tell me how to verify this specification in ADS?

Thanks!

No, the spec probably means the PA should be stable into a load of VSWR=3:1.
You may use a tuner element (i.e. a load pull tuner) to generate an all phase load of VSWR=3:1 or lower.

In power amplifier simulation you use large signal s-parameter simulation which is same as harmonic balance simulation to calculate port VSWR.

Akrcal
:D