H.B. simulation in ADS, Harmonics are nothing or desabled !!!

Dear all,
Hi.
I simulate a MMIC RF power amplifier (PA) in ads (advanced design system), s-param simulation is working well but harmonic balance not. Increasing the input signal power of the PA, the output signal power increases unconditionaly, even more then DC power dissipation. 3rd order harmonic of the output signal also is flat and in the level of Nothing(!) like the images below:
Attachment 71965
Attachment 71966
The specification table of the PA is as follows:

I am wondered about the problem.
Please feel free, any suggestion or idea will be welcome.
Thanks.

Hi,

without some schematic is hard to say where is your problem!

Best regards

S-params is for small signal, not for large signal, so you can't increase the input signal to exceed the IIP1 dBm.

Dear all.
Thanks.
S-param simulation phase is passed true, but the problem is that in Harmonic Balance, which i deside to find nonlinearities, only the first harmonic will appeared and no 2nd or 3rd harmonics will be available.
I think the problem may be with the model I used. Beacause, some other FETs in the library have 2nd and 3rd harmonics too but with very high nonlinearities and low gains!