thanks Element_115 for your reply
Im beginner in designing RF circuits now i design a class-E PA in 0.18um at2.4GHz and i simulated it in ADS , from your reply i understand that i can find the optimum load impedance with load-pull or on the other hand with sweeping load impedance.
OK , But now i have a question : If S-param dont give me correct output impedance in PA then How i can caculate the output impedance correctly in ADS?
If I calculate the correct output impedance of circuit , Is it true that i tell the optim load impedance is complex conjugate of this?
Ofcourse i have same problem for calculate input impedance of my designed PA because of i want to match the input and output to standard 50Ω.