the inductor should be RF high impedance so make it give u 10 or 20 times the impedance if u take a 50 ohm , then ur inductor ωL must be at least 500 , and also check the SFR of the inductor it should be at least be 3 times ur operation frequency
the capacitor must be RF short circuit so 1/ωc must be very low
note "u can replace the inductor by λ/4 microstrip line , with as high as possible Z0 , i mean as high as possible as narrow as u can get "
about the how to implement the bias network in ADS , first u should use nonlinear model not S parameter file , and study the DC behavior of ur FET and implement ur bias network , and run S parameter simulation with the nonlinear model , and the bias network
khouly