Ouput isn't conjugated matched to the output of the power amlifiers.Instead Load-Pull technique is used to find the optimum load impedance which is seen by the amplifier itself.
In cadence Design Environment, you can simulate your circuit by changing real and imaginary part of your load impedance on the Smith Chart and at each point you note the Delivered Power.In order to change your load, you should use "Gamma" components in rf_lib ( as I remember ) that has variable real part and imaginary part.You can define these normalized variables by serially changing strings like ..
[0.5,0.1],[0.5,-0.1],[0.5,0.2],[0.5,-0.2]...etc..First define coarse points and then get them shrink in a narrow region.
In ADS, it's quite simple to do this..
There is a Load Pull Templates and by using this template, you may find optimum impedance.
All you should do is to replace the sample amplifier by yours.Of course don't forget to cahange Vdd and other biasing conditions and the operating frequency.
In advanced level, the optimum source impedance should be defined and harmonic impedances are also optimized..etc.