That document makes sense up until your actual question, which I can't make sense of. For driving a CMCD, or any SMPA in general, you usually DC bias the gate voltage slightly below the threshold (or pinch off in your case), so that nothing conducts if the RF input is turned off. The AC component of the gate drive must be high enough such that the FETs are driven well into their linear region of operation (not saturation, unless you're using bipolar devices).