Recent studies of Lim et al. have shown that channel engineering can effectively be used to globally improve the device noise performance. This happens because the doping profile can strongly impact the correlation between the drain and induced gate noise. In this brief, we will use the theory developed in the recent works of Roy et al. to provide a physical understanding and insight on the behavior of the gate-drain correlation coefficient, which will be very useful for understanding the mechanism by which the doping profile impacts the RF noise performance of a MOSFET.