MEASUREMENT AND MODEL FOR CORRELATING PHASE AND BASEBAND 1 F NOISE INAN FET/

Phase noise in solid state oscillators arises in part from residual ph ase noise in the active device that provides gain. The device's residu al phase noise is usually attributed to baseband noise on the bias tha t upconverts via a mixing process to generate phase noise around the c arrier signal. This conclusion is consistent with the observation that baseband and carrier noise sources both have 1/f spectral properties. However, similar spectral properties are not sufficient to prove that the baseband and carrier noise are fully correlated. Experimental res ults presented here for a heterojunction FET show less than 40% correl ation. To account for these observations a new 1/f noise model is pres ented. This model is used to accurately predict the phase noise when a bias feedback circuit is added to stabilize the baseband fluctuations .