Abstract
The power gain characteristics of MOSFET under common-source (CS) and common-gate (CG) configurations are analytically studied and verified with simulations using RF MOSFET large- signal models. The substrate parasitic effects on the power gain characteristics are also investigated. While little impact is observed on the CS power gain characteristics due to substrate parasitics, the power gain characteristics of the CG configuration are greatly and adversely influenced. High- frequency power-gain characteristics can be improved for the CG configuration with reduced substrate effects and lowered gate resistance values. The power gain potential of CG configuration could be eventually realized by using high- resistivity or SOI substrate and gate stacks of lower resistance.