Analysis and Modeling of a MOS Transistor with Long Gate Finger for Millimeter Wave Band Applications

Performance of a MOS transistor is drastically degraded in millimeter wave bend, in the case of long finger lengths. Th e reason is Longitudinal Distributed Effect (LDE) along the gate finger. LDE has been modeled in new commercially used (e.g. BSIM4) or under develop (e.g. BSIM6) RF-CMOS transistor models. An approximated approach has been used in these models that causes to considerable errors in the case of long finger lengths. In this paper we propose a new small signal model that accurately captures LDE in the case of long finger gates. Th e proposed model has been validated using the foundry design kit for TSMC 90nm RF CMOS technology