CMOS technology is one of the most frequently used technologies in the semiconductor industry as it can be successfully integrated with ICs.Every two years the number of MOS transistors doubles because the size of the MOSFET is reduced.Reducing the size of the MOSFET reduces the size of the channel length which causes short channel effects and it increases the leakage current.To reduce the short channel effects new designs and technologies are implemented.Double gate MOSFET design has shown improvement in performance as amplifiers over a single MOSFET.Silicon-based MOSFET design can be used in a harsh environment.It has been used in various applications such as in detecting biomolecules.The increase in number of gates increases the current drive capability of transistors.GAA MOSFET is an example of a quadruple gate around the four sides of channel that increases gate control over the channel region.It also increases effective channel width that improves drain current and reduces leakage current keeping short channel effects under limit.Junctionless MOSFET operates faster and uses less power with increase in ON-state current leading to a good value of /ON//OFF ratio.In this paper,several gate and channel engineered MOSFET structures are analyzed and compared for sub 45 nm technology node.A comparison among different MOSFET structures has been made for subthreshold performance parameters in terms of /OFF,subthreshold slope and DIBL values.The analog/RF performance is analyzed for transconductance,effective transistor capacitances,stability factor and critical frequency.The paper also covers different applications of advance MOSFET structures in analog/digital or loT/biomedical applications.