The great technological development we have achieved requires more efficient, small-scale, and low-power components .In this memory, a new analytical model for a Triple Material Gate (TM) GaAs MESFET has been proposed in order to suppress the short channel effects and improve the electrical behavior of the device. Therefore, the aim of this work is to demonstrate the improved electrical performances exhibited by (TM) GaAs MESFET over dual material gate and conventional single material gate MESFET. This approach is based on development of I-V characteristics, transconductance and cut off frequency of TM GaAs MESFET. The model is further extended to evaluate the I-V characteristic, transconductance and cut-off frequency including the effect of third region length for microwave frequency applications. The obtained results demonstrate that TM GaAs MESFET presents an alternative solution to designer for high frequency applications.