A geometry-physics based compact model for MOSFET-like CNTFET (Carbon Nanotube Field Effect Transistor) is presented. This model is developed in terms of basic geometry parameters like chiral index, doping concentration, number of tubes, pitch etc. This work presents a simpler way to model CNTFET using its energy profile. The non-idealities such as the quantum tunneling, the acoustical/optical phonon scattering in the channel region and the screening effect by parallel CNTs are modeled. The I-V characteristics are obtained over the entire region of operation for large signal (digital) applications. The CNTFET parameters have been optimized for an operating frequency of 500MHz for a channel length of 32nm. Particle Swarm Optimization technique is used to optimize the doping concentration, Nd and the chiral indices (n, m) with an objective to achieve high mobility and low capacitance. The optimal values are obtained for desired pitch and number of tubes. MATLAB and COMSOL are used to model the device and optimize the parameters. © 2016 Elsevier Ltd.