In this paper we present a compact model of Double-Gate MOSFET architecture including ballistic and quasi-ballistic transport down to 20 nm channel length. In addition, this original model takes into account short channel effects (SCE/DIBL) by a simple analytical approach. The quasi-ballistic transport description is based on Lundstrom's backscattering coefficient given by the so-called flux method. We also include an original description of scattering of processes by introducing the “dynamical mean free path” formalism. Moreover, we implemented our model in a Verilog-A environment, and applied it to the simulation of circuit elements such as CMOS inverters and Ring Oscillators to analyze the impact of ballistic/quasi-ballistic transport on circuit performances. Finally, in order to validate our work, we confronted this model with numerical simulation of CMOS and Ring Oscillator in ballistic case.