This paper presents an equivalent circuit approach used for the modelling of a point to point Wireless Power Transmission system at 2.45 GHz in a single non linear circuit simulator environment The measurements and simulations steps used for parameter extraction of the transmitting antenna, receiving antenna and the transmission channel are presented. The model validation of the complete system is then compared to the measured one at various distances. It is shown that using this approach, no electromagnetic simulation tool is required for the simulation and optimization of the overall system. Furthermore, this method enables the physical origin of the energy losses to be studied. The results obtained using this simple example show a relatively good agreement with the experiment and can form the basis for further developments of more complex systems.