A design procedure is tested in this paper where a Schottky diode connected in series on a microstrip line can be successfully modelled on a harmonic balance simulator, by a simple equivalent circuit. This model is shown to correctly describe the non-linear behaviour of the circuit for a wide range of operating points. A RF/DC power conversion circuit is designed by using this procedure and a very good agreement is found between the measured results and the simulations based on the derived model. It is expected that this procedure could successfully be used to design high efficiency rectennas for converting the microwave energy delivered by Space Solar Plants.