The microwave wireless power transfer is a power transmission device that breaks through the limitation of the transmission line, and is helpful for handling equipment power supply problems in complex scenes. Thus, it has a wide array of applications. This paper focuses on the research and design of the core components of the receiving part of the microwave wireless power transfer, it optimizes the material physical parameters and geometrical parameters of the device to improve the energy conversion efficiency. First, we using the ADS simulation tool, the relationship between the electrical parameters of the schottky diode and the energy conversion efficiency is obtained by adjusting the SPICE parameters of the schottky diode. The optimal design principle is proposed, which lays a theoretical foundation for the optimization design of the subsequent high energy conversion efficiency rectifier device. Second, basing on the diode rectification principle and the theoretical basis obtained in the first part, a GeSn folded space charge on the insulating layer is proposed. Using the device simulation tool Silvaco to adjust the physical parameters of the device material and the geometrical parameters, the device structure of the GeSnOI folded space charge region Schottky diode is obtained. The results show that compared with the traditional structure Ge schottky diode, the folded space charge region schottky diode optimized in this paper has the advantage of significantly improving its energy conversion efficiency, and the energy conversion efficiency is improved by 8.1%.