Design of multi-channel AlGaN/GaN Schottky diode for improving rectification efficiency in microwave power transmission

Abstract

Schottky barrier diode (SBD) is the core of the rectification circuit in the microwave power transmission (MPT) system and suitable for high-power RF-DC conversion. However, the rectification efficiency of current commercial SBD cannot meet the requirements of the MPT system. Therefore, this paper proposes a microwave rectification circuit based on the multi-channel AlGaN/GaN SBD. The effect of diode parameters on the rectification efficiency has been investigated, such as the number of channels, the length of anode field plate (LAFP) and the thickness of insulation layer. Simulation results show that multiple AlGaN/GaN heterojunctions can significantly reduce the on-resistance of SBD and improve the rectification efficiency. The power capacity of SBD can be increased withthe optimised LAFP and the thickness of insulation layer, which enables efficient microwave rectification in high power applications. High RF-DC rectification efficiency of 85.1% is obtained at the input power of 33 dBm. The rectification efficiency exceeds 60% over a wide input power range (14–38 dBm). The results demonstrate the great potential of multi-channel AlGaN/GaN SBD for high-power MPT application.