Sensitive Microwave Rectifier for High-Power Wireless Transfer Based on Ultra-Low Turn-On Voltage Quasi-Vertical GaN SBD

This paper presents the theoretical analysis and experimental validation of a harmonic-terminated high-efficiency and high-power microwave rectifier. The rectifier is designed utilizing a single-circuit gallium nitride (GaN) quasi-vertical Schottky barrier diode (SBD). Capitalizing on the strengths of wide bandgap, high mobility and high saturation velocity of the GaN, the SBD achieved a high breakdown voltage of 180 V and an ultra-low turn-on voltage of 0.23 V (at 1 A/cm$^{2}$). These characteristics enhance rectification performance across both high and low input power regions, making it suitable for wireless power transfer (WPT) applications. The optimized high-power microwave rectifier incorporates this advanced diode, featuring a wide input power range and high efficiency. The proposed rectifier structure includes a single-shunt self-developed SBD and topology with a harmonics compression network. It accomplishes a maximum RF-to-DC power conversion efficiency of 70.4% with an input power of 42 dBm (15.8 W) at 0.9 GHz. The highest efficient power handling ability is up to 20 W with an 18 dB (25–43 dBm) dynamic range achieving an efficiency exceeding 50%, demonstrating the high potential of high-power GaN SBDs for wireless high-power transfer for future microwave WPT applications.