High-Efficiency 5.8-GHz Rectification Enabled by Doping-Optimized Quasi-Vertical GaN SBDs

In this paper, a device-circuit co-design approach for a 5.8-GHz rectifier is presented, utilizing doping-optimized quasi-vertical gallium nitride (GaN) Schottky barrier diodes (SBDs). To overcome the inherent performance limitations of fixed-parameter commercial diodes, a reverse-design methodology is proposed. By mapping epitaxial doping concentrations to device electrical parameters and decomposing the nonlinear rectification losses, the impact of drift-layer doping on the conversion efficiency is systematically analyzed. The analysis reveals that an optimal doping concentration of 2×1017 cm-3 minimizes the dominant losses. Accordingly, a custom quasi-vertical GaN SBD is fabricated, exhibiting favorable electrical characteristics, including a low turn-on voltage of 0.30 V, a breakdown voltage of 30 V, and a high cutoff frequency of 142 GHz. Experimental results demonstrate that the fabricated 5.8-GHz rectifier achieves a peak conversion efficiency of 70.8% at 15 dBm and a wide dynamic range of 19 dB (6–25 dBm). This performance successfully validates the proposed device-level optimization strategy for C-band wireless power transfer applications.