Design and Fabrication of Milliwatt and Microwatt Microwave Rectifiers Based on Low Turn-On GaN Schottky Barrier Diodes

Low turn-on GaN Schottky barrier diodes (SBDs) and dedicated rectifiers for microwatt and milliwatt microwave rectification are designed and fabricated for the first time. GaN SBDs with a low turn-on voltage ( $V_{\mathrm {on}}$ ) of 0.32 V, a cutoff frequency ( $f_{T}$ ) of 139.47 GHz, a breakdown voltage ( $V_{\text {b}}$ ) of 30 V, and $f_{T} \times V_{\text {b}}$ / $V_{\mathrm {on}}$ figure of merit (FOM) up to 13.08 THz are achieved by carefully controlling the Ti/N ratios of Schottky anode. Milliwatt and microwatt rectifiers are designed utilizing customized low turn-on GaN SBDs. The measured maximum efficiency of 84.16% and 64.36% as well as ultrawide power dynamic range of 27 dB (-7 to 20 dBm) for milliwatt rectifier and 22 dB (-12 to 10 dBm) for microwatt rectifier are obtained. The result underscores the significant potential of GaN SBDs in applications not only limited to high-power scenarios but also extended to the milliwatt and microwatt regimes of microwave energy harvesting.