Ultralow-Power Microwave Rectifier with TiN Anode GaN Schottky Barrier Diode

In this paper, TiN anode GaN Schottky barrier diodes (SBDs) are proposed for ultralow-power microwave rectification, targeting low-power radio frequency energy harvesting (RFEH) and wireless power transfer (WPT) applications. By optimizing the nitrogen gas pressure ratio during TiN deposition via magnetron sputtering, the trade-off between Schottky barrier height (SBH) and breakdown voltage (Vb) is systematically investigated. The GaN SBD with a low turn-on voltage of 0.34 V, a breakdown voltage of 28 V, and a junction capacitance of 0.14 pF, enabling a high cutoff frequency (fT) of 139.66 GHz, is achieved. A microwatt microwave rectifier operating at 900 MHz is designed and fabricated utilizing the customized GaN SBD. The measured peak power conversion efficiency (PCE) is 25.61% at -17.5 dBm input power, validating the feasibility of GaN SBDs in ultralow-power rectification and establishing a foundational framework for enhancing the performance of low-power rectifiers in energy harvesting applications.