61.5% Efficiency and 3.6 kW/m² Power Handling Rectenna Circuit Demonstration for Radiative Millimeter Wave Wireless Power Transmission

A new GaN Nano-Schottky diode rectifier is introduced with capacitance per unit gate width of 381 fF/mm, and series resistance is 0.45 $\Omega \cdot $ mm leading to transition frequency ( $f_{\mathrm {T}}$ ) of 928 GHz. The associated forward current is 1.8 A/mm with breakdown voltage of 30 V. The new device was modeled and an on-wafer voltage doubler rectenna circuit was designed and fabricated on GaN/SiC wafers. A $W$ -band small and large signal characterization was performed to highlight the integrated rectenna performance. An RF-dc efficiency of 61.5% was measured at 95 GHz with associated input power density of 3.61 kW/m ² . The latter represents a 15.7% increase in efficiency over the state-of-the-art $W$ -band rectenna circuit. The input power handling has also increased by a factor of 1.5 and 9.5 from reported GaAs and CMOS-based rectenna circuits at 94 GHz. The result highlights key improvements in the rectenna metrics for wireless power beaming demonstrations of the future.