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.