Power-Combined Rectenna Array for X-Band Wireless Power Transfer

This work presents an RF power-combined rectenna array operating at 10 GHz and designed for low incident power densities ranging from 0.1-100 μW/cm^2. The array consists of unit-cell sequentially-fed four-element patch antenna subarrays designed to receive incident waves with circular polarization. The incident power is converted to dc using a single-ended Schottky diode rectifier. The rectifier is first characterized over input power and dc load individually and with a single sub-array. A 4-to-1 RF power-combining network is designed to further improve RF-to-dc conversion efficiency and output power at the lower-bound power density of 0.1 μW/cm^2. A three-layer PCB with off-the-shelf components enables straightforward scaling to larger apertures.