An Electronically Steerable Millimeter-Wave Reflectarray For Wireless Power Delivery

Wirelessly delivering power at millimeter-wave frequencies overcomes fundamental physical limitations on the range of lower frequency power delivery systems subject to size and maximum RF power density constraints. We identify the design of a cost-effective, solid-state system for steering a high-directivity beam as a primary challenge in implementing consumer and industrial millimeter-wave wireless power delivery systems, and present the design and measurements of a large-scale 61:5GHz electronically reconfigurable reflectarray to address this challenge. A dual-channel, two-bit reflective phase shifter IC implemented in 65nm CMOS forms the core of this design. The antenna array printed circuit board is implemented with a single RF laminate and the phase shifter ICs comprise only 3.5% of the aperture area, minimizing overall system cost. The demonstration array has 874 reflective elements in an area approximately 8:5cm in diameter, scans to +/- 50 degrees from boresight, achieves an aperture efficiency of approximately 8.7%, and consumes only 1:1mW of DC power.