Rectenna Design with High Efficiency at Lower Input Power Density for Sensor Network Applications

A high gain antenna array with flexible polarization configuration for wireless power transmission is proposed in this paper. An air substrate is utilized to improve the radiating efficiency of the array, and the feeding network is placed on the other side of the ground plane to realize a compact integrated rectenna design. By simply moving the feed location with respect to the symmetrical line of each patch element, the dual-polarized configuration of the array can be realized. Two array prototypes had been designed, optimized and fabricated. With $2^{\star}2$ systems, the prototypes achieve high gain up to 13 and 10 dBi and total efficiency exceeding 95%. The array has been integrated with a rectifier to form a rectenna illustrating its applicability for wireless power transmission in powering the sensor nodes for IoT applications.