A Reconfigurable DC-Combined Rectenna Array for Ultrawide Dynamic Range Wireless Power Transfer Applications

This paper presents a novel reconfigurable DC-combined rectenna array for maintaining high RF-to-DC conversion efficiency in dynamic wireless power transfer (WPT) systems with movable transmitting source antennas. Conventional fixed combining topologies have inherent limitations, particularly in mitigating efficiency deterioration caused by variations in the received power distributions on the array aperture. To overcome this challenge, this work proposes an innovative control strategy integrating low-power double-pole double-throw (DPDT) switches to dynamically reconfigure the DC combining topology. This method exhibits ultra-wide dynamic range with negligible power consumption overhead compared with conventional active maximum power point tracking (MPPT) techniques. Experimental validation was conducted using a 4×4 Huygens dipole rectenna array. The designed reconfigurable rectenna array achieved a peak RF-to-DC efficiency of 74.4% and maintained efficiency between 60.0% and 74.8% when the transmitting source antenna moves within ±60° at 915 MHz, across a broad load voltage range (1.5 to 5.5 V) and a transmitted power range of 26 to 33 dBm. The results emphasize the importance of dynamic topology optimization, sub-array grouping, and minimal insertion loss in maximizing rectenna array efficiency for varying practical scenarios.