Optimizing RF Energy Harvesting for IoT Devices: Impedance Matching and Voltage Multiplier Solutions

The escalating demand for energy-efficient solutions has become increasingly pronounced in the contemporary landscape of interconnected Internet of Things (IoT) devices. One promising avenue for meeting the power requisites of IoT devices involves Radio Frequency (RF) energy harvesting, which harnesses ambient RF waves. Nevertheless, a significant challenge in optimizing power transfer efficiency from RF sources is primarily attributed to impedance discrepancies. This investigation delves into the ramifications of impedance matching on the performance of RF energy harvesting circuits tailored for IoT applications. It scrutinizes the potential of the Cockcroft-Walton voltage multiplier (CWVM) as a proficient energy multiplication technique, concentrating on optimizing power transfer efficiency. We introduce a matching network to adjust impedance parameters to facilitate this optimization. Furthermore, the study integrates a wideband energy harvesting circuit capable of capturing RF energy across diverse frequencies. Empirical measurements conducted under various impedance configurations underscore the intrinsic value of impedance-matching strategies in amplifying power extraction from RF sources. These findings substantiate the substantial impact of impedance mismatch on power transfer efficiency and underscore the critical importance of adept impedance-matching techniques in optimizing energy scavenging capabilities.