Distance and Misalignment Adaption Analysis of Inductive and Radio Frequency Power Transmission

Low-cost and low-power wireless sensor nodes are key components of the Internet of Things (IoT), which will grow rapidly in the next decades. To power millions of these devices flexibly without batteries, wireless power transmission (WPT) is a promising technology. In this paper, we elaborate the distance and misalignment adaption of far-field radio frequency (RF) power transfer (radiative) and near-field inductive power transfer (non-radiative) in the applications of ultra low power wireless sensor nodes. Their delivered power via the distance change or misalignment occurrence is analyzed. Combining the theoretical analysis and practical measurement, the capability of two WPT technologies are described clearly. The suitability of the technologies for different IoT applications are recommended.