Recent advances in the design and development of radio frequency-based energy harvester for powering wireless sensors: a review

Wireless sensor networks (WSNs) are spatially distributed sensor systems used to collect precise data from a large area of interest. WSN is usually deployed in the off-grid, and its widespread deployment is limited due to its requirement for the continuous and large amount of power. Energy harvesting has been recognized as a promising solution which has gained a lot of attention in recent years pertaining to enabling a self-sustainable operation of WSN. Radio Frequency (RF) is identified as an energy source that can be further used to harvest required energy for the WSN sensors. This paper outlines the motivation of RF energy harvesting for powering the WSN components. It is found that the rectenna circuit in RF harvester deals with very low amplitude of signals, and it requires further improvement in its feature and capabilities with reducing form factors. In this article, recent design and development consideration involved in rectenna circuit and corresponding performance trade-offs are being discussed. It also discusses the recent techniques involved in improving the overall power conversion efficiency of rectenna. The authors address the key challenging issues yet need to concentrate on further enhancements. This review will aid as a guide in the future, to develop an energy-efficient and high-performance RF harvester circuit, which needs to be taken to the next advance level.